Search Results (129)

The identification of supplementary cultivated land as a reserve resource is of great significance for ensuring implementation of the new mechanism of land occupation and compensation balance in China. Using Jiangsu Province as a case study, here, we use a “multi-period land use change patterns–multi-scenario land use simulation–cultivation suitability evaluation–identification of supplementary cultivated land” framework to explore identification of supplementary cultivated land. A single land use dynamic index and a land use transfer matrix were used to analyze land use pattern changes in Jiangsu Province and showed that the area of cultivated land in Jiangsu Province decreased significantly, mainly by being converted into land used for buildings, and waters and conservancy facilities. A Markov-FLUS model was used to simulate and predict land use quantity and spatial distribution under four scenarios: an inertial development scenario, a cultivated land protection scenario, an economic development priority scenario, and an ecological protection priority scenario. Sixteen factor indicators were selected from the four dimensions of natural land quality, social economy, management, and the ecological condition of the land, and the degree of suitability of cultivated land in Jiangsu was evaluated by multi-factor stepwise correction. The southern and central parts of Jiangsu had higher suitability, while the northern part had lower suitability. By superimposing these data on current land use data from 2023, the plots of land that were converted to or from cultivated land were identified. Combined with the suitability degree, the potential three major categories and eight types of sources for supplementary cultivated land, totaling 29,015.92 km², were identified, along with their distribution. A time sequence arrangement for these sources was initially set up. Corresponding management suggestions were proposed based on the adaptability of different supplementary cultivated land sources, with the aim of providing scientific references for the acquisition of supplementary cultivated land sources in the implementation of the national and local government’s farmland balance management. Full article

To achieve low-cost and flexible wheel angles measurement, we propose a novel strategy that integrates wheel segmentation network with 3D vision. In this framework, a semantic segmentation network is first employed to extract the wheel rim, followed by angle estimation through ICP-based point cloud registration. Since wheel rim extraction is closely tied to angle computation accuracy, we introduce APCS-SwinUnet, a segmentation network built on the SwinUnet architecture and enhanced with ASPP, CBAM, and a hybrid loss function. Compared with traditional image processing methods in wheel alignment, APCS-SwinUnet delivers more accurate and refined segmentation, especially at wheel boundaries. Moreover, it demonstrates strong adaptability across diverse tire types and lighting conditions. Based on the segmented mask, the wheel rim point cloud is extracted, and an iterative closest point algorithm is then employed to register the target point cloud with a reference one. Taking the zero-angle condition as the reference, the rotation and translation matrices are obtained through point cloud registration. These matrices are subsequently converted into toe and camber angles via matrix-to-angle transformation. Experimental results verify that the proposed solution enables accurate angle measurement in a cost-effective, simple, and flexible manner. Furthermore, repeated experiments further validate its robustness and stability. Full article

Recently, the kinetic improvement of the nitrogenation reaction of lithium hydride (LiH) to form lithium imide (Li₂NH) by adding a scaffold was reported. The scaffold prevents agglomeration of Li₂NH and maintains the activity of LiH, achieving a reduction in reaction temperature and an increase in reaction rate. In this work, a Li–Si alloy, Li₂₂Si₅, was used as a starting material to form nano-sized LiH dispersed in a Li alloy matrix. Lithium nitride (Li₃N) is generated by the reaction between Li₂₂Si₅ and N₂ to form Li₇Si₃, and then Li₃N is converted to LiH with ammonia (NH₃) generation during heat treatment under H₂ flow conditions. Since Li₃N is formed at the nano-scale on the surface of alloy particles, LiH generated from the above nano-Li₃N is also nano-scale. The differential scanning calorimetry results indicate that direct nitrogenation of LiH in the alloy matrix occurred from around 280 °C, which is much lower than that of the LiH powder itself. Such a highly active state might be achieved due to the nano-crystalline LiH confined by the Li alloy as a self-transformed scaffold. From the above experimental results, the nano-confined LiH in the alloy matrix was recognized as a potential NH₃ synthesis technique based on the LiH-Li₂NH type chemical looping process. Full article

We study basis-independent structures in the Type-I seesaw mechanism for light Majorana neutrinos, assuming the canonical scenario with three heavy right-handed (sterile) neutrinos. Let $m_{\nu }$ denote the $3\times 3$ mass matrix of light neutrinos, obtained at tree level from heavy Majorana singlets with a diagonal mass matrix $D_N=\mathrm{diag}(M_1,M_2,M_3)$ and a Dirac matrix $m_D$. We show that all right actions F on the seesaw matrix that leave $m_{\nu }$ unchanged form the group $G=D_N^{1/2}O(3,\mathbb{C})D_N^{-1/2}$. While oscillation data determine the PMNS matrix $U_{\mathrm{PMNS}}$ and the mass-squared splittings, they do not fix the F-class within G. We classify basis-invariant quantities into those that are class-blind (e.g., $det \eta$) and class-sensitive (e.g., $\mathrm{Tr}\eta$, $\mathrm{Tr}{\eta }^2$, an alignment measure, and CP-odd traces relevant to leptogenesis), where $\eta$ denotes the non-unitarity matrix of the light sector. We provide explicit formulas and both high-scale and GeV-scale benchmark examples that illustrate these invariant fingerprints and their scaling with $D_N$. This converts the degeneracy at fixed $m_{\nu }$ into measurable, basis-invariant fingerprints. Full article

This paper proposes a single-phase AC-AC solid-state transformer (SST) that eliminates bulky energy storage components. The proposed matrix-type structure comprises a line-frequency (LF) rectifier, a half-bridge (HB) LLC resonant converter, a buck–boost converter, and an LF inverter. The HB LLC resonant converter not only achieves high efficiency at unity voltage gain but also provides high-frequency (HF) isolation as a DC transformer (DCX). Meanwhile, the buck–boost converter ensures precise voltage regulation. The replacement of traditional DC-link electrolytic capacitors with small film capacitors effectively suppresses the second-harmonic power ripple, leading to a significant improvement in both power density and operational reliability. Experimental results from a 1 kW prototype demonstrate high-quality sinusoidal input and output, a wide range of zero-voltage switching (ZVS) operations, and stable output voltage control. Full article

Driven by 5G/6G and the Internet of Things (IoT), wireless sensor networks (WSNs) are confronted with core challenges such as limited energy constraints, unbalanced resource allocation, and security vulnerabilities. To address these, WSNs are integrated with cognitive radio networks (CRNs) to alleviate spectrum scarcity, and reconfigurable intelligent surfaces (RIS) are adopted to enhance performance, but traditional passive RIS suffers from “double fading” (signal path loss from transmitter to RIS and RIS to receiver), which undermines WSNs’ energy efficiency and the physical layer security (PLS) (e.g., secrecy rate, SR) of primary users (PUs) in CRNs. This study leverages symmetry to develop an active RIS framework for WSN-integrated CRNs, constructing a tripartite collaborative model where symmetric beamforming and resource allocation improve WSN connectivity, reduce energy consumption, and strengthen PLS. Specifically, three symmetry types—resource allocation symmetry, beamforming structure symmetry, and RIS reflection matrix symmetry—are formalized mathematically. These symmetries reduce the degrees of freedom in optimization (e.g., cutting precoding complexity by ~50%) and enhance the directionality of green interference, while ensuring balanced resource use for WSN nodes. The core objective is to minimize total transmit power while satisfying constraints of PU SR, secondary user (SU) quality-of-service (QoS), and PU interference temperature, achieved by converting non-convex SR constraints into solvable second-order cone (SOC) forms and using an alternating optimization algorithm to iteratively refine CBS/PBS precoding matrices and active RIS reflection matrices, with active RIS generating directional “green interference” to suppress eavesdroppers without artificial noise, avoiding redundant energy use. Simulations validate its adaptability to WSN scenarios: 50% lower transmit power than RIS-free schemes (with four CBS antennas), 37.5–40% power savings as active RIS elements increase to 60, and a 40% lower power growth slope in multi-user WSN scenarios, providing a symmetry-aided, low-power solution for secure and efficient WSN-integrated CRNs to advance intelligent WSNs. Full article

Traditional low-cost DC drives, such as Buck converter-fed DC drives, do not take into consideration the power quality requirements regarding the total harmonic distortion (THD) and the input power factor (PF). This paper proposes a high-performance one-quadrant DC drive based on the ultra-sparse matrix rectifier (USMR). The scheme is suitable for single-quadrant applications such as DC pumping systems. The proposed system leverages the advantages of the USMR, such as the accomplishment of the IEEE standards requirements related to harmonic limits and distortions of the AC currents and operation at (or near) unity PF. Two pulse width modulation (PWM) techniques were investigated: the hysteresis current controller with a tolerance band and the triangular carrier-based PWM modulator. The system was studied under different operating conditions. The obtained results demonstrate the high performance of the USMR system with both types of PWM techniques. A comparative study with the one-quadrant Buck converter-based DC drive was conducted. The USMR-based DC drive outperforms the conventional scheme in power quality issues. The quantitative assessment proves the validity and suitability of the USMR for developing high-performance DC drives for single-quadrant applications. Full article

Osteoarthritis (OA) lacks disease-modifying therapies, in part because key features of the joint microenvironment remain underappreciated. One such feature is localized acidosis, characterized by sustained reductions in extracellular pH within the cartilage, meniscus, and the osteochondral interface despite near-neutral bulk synovial fluid. We synthesize current evidence on the origins, sensing, and consequences of joint acidosis in OA. Metabolic drivers include hypoxia-biased glycolysis in avascular cartilage, cytokine-driven reprogramming in the synovium, and limits in proton/lactate extrusion (e.g., monocarboxylate transporters (MCTs)), with additional contributions from fixed-charge matrix chemistry and osteoclast-mediated acidification at the osteochondral junction. Acidic niches shift proteolysis toward cathepsins, suppress anabolic control, and trigger chondrocyte stress responses (calcium overload, autophagy, senescence, apoptosis). In the nociceptive axis, protons engage ASIC3 and sensitize TRPV1, linking acidity to pain. Joint cells detect pH through two complementary sensor classes: proton-sensing GPCRs (GPR4, GPR65/TDAG8, GPR68/OGR1, GPR132/G2A), which couple to G_s, G_q/11, and G_12/13 pathways converging on MAPK, NF-κB, CREB, and RhoA/ROCK; and proton-gated ion channels (ASIC1a/3, TRPV1), which convert acidity into electrical and Ca²⁺ signals. Therapeutic implications include inhibition of acid-enabled proteases (e.g., cathepsin K), pharmacologic modulation of pH-sensing receptors (with emerging interest in GPR68 and GPR4), ASIC/TRPV1-targeted analgesia, metabolic control of lactate generation, and pH-responsive intra-articular delivery systems. We outline research priorities for pH-aware clinical phenotyping and imaging, cell-type-resolved signaling maps, and targeted interventions in ‘acidotic OA’ endotypes. Framing acidosis as an actionable component of OA pathogenesis provides a coherent basis for mechanism-anchored, locality-specific disease modification. Full article

This article presents the results of experimental studies to determine the possibility of processing steelmaking slags into an artificial granulated filler for concrete by the method of forced carbonization and the stabilization of the obtained filler in the concrete matrix over time. The utilization of metallurgical waste and technogenic CO₂ is a global problem. In this work, the method of the granulation of finely ground converter (BOF) and electric steelmaking (EAF) slags was used to obtain artificial granules and their subsequent forced carbonization in the developed laboratory carbonization chamber. Within the framework of this study, the quantitative binding of CO₂ by granules based on BOF and EAF slags was established, which amounted to 5.2 and 7.8% by weight, respectively. It was determined that the mass loss during crushability testing, indirectly characterizing the actual compressive strength of the granule material, depending on the type of slag and grain size, ranges from 13.6 to 42.3%, which is quite sufficient for using this artificial filler in concrete production. Based on the developed batches of fillers, concretes were obtained that have a compressive strength of 30.7 to 37.8 MPa in 28 days of hardening, which generally corresponds to concrete class B25. The preliminary studies and the results obtained indicate the prospects of processing steel slags into artificial granulated fillers by forced carbonization and using this product in concrete production. Full article

This research evaluates the stabilization of a clay collected from the northern expansion zone of Cartagena de Indias, Colombia. Laboratory analyses, including particle size distribution, Atterberg limits, compaction, specific gravity, and XRF/XRD, classified the soil as a highly plastic clay (CH) with moderate dispersivity, as confirmed by pinhole and crumb tests. The soil was treated with 3–9% lime, with and without the addition of NaCl (0% and 2%), and tested for unconfined compressive strength (q_u), small-strain stiffness (G_o), and microstructural properties under curing periods of 14 and 28 days at two compaction densities. Results showed that lime significantly improved mechanical behavior, while the inclusion of NaCl further enhanced q_u (up to 185%) and G_o (up to 3-fold), particularly at higher lime contents and curing times. Regression models demonstrated that both q_u and G_o follow power-type relationships with the porosity-to-lime index, with consistent exponents (−4.75 and −5.23, respectively) and high coefficients of determination (R² > 0.79). Normalization of the data yielded master curves with R² values above 0.90, confirming the robustness of the porosity-to-lime framework as a predictive tool. The G_o/q_u ratio obtained (3737.4) falls within the range reported for cemented geomaterials, reinforcing its relevance for comparative analysis. SEM observations revealed the transition from a porous, weakly aggregated structure to a dense matrix filled with C–S–H and C–A–H gels, corroborating the macro–micro correlation. Overall, the combined use of lime and NaCl effectively converts dispersive clays into non-dispersive, mechanically improved geomaterials, providing a practical and sustainable approach for stabilizing problematic coastal soils in tropical environments. Full article

In this study, a production method for ceramic shell macrocapsules and a high-temperature-resistant, polymer agent-based self-healing system was developed. Two types of macrocapsules were created by filling hollow ceramic capsules with high-temperature-resistant diallyl phthalate (DAP) resin, known for its thermal stability, and a peroxide-based curing agent. These capsules were incorporated into epoxy and DAP matrix materials to develop polymer composite materials with self-healing properties The macrocapsules were produced by coating polystyrene (PS) sacrificial foam beads with raw ceramic slurry, followed by sintering to convert the liquid phase into a solid ceramic shell. Moreover, FTIR, TGA/DTA, and DSC analyses were performed. According to the thermal analysis results, DAP resin can effectively function as a healing agent up to approximately 340 °C. In addition, quasi-static compression tests were applied to composite specimens. After the first cycle, up to 69% healing efficiency was obtained in the epoxy matrix composite and 63.5% in the DAP matrix composite. Upon reloading, the second-cycle performance measurements showed healing efficiencies of 56% for the DAP matrix composite and 58% for the epoxy matrix composite. Full article

Majority of commercial L-asparaginase (L-ASNase) activity assays are based on coupled enzymatic reaction, which converts aspartate into pyruvate, subsequently reacting with the probe to form a stable chromophore, which can be detected spectrophotometrically. However, in complex biological samples this method can be inaccurate due to poor optical transparency or presence of compounds interfering with the coupled enzyme reaction–for this kind of cases alternative methods have been suggested. Here we suggest a strategy to rationally pick a method of choice in a variety of situations, taking into consideration the upsides and downsides of each method. A high-throughput fluorometric assay employing the substrate Asp-AMC was rigorously validated for L-ASPNase activity screening. Aassay performance is evaluated in complex biological matrices, including bovine serum, whole and diluted human blood, and finally the mouse blood and liver homogenates samples obtained from pharmacokinetic studies. This comprehensive validation process ensures the reliability and applicability of the assay for assessing L-asparaginase activity in diverse and physiologically relevant environments. Potential interfering factors and matrix effects were addressed, and assay conditions were optimized for each matrix. The optimized assay was employed to screen various L-asparaginase types (intracellular L-ASNases type I RrA, periplasmic L-ASNases type II EcA and EwA) and ASPNase formulations (conjugates with polyamines or polyelectrolyte complexes), comparing their kinetic parameters and stability. Fourier-transform infrared (FTIR) spectroscopy was further employed to investigate the fine features of molecular mechanisms of L-asparaginase catalysis. FTIR spectra of Asn during hydrolysis were analyzed in buffer solutions and in complex biological matrices, such as blood sample or liver homogenates which is crucial in the context of pharmacokinetic research. This combined fluorometric and FTIR approach provides a powerful platform for optimizing L-ASNase formulations and therapeutic strategies for ALL. Based on the results obtained we have developed a strategy to choose an approach for L-Asparaginase activity assessment for a variety of difficult situations when dealing with complex biological samples. Full article

The Carajás Mineral Province hosts one of the world’s most extensive sulfide-bearing copper belts. These deposits are typically covered by thick regolith, including gossans, laterites, colluviums, and soil, which can be used as important exploration indicators. In some cases, these covers can be mined alongside the parent hypogene ore. Therefore, accurate identification of copper-bearing minerals is essential for selecting the most appropriate metallurgical techniques. This study investigated the saprolite horizon overlying the Alvo 118 deposit, where the parent rocks are chloritites hosting copper-bearing hypogene sulfides, partially altered to an immature gossan. Saprolite formation was primarily controlled by the weathering of chlorite, mostly converted into kaolinite, with smectite and vermiculite serving as intermediates, forming a typical lower saprolite association. During weathering, iron released from chlorite and indirectly by vermiculite and smectite contributed to the formation of ferrihydrite, goethite, and hematite. Magnetite octahedrons, relics of the hypogene ore, pseudomorphic phases, are embedded in the clay mineral matrix. While FTIR analysis of kaolinite showed no evidence of copper retention, Mössbauer spectroscopy enabled the quantification of iron-bearing minerals, revealing a strong correlation between CuO contents and goethite and ferrihydrite. These results suggest that goethite and ferrihydrite may be the main copper carriers in the deposit, consistent with findings from similar deposits. Weak acid leaching is proposed as the most effective technique for copper extraction from this mineralization type. Full article

Piezo-driven compliant actuators capable of out-of-plane displacement from the substrate are urgently required in the fields of micro/nano manipulations and active optics, where compact size and low-profile configurations are often critical. In this paper, a two-stage amplification mechanism is developed by orthogonal series connection of a bridge-type mechanism and a Scott-Russell mechanism, for the sake of a large amplification ratio and high stiffness. The low-profile configuration is realized by horizontally mounting the piezoelectric actuator within the planar bridge-type amplification mechanism. The bridge-type mechanism initially amplifies the output displacement of the piezoelectric actuator. A compound guiding mechanism at the output end significantly enhances the equivalent stiffness and constrains parasitic displacements of the bridge-type mechanism. The second-stage Scott–Russell mechanism, further amplifies and converts the in-plane displacement into out-of-plane motion. The kinematic and static model of the developed mechanism is established using the compliance matrix method, enabling precise prediction of the amplification ratio and input/equivalent stiffness. Finite element simulations and experimental tests on the prototype validate the modeling accuracy and mechanical performance of the proposed low-profile amplification mechanism, demonstrating a large amplification ratio of 15.70, a high resonant frequency of 312.50 Hz, and a load-bearing capacity up to 20 N. Full article

Anaerobic digestion (AD) converts organic waste into methane-rich biogas but often faces performance issues due to organic acid and ammonium nitrogen accumulation. This hinders methanogen growth and reduces methane production. Recent studies show that incorporating conductive materials (CMs) into the AD matrix can mitigate these issues by facilitating electron transfer between microorganisms. This process accelerates the oxidation of organic acids and ammonium ions, enhancing methane recovery. The effectiveness of CMs depends on their type, porosity, surface morphology, and conductivity, which foster a symbiotic microbial community. This comprehensive review paper aimed to (i) describe the influence of CMs on the growth and enrichment of the AD microbial community, (ii) quantify the enhancement of biodegradation and methane generation, and (iii) observe syntrophic interactions and interspecies electron transfer. The review also summarized the impact of different conductive materials on methane generation and the effect of operational parameters, e.g., dose, size, and external voltage application, on the conductive electrodes. The study summarized that the different conductive materials have different influences, and their application in the AD matrix has to be realistic based on availability and economic benefits. Full article