Search Results (6,427)

Quinone/hydroquinone couples play a crucial role in a variety of biochemical processes and chemical syntheses. Extending from our previous work, a practical dataset including the thermodynamic driving forces of 12 chemical processes for 118 quinone/hydroquinone couples accepting or releasing two hydrogen atoms in DMSO is established. The dataset serves as a foundation for assessing and discussing the thermodynamic capabilities of hydroquinones acting as two-hydrogen-atoms antioxidants or radical quenchers, quinones and semiquinone radicals acting as hydrogen atoms abstractors, and quinone/hydroquinone couples acting as dehydrogenation and hydrogenation reagents. The fundamental thermodynamic knowledge is expected to further promote the broader application of quinone/hydroquinone couples in the field of chemical antioxidation and redox reactions. Full article

The coastline is a constantly evolving boundary between land and sea, shaped by natural forces and human activities. Given its significant ecological and economic value, this zone faces increasing pressures, highlighting the need for continuous monitoring and improved understanding to support sustainable management. This study analyses the spatial and temporal changes along the Al Qunfudhah coastline from 1984 to 2020. Using a combination of multi-temporal Landsat satellite images and geographic information system tools—specifically the digital shoreline analysis system—the research tracks changes over time. Shoreline positions were accurately extracted using automated methods, particularly the Canny edge detection algorithm. Over the 36-year period, analysis using the linear regression rate (LRR) and end point rate (EPR) methods revealed a general pattern of slight shoreline advancement. The highest rates of accretion were recorded at 12.43 m/year (LRR) and 13.36 m/year (EPR), with average rates of 3.63 m/year and 4.17 m/year, especially in the northern region where a corniche road was developed along the coast. Conversely, the most significant erosion occurred near the boat port, with maximum rates reaching −24.4 m/year (LRR) and −20.9 m/year (EPR) and average rates of −1.23 m/year and −1.08 m/year. These results offer valuable insights into the factors driving coastal changes and provide a scientific foundation for making informed, sustainable decisions about the future of the Al Qunfudhah coastline. Full article

Digitalization and greening are two fundamental forces shaping the current technological revolution and industrial transformation, serving as key pathways for nations to achieve sustainable development goals. Drawing on panel data from 30 Chinese provinces from 2012 to 2022, this study constructs indicators of digitalization and greening from the perspectives of data empowerment and technological efficiency improvement and examines how their synergistic development influences industrial structure optimization. The findings reveal the following: (1) although the overall synergy between digitalization and greening has steadily increased, regional disparities persist, displaying an “East strong–West weak” pattern, with inter-regional differences being the primary source of overall imbalance; (2) through the mediating role of environmental regulation, the coordinated advancement of digitalization and greening exerts a significant positive effect on industrial structure optimization; (3) heterogeneity analysis indicates a gradient empowerment effect, showing that the impact of digitalization–greening synergy on industrial structure optimization follows a “West > Central > East” pattern. These results provide both theoretical and empirical evidence for understanding how digitalization and greening jointly drive sustainable development. The study offers practical insights for guiding traditional industries to integrate into circular economy systems through “digitalization + greening” transformation and recommends that governments adopt differentiated strategies tailored to local conditions, enhance digital infrastructure, promote green initiatives, deepen reforms, and innovate regulatory frameworks to foster the synergistic advancement of digitalization and greening. Full article

As core pieces of transport equipment in longwall mining systems, scraper conveyors operate under extremely harsh and dynamic loading conditions. Their operational reliability and service life primarily depend on the performance of critical components within their drive systems, particularly the support bearings. However, complex and often unpredictable load spectra (such as severe impacts, vibrations, and contaminant ingress) pose significant challenges to the dynamic behavior and longevity of these bearings. Traditional static analysis fails to capture their true operating state, as it neglects transient effects, varying contact angles, and internal vibration excitation. This study conducts a comprehensive dynamic analysis of angular contact ball bearing 7205C to elucidate its dynamic response under actual operating conditions of scraper conveyors. Based on Hertzian elastic contact theory and bearing dynamics theory, the comprehensive stiffness of the angular contact ball bearing is derived, and the effects of axial force, rotational speed, and mass eccentricity on bearing performance are analyzed. The findings are expected to provide a theoretical foundation for optimizing bearing selection, predicting service life, and enhancing the overall reliability of mining machinery. Full article

The origin of life remains one of the most profound and enduring enigmas in the biological sciences. Despite substantial advances in prebiotic chemistry, fundamental uncertainties persist regarding the precise mechanisms that enabled the emergence of the first cellular entity and, subsequently, the foundational branches of the tree of life. After examining the core principles that define living systems, we propose that life emerged as a novel property of a prebiotically assembled system—formed through the integration of distinct molecular worlds, defined as sets of structurally and functionally related molecular entities that interact via catalytic, autocatalytic, and/or self-assembly processes. This emergence established a permanent system–process duality, wherein the system’s organization and its dynamic processes became inseparable. Upon acquiring the capacity to replicate and mutate its genetic program, this primordial organism initiated the evolutionary process, ultimately driving the diversification of life under the influence of evolutionary forces and leading to the formation of ecosystems. The challenge of uncovering the origin of life and the emergence of biodiversity is not solely scientific, it requires the integration of empirical evidence, theoretical insight, and critical reflection. This work does not claim certainty but proposes a perspective on how life and biodiversity may have arisen on Earth. Ultimately, time and scientific inquiry will determine the validity of this view. Full article

Species are disappearing worldwide and the expectation is that this will increase in the future. This review summarizes information on the reasons for the global reduction in biodiversity and what might happen in the future. The literature indicates that the most important factors responsible for this are changes in climate and land use. As changes in land use result in the destruction of natural habitats, they are thought to be the prime driver in the future. Climate change is, however, also often cited as a major driving force. To reduce the effect of climate change on the decline in biodiversity, it is important to know, how climate change affects the abundance and distribution of species. A particular emphasis should be placed not only on conserving specific species but also the environment and communities they live in. In addition, there are many other factors that might play a role, e.g., overexploitation, eutrophication and the introduction and spread of invasive non-native species. Full article

A general relativistic model of an astrophysical hypermassive extremely magnetized ultra-compact self-bound quark–gluon plasma (QGP: ALICE/LHC) object that is supported against its ultimate gravitational implosion by the simultaneous action of the vacuum polarization driven by nonlinear electrodynamics (NLED: ATLAS/LHC: light-by-light scattering)—the vacuum “awakening”—and the asymptotic freedom, a key feature of quantum chromodynamics (QCD), is presented. These QCD stars can be the final figures of the equilibrium of collapsing stellar cores permeated by magnetic fields with strengths well beyond the Schwinger threshold due to being self-bound, and for which post-supernova fallback material pushes the nascent remnant beyond its stability, forcing it to collapse into a hybrid hypermassive neutron star (HHMNS). Hypercritical accretion can drive its innermost core to spontaneously break away color confinement, powering a first-order hadron-to-quark phase transition to a sea of ever-freer quarks and gluons. This core is hydro-stabilized by the steady, endlessly compression-admitting asymptotic freedom state, possibly via gluon-mediated enduring exchange of color charge among bound states, e.g., the odderon: a glueball state of three gluons, or either quark-pairing (color superconductivity) or tetraquark/pentaquark states (LHCb Coll.). This fast—at the QGP speed of sound—but incremental quark–gluon deconfinement unbinds the HHMNS’s baryons so catastrophically that transforms it, turning it inside-out, into a neat self-bound QGP star. A solution to the nonlinear Tolman–Oppenheimer–Volkoff (TOV) equation is obtained—that clarifies the nonlinear effects of both NLED and QCD on the compact object’s structure—which clearly indicates the occurrence of hypermassive QGP/QCD stars with a wide mass spectrum ($0\lesssim {\mathrm{M}}_{\mathrm{Star}}^{\mathrm{QGP}}\lesssim$ 7 M_⊙ and beyond), for star radii ($0\lesssim R_{\mathrm{Star}}^{\mathrm{QGP}}\lesssim 24$ km and beyond) with B-fields (${10}^{14}\le {\mathrm{B}}_{\mathrm{Star}}^{\mathrm{QGP}}\le {10}^{16}$ G and beyond). This unexpected feature is described by a novel mass vs. radius relation derived within this scenario. Hence, endowed with these physical and astrophysical characteristics, such QCD stars can definitively emulate what the true (theoretical) black holes are supposed to gravitationally do in most astrophysical settings. This color quark star could be found through a search for its eternal “yo-yo” state gravitational-wave emission, or via lensing phenomena like a gravitational rainbow (quantum mechanics and gravity interaction), as in this scenario, it is expected that the light deflection angle—directly influenced by the larger effective mass/radius (${\mathrm{M}}_{\mathrm{Star}}^{\mathrm{QGP}}\left(B\right)$, ${\mathrm{R}}_{\mathrm{Star}}^{\mathrm{QGP}}\left(B\right)$) and magnetic field of the deflecting object—increases as the incidence angle decreases, in view of the lower values of the impact parameter. The gigantic—but not infinite—surface gravitational redshift, due to NLED photon acceleration, makes the object appear dark. Full article

Model Predictive Control (MPC) predicts the vehicle’s motion within a fixed time window, known as the prediction horizon, and calculates potential collision risks with obstacles in advance. It then determines the optimal steering input to guide the vehicle safely around obstacles. For example, when a sudden obstacle appears, sensors detect it, and MPC uses the vehicle’s current speed, position, and heading to predict its driving trajectory over the next few hundred milliseconds to several seconds. If a collision is predicted, MPC computes the optimal steering path among possible avoidance trajectories that are feasible within the vehicle’s dynamics. The vehicle then follows this input to steer away from the obstacle. In the proposed method, MPC is combined with Adaptive Artificial Potential Field (APF). The APF dynamically adjusts the repulsive force based on the distance and relative speed to the obstacle. MPC predicts the optimal driving path and generates control inputs, while the avoidance vector from APF is integrated into MPC’s constraints or cost function. Simulation results demonstrate that the proposed method significantly improves obstacle avoidance response, steering smoothness, and path stability compared to the baseline MPC approach. Full article

Continental high water-cut reservoirs commonly exhibit strong heterogeneity, high viscosity, and insufficient reservoir drive, which has motivated the deployment of polymer-based composite chemical flooding, such as surfactant–polymer (SP) and alkali–surfactant–polymer (ASP) processes. However, conventional experimental techniques have limited ability to resolve intermolecular forces, and the coupled mechanism linking “formulation composition” to “microstructural evolution” remains insufficiently defined, constraining improvements in field performance. Here, scanning electron microscopy (SEM), backscattered electron (BSE) imaging, and molecular dynamics (MD) simulations are integrated to systematically investigate microstructural features of polymer composite systems and the governing mechanisms, including hydrogen bonding and electrostatic interactions. The results show that increasing the concentration of partially hydrolyzed polyacrylamide (HPAM) promotes hydrogen bond formation and the development of network structures; a moderate amount of surfactant strengthens interactions with polymer chains, whereas overdosing loosens the structure via electrostatic repulsion; the introduction of alkali reduces polymer connectivity, shifting the system toward an ion-dominated dispersed morphology. These insights provide a mechanistic basis for elucidating the behavior of polymer composite formulations, support enhanced chemical flooding performance, and ultimately advance the economic and efficient development of oil and gas resources. Full article

Ternary organic photovoltaics (OPVs) are considered as the next step beyond binary systems, aiming to achieve synergistic improvements in absorption, energetic alignment, and charge transport. However, despite their conceptual appeal, most ternary blends do not outperform binary counterparts, particularly under indoor illumination where photon flux and carrier dynamics impose strict limitations. To comprehensively understand this discrepancy, multiple ternary systems were systematically examined to ensure that the observed behaviors are representative rather than case specific. In this study, we systematically investigate this discrepancy by comparing representative donor–donor–acceptor (D–D–A) and donor–acceptor–acceptor (D–A–A) systems under both AM 1.5G and TL84 lighting. In all cases, the broadened absorption fails to yield effective photocurrent; instead, redundant excitations, reduced driving forces for charge separation, and disrupted percolation networks collectively diminish device performance. Recombination and transient analyses reveal that the third component often introduces energetic disorder and trap-assisted recombination instead of facilitating beneficial cascade pathways. Although the film morphology remains smooth, interfacial instability under low-light conditions further intensifies performance losses. The inclusion of several systems allows the identification of consistent mechanistic trends across different ternary architectures, reinforcing the generality of the conclusions. This work establishes a mechanistic framework linking molecular miscibility, energetic alignment, and percolation continuity to device-level behavior, clarifying why ternary strategies rarely deliver consistent efficiency improvements. Ultimately, indoor OPV performance is determined not by spectral breadth but by maintaining balanced charge transport and stable energetic landscapes, which represents an essential paradigm for advancing ternary OPVs from concept to practical application. Full article

In recent years, as a new driving force for building a modern industrial system, new-quality productive forces have emerged as a key factor in advancing the high-end, intelligent, and green development of industrial chains. This study selects panel data from 31 provincial-level administrative regions in China (excluding Hong Kong, Macau, Taiwan, and the Tibet Autonomous Region) for the period 2011–2021 as the research sample. A regression analysis model is constructed from three dimensions—overall effect, moderating effect, and spatial spillover effect—to empirically examine the impact of new-quality productive forces on industrial chain modernization. The results indicate that new-quality productive forces exert a stable and significant promotional effect on industrial chain modernization and generate an indirect positive impact by driving green technological innovation. Full article

In response to global sustainability challenges, this study investigates how Digital New-Quality Productive Forces (DNQPF), which integrate digitalization with green innovation, contribute to Sustainable Industrial Structural Upgrading (SISU) in China. Using panel data from 30 provinces spanning 2011–2023, a multidimensional DNQPF index was constructed, and a comprehensive econometric framework was applied, including two-way fixed effects, mediation and moderation analyses, Hansen threshold models, and Spatial Durbin models. The results indicate that DNQPF significantly enhances SISU (β = 0.291, p < 0.01), with household consumption upgrading serving as the key mediating channel. Regional heterogeneity is evident: Eastern provinces show strong effects (β = 0.295, p < 0.01) and central provinces exhibit catch-up potential (β = 0.467, p < 0.10), while the Western and Northeastern regions display insignificant effects due to digital infrastructure disparities. The threshold effects reveal diminishing returns beyond a DNQPF level of 0.239 (coefficient decline from 0.518 to 0.323, p < 0.01), a marketization level of 6.181, and an innovation level of 9.520. Spatial analysis further confirms positive spillovers (direct effects = 0.282–0.320; indirect effects = 0.260–1.317; p < 0.05). These findings enrich endogenous growth theory by integrating digital and green development into emerging economies and underscore DNQPF’s role in advancing SDG 9 (Industry, Innovation, and Infrastructure) and SDG 12 (Responsible Consumption and Production). Coordinated digital–green strategies, institutional reforms, and inclusive infrastructure are therefore critical for achieving sustainable industrial transformation in China and beyond. Full article

Global ecosystems have undergone significant degradation and deterioration, making the identification of ecosystem changes essential for promoting sustainable development and enhancing quality of life. Hami City, a representative region characterized by the complex “desert–oasis–mountain” ecosystem in Xinjiang, China, provides a critical context for examining ecosystem changes in extremely arid environments. This study utilizes remote sensing data alongside the Revised Wind Erosion Equation and Revised Universal Soil Loss Equation models to analyze the transformations within the desert–oasis ecosystems of Hami City and their driving forces. The findings reveal that (1) over the past 24 years, there have been substantial alterations in the ecosystem patterns of Hami City, primarily marked by an expansion of cropland and grassland ecosystems and a reduction in desert ecosystems. (2) Between 2000 and 2023, there has been an upward trend in Fractional Vegetation Cover, Net Primary Productivity, and windbreak and sand fixation amount in Hami City, whereas soil retention has shown a declining trend. (3) The overall ecosystem change in Hami City is moderate, encompassing 61.85% of the area, with regions exhibiting positive change comprising 16.79% and those with negative change comprising 21.33%. (4) Temperature, precipitation, and evapotranspiration are the primary drivers of ecosystem change in Hami City. Although the overall changes in ecosystems in Hami City have shown an improving trend, significant spatial heterogeneity still exists. The natural climatic conditions of Hami City constrain the potential for further ecological improvement. This study enhances the understanding of ecosystem change processes in extremely arid regions and demonstrates that strategies for mitigating or adapting to climate change need to be implemented as soon as possible to ensure the sustainable development of ecosystems in arid areas. Full article

The name Green Chemistry was coined in 1996 to point out the development of chemical substances and sustainable processes that reduce the formation of toxic products for the environment and humans. The urgent need to bring down the negative effects of the chemical industry to safeguard human health has been the driving force behind green chemistry and the need to respect the United Nations Sustainable Development Goals. This approach allows to increase the effectiveness of synthetic methods, to develop safer, less toxic, and environmentally sustainable chemicals. In this context, microwave-assisted organic reactions revolutionized the chemical synthesis; as a matter of fact, microwave chemistry led to a low environmental impact of the used solvents, and, over the years this overture has become the method of choice in synthetic chemistry. This review highlights in detail the main features of microwaves. Full article

Ultra-deep fractured tight sandstone reservoirs are key targets for natural gas development, where gas flow is controlled by pore structure, capillary forces, and water saturation. Using the ultra-deep tight sandstones from the Tarim Basin as study object, this paper investigates the gas flow behavior in matrix and fractured cores under high-temperature, high-pressure, and various water saturation conditions. The controlling factors of gas flow are investigated through scanning electron microscopy, casting thin-section, and high-pressure mercury intrusion measurements. The results show that increasing the water saturation can significantly reduce the permeability. The permeability of matrix and fractured cores decreases by 71.15% and 79.67%, respectively, when water saturation reaches 50%. The gas slippage is negligible, but the effect of gas threshold pressure is significant, which is primarily controlled by the pore structure and water saturation. The threshold pressure gradient of gas flow ranges from 0.0004 to 0.8762 MPa/cm, with the matrix cores exhibiting values approximately 13.21 times higher than the fractured cores. The water phase preferentially occupies the larger pores, forcing gas flow to rely on the finer pores. The pores with a maximum radius of 0.21 μm require 0.66 MPa of driving pressure for gas, whereas pores with a median radius of 0.033 μm require 4.18 MPa. The fracture networks can significantly reduce the lower limit for gas flow, serving as the key flow channels for the efficient development of ultra-deep tight sandstone gas. These findings not only reveal the gas flow mechanisms under water invasion but also provide theoretical and practical guidance for enhancing gas recovery from ultra-deep tight sandstone reservoirs. Full article