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Mixing in biogas fermenters is complex due to the non‐Newtonian rheology of biogenic substrates, which exhibit both pseudoplasticity and elasticity. It is yet unclear how these non‐Newtonian properties affect propeller flows and the mixing behavior in fermenters. Therefore, propeller flows in Newtonian as well as shear‐thinning inelastic and elastic fluids are compared numerically and validated against particle image velocity (PIV) data. Elastic normal stresses lead to an increase of pumping rates in the laminar regime and a suppression of the formation of a propeller jet in the transitional regime. Thus, flow rates are severely overestimated by the inelastic, shear‐thinning model in this regime. The results indicate that elasticity is critical for an accurate modeling of flows of biogenic substrates. [ABSTRACT FROM AUTHOR]

The potential of comprehending and managing microscale flows to enhance energy processes, especially in heat transfer and propulsion applications, remains largely untapped particularly for supercritical fluids, which have gained increased interest over the past years due to the higher power and thermodynamic efficiencies they provide. This work, therefore, presents the first comprehensive, open-source dataset carefully curated and structured for studying microconfined high-pressure transcritical fluid channel flows under various regimes. Particularly, the dataset contains 18 direct numerical simulations of carbon dioxide at different bulk pressures and velocities confined between differentially-heated walls. For all cases, the thermodynamic conditions selected impose the fluid to undergo a transcritical trajectory across the pseudo-boiling region. The data collection comprises an array of physical quantities that enable comprehensive parametric analyses spanning laminar, transitional, and turbulent flow regimes. This data repository is poised to provide access to the detailed study and modeling of the complex flow physics observed in high-pressure transcritical fluids, especially those closely linked to improving microfluidics performance. [ABSTRACT FROM AUTHOR]

Efficient laser-driven plasma acceleration of ion beams requires precision control of the target–plasma profile, which is crucial to optimize the laser energy transfer. Along the laser propagation direction, this can be achieved by tailoring the temporal structure of the laser pulse. We show for the first time that frequency-doubling of a short pulse (hundreds-femtosecond range) petawatt-class mixed-glass laser system, which results in temporal intensity contrast enhancement, enables surface and volumetric laser–energy coupling, and the acceleration of proton beams from few-nanometer-thick foil targets. Experimentally, maximum ion energies and laser-to-proton energy conversion efficiencies were found to be both maximized at optimum laser and target conditions manifested when the normalized target density nearly equalizes the normalized laser vector potential, which is in agreement with theory and simulations. These signatures are recognized as a unique indication of the interaction between ultra-intense laser pulses with high temporal intensity contrast and ultra-thin nanometer-scale targets. Transverse modulations of accelerated proton beams in the form of bubble- and ring-like structures measured in the thinnest targets provide additional evidence of volumetric laser-driven particle acceleration regimes and transitional features in ultra-thin foil targets specific to laser–plasma interactions characterized by a high temporal intensity contrast. These results open avenues in the generation of high contrast laser pulses from short-pulse-femtosecond petawatt mixed-glass laser systems and demonstrate the feasibility of this technique for applications requiring high laser intensity contrast with high efficiency. [ABSTRACT FROM AUTHOR]

The Democrat Party’s (DP) decade-long period in office ended with a military intervention on 27 May 1960. In the coup declaration, the National Unity Committee (NUC) announced that Turkey would remain loyal to its North Atlantic Treaty Organization (NATO) and Central Treaty Organization (CENTO) alliances as well as Turkey’s other international commitments. Turkey’s economic and military dependence on the USA (United States of America) also remained unchanged, contrary to the expectations of the Kemalists, leftists, and anti-DP circles who had mythicized the NUC’s role in Turkey’s independence from the USA. This study examines primary sources such as US archival records and the records of the Turkey’s constituent assembly and provisional government. It analyses the diplomatic relations between Turkey and the USA during this period and shows how Turkey’s dependence on the USA continued through economic and military assistance. [ABSTRACT FROM AUTHOR]

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Granular flows are ubiquitous in nature with single flows traversing a wide range of dynamic conditions from initiation to deposition. Many of these flows are responsible for significant hazards and can generate remotely detectable seismic signals. These signals provide a potential for real‐time flow measurements from a safe distance. To fully realize the benefit of seismic measurements, basal‐granular forces must be linked to macroscopic internal flow dynamics across a wide range of flow conditions. We utilize discrete element simulations to observe dry and submerged granular flows under plane‐shear and inclined‐flow configurations, relating bulk kinematics to basal‐force distributions. We find that the power and frequency of force fluctuations scale with non‐dimensional shear rate (I). This scaling tracks three pre‐established regimes that are described by μ(I) rheology: (a) an intermittent particle rearrangement regime, where basal forces are dominated by low frequencies; (b) an intermediate regime where basal forces start to increase in frequency while showing correlations in space and (c) a fully collisional regime where the signal is nearly flat up to a cutoff frequency. We further identify a newly defined fourth regime that marks a "phase change" from the intermediate to collisional regime where increases in basal force fluctuations with increasing shear rates stalls as the granular bed dilates, partially destroying the contact network. This effort suggests that basal forces can be used to interpret complex granular processes in geophysical flows. Plain Language Summary: Debris flows, pyroclastic flows, and debris avalanches are natural granular flows that have the ability to generate seismic signals. These signals can be recorded from safe distances away, providing a record of how these flows interact with the surface. Nevertheless, it is difficult to interpret these signals in terms of flow conditions. To better understand how to relate the forces exerted by these flows back to flow conditions, we perform granular flows, recording the forces exerted on a simulated substrate. Simulated flow conditions resemble those that correspond to the beginning of an event, when the flow is slow moving, to conditions that are like that of a fast moving well developed flow. We find that the forces exerted on the ground have the ability to tell researchers important flow information, such as how stresses are transmitted internally in the flow. Moreover, these basal forces record when the collection of grains changes from a liquid‐like to a gas‐like flow, where individual grains are no longer in prolonged contact, but begin to collide and bounce off one another, like gas‐molecules. These results show that complex information can be encoded in the interactions between an overriding flow and it's substrate. Key Points: Discrete element simulations of granular flows in plane‐shear and inclined‐slope flow configurations reveal bed contact force distributionsBasal forces record changes in flow regime correlating with non‐dimensional shear rate (inertial number) independent of flow configurationBasal forces record a transitional regime from liquid‐like to gas‐like granular dynamics in which memory stored via elastic contacts are erased [ABSTRACT FROM AUTHOR]

Nationalists believed that Ireland had not thrived economically under the Union. This article explores economic policymaking under the 1922 Provisional Government which administered the 26 counties during the one-year transition phase from British to Irish Free State jurisdiction. It is a case study which examines the fate of pre-independence economic programmes; the reorganisation of the economic portfolios of the civil service; the handling of immediate economic problems; as well as the formulation of plans and priorities for Ireland's future. The Provisional Government faced an unprecedented array of internal and external problems, in particular the economic depression and deflation in the wake of the First World War (1914–1918); the economic damage of the Irish War of Independence (1919–1921); and the divisive and violent Irish Civil War (1922–3) - the result of rupture in the main nationalist political party, Sinn Féin, over acceptance of the Anglo-Irish Treaty settlement, which provided for the creation of the Irish Free State as a dominion rather than as a fully sovereign republic. Depspite these setbacks, the Provisional Government needed to enforce its authority and demonstrate its ability to govern by being seen to competently address economic issues. [ABSTRACT FROM AUTHOR]

The mechanisms driving the transition to turbulence in pulsatile flows are not well understood. Prior studies in this domain have noted the dynamics of this flow regime to depend on the mean Reynolds number, pulsation frequency (i.e., Womersley number), and inflow pulsatile waveform shape. Conflicting findings, particularly regarding the role of the Womersley number on the critical Reynolds number and the development of turbulence, have been reported. The discord has primarily been observed for flows, with Womersley numbers ranging from 4 to 12. Hence, in this work, we use particle image velocimetry to explore the effects of the Womersley number within this 4–12 range on the dynamics of the pulsatile transition. Eighteen test cases were captured using six mean Reynolds numbers (range 800–4200) and five Womersley numbers. Turbulent kinetic energy, turbulence intensity (TI), and phase lag were computed. Our results indicated that the critical Reynolds number was roughly independent of the Womersley number. At high Womersley numbers, the TI trend maintained lower pulsatility, and the flow was observed to mimic a steady transitional flow regime. A plateau of the TI-velocity and TI-acceleration phase lag was observed at a Womersley number of 8, highlighting that this may be the critical value where further increases to the Womersley number do not alter the transition dynamics. Furthermore, this suggests that the phase lag may provide a universal indicator of the specific influence of the Womersley number on transition for a given flow. Overall, these findings elucidate critical details regarding the role of the Womersley number in the transition to turbulence. [ABSTRACT FROM AUTHOR]

The 2011 Arab Spring uprisings are often portrayed as a wave of failed revolutions that devolved rapidly into anarchic violence. Yemen and Libya appear to illustrate this dynamic par excellence, as interim governments collapsed in the face of violence, war, and humanitarian disasters by 2014. Although studies of these revolutions have proliferated in recent years, the fuller range of outcomes emerging from the Arab Spring at the local level and in everyday life have comprised a theoretical and empirical black box. Based on the grounded analysis of ethnographic data from Yemen and Libya during the post-Arab Spring interim periods (2012–2013), this study argues that although the 2011 revolutions failed to achieve their major goals, they succeeded in breaking down normative forms of incumbent authoritarian power across major urban centers. As a result, activists and ordinary citizens gained what we call newfound "civic opportunities" to make political claims in Yemen and Libya's emergent civic spheres. Participants did so by repurposing their built environment for artistic expression, engaging in peaceful collective action, and publicly commemorating the victims and heroes of anti-regime resistance. While civic opportunities were later eclipsed by violence, we argue that revolutions failing to instigate democratic change from "above" can nevertheless create meaningful civic opportunities for democratic practices from "below." The study concludes by suggesting how this mobilization matters for future waves of protest and democratization, and for the scholarly investigation of revolution outcomes more generally. [ABSTRACT FROM AUTHOR]

In this work, forced convection experiments were carried out to investigate the variation of heat transfer and pressure drop inside a uniformly heated circular duct fitted with full-length spring tape inserts of varying spring ratios in a transition flow regime. Air was used as the working fluid medium, and experiments were conducted for three constant heat fluxes of 2, 3, and 4 kW-m−2 with Reynolds numbers varied from 502 to 10936 to cover all three flow regimes. For a plain channel heated with 2 kW/m2 of heat flux, the transition begins at a Reynolds number of 2897 and terminates at a Reynolds number of 3783 which brings the transition Reynolds number width of 886. For the same heat flux, a channel with spring tape having a spring ratio of 3, the transition begins at Reynolds number 661 and ends at 1734 while for the case of spring ratio 5, the transition begins at 1305 and ends at 2226. For constant heat flux conditions, a decrease in the spring ratio results in the early onset of transition and which in turn increased the transition length. Predictive Nusselt number and friction factor correlations for different flow regimes have also been presented. [ABSTRACT FROM AUTHOR]

Seismic-wave scattering is observed, to variable degrees, on Earth, its moon and Mars. Current scattering models and data processing typically rely on two end-member phenomena: weak, single- or multiple-scattering events (ballistic) on the one hand, or intense scattering such that the wavefield retains no path information or bearing on its origin (diffuse).This study explores the existence of scattering behaviour intermediate between these end-members, as well as the properties of heterogeneous media that facilitate a transition between them. We apply multiscale entropy and frequency-correlation analysis to seismic coda, and observe a distinct transitional behaviour is present within a part of the investigated parameter space. Analysis of terrestrial, lunar and Martian seismograms further demonstrate the applicability of these new methods across a wide range of scattering behaviours, while also highlighting their shortcomings. Results from the planetary data indicate partially non-diffuse behaviour and low complexity within specific bandwidths of lunar wavefields, potentially contradicting the current paradigm that lunar wavefields are diffuse, and require continued study. Furthermore, Martian seismograms are shown to possess greater statistical entropy than lunar seismograms and diffuse energy properties, yet still display distinct phase arrivals, suggesting substantial scattering and transitional scattering behaviour on Mars. The robust, comparative nature of multiscale entropy and frequency-correlation analysis, applied to idealised simulation as well as three separate planetary bodies, provides a promising framework for future exploration of scattered wavefields across ballistic, transitional and diffuse regimes, that complements existing methods. [ABSTRACT FROM AUTHOR]

A scarcity of studies about nanofluids' utilization in droplet formation inside microdevices currently hovers in the literature although potential applications of nanoparticles in a microfluidic environment are foreseen. For this purpose, experimentally assessing both nanofluid and microdroplet characteristics is fundamental. This work reports a series of experimental tests on the microdroplet formation of distilled water (DIW) and DIW-based aluminum oxide (Al2O3) nanofluid in a microfluidic T-junction. While water and nanofluid are used as the dispersed phase, mineral oil is used as the continuous phase. Microdroplet formation in the squeezing, transitional, and dripping regimes is characterized and scaling laws for the non-dimensional droplet volumes are presented. The effects of flow rate, capillary number, microchannel aspect ratio, and nanoparticle concentration are investigated. The addition of Al2O3 nanoparticles to the water is observed to have a major impact in the transitional regime (up to 40% increase), whereas in the dripping regime its influence is lower, with less than 10% difference. This was attributed to the nanofluid's enhanced interfacial tension and viscosity compared to the DIW, as well as possible adsorption at the surface. [ABSTRACT FROM AUTHOR]

This work examines the influence of body porosity on the wake past nominally two-dimensional rectangular plates of fixed width $D$ in the moderate range of Reynolds numbers $Re = UD/\nu$ (with $U$ the incoming velocity and $\nu$ the kinematic viscosity) between 15 000 and 70 000. With porosity $\beta$ defined as the ratio of open to total area of the plate, it is well established that as porosity increases, the wake shifts from the periodic von Kármán shedding behaviour to a regime where this vortex shedding is absent. This change impacts the fluid forces acting on the plate, especially the drag, which is significantly lower for a wake without vortex shedding. We analyse experimentally the transition between these two regimes using hot-wire anemometry, particle-image velocimetry and force measurements. Coherence and phase measurements are used to determine the existence of regular, periodic vortex shedding based on the velocity fluctuations in the two main shear layers on either side of the wake. Results show that, independent of $Re$ , the wake exhibits the classical Kármán vortex shedding pattern for $\beta but this is absent for $\beta >0.3$. In the intermediate range, $0.2 , there is a transitional regime that has not previously been identified; it is characterised by intermittent shedding. The flow alternates randomly between a vortex shedding and a non-shedding pattern and the total proportion of time during which vortex shedding is observed (the intermittency) decreases with increasing porosity. [ABSTRACT FROM AUTHOR]

This paper applies fractional calculus to a practical example in fluid mechanics, illustrating its impact beyond traditional integer order calculus. We focus on the classic problem of a rigid body rotating within a uniformly rotating container, which generates a liquid vortex from an undisturbed initial state. Our aim is to compare the time evolutions of the physical system in fractional and integer order models by examining the torque transmission from the rotating body to the surrounding liquid. This is achieved through closed-form, time-developing solutions expressed in terms of Mittag–Leffler and Bessel functions. Analysis reveals that the rotational velocity and, consequently, the vortex structure of the liquid are influenced by three distinct time zones that differ between integer and noninteger models. Anomalous diffusion, favoring noninteger fractions, dominates at early times but gradually gives way to the integer derivative model behavior as time progresses through a transitional regime. Our derived vortex formula clearly demonstrates how the liquid vortex is regulated in time for each considered fractional model. [ABSTRACT FROM AUTHOR]

Among the the existing studies of the 1917 food‐supply crisis none has examined in detail the role and impact of grain registration. This article fills that gap by investigating the implementation of grain registration in Penza province, thus adding to and complicating the increasingly decentered picture of food‐supply policy and its impact in 1917. This study asserts that a major turning point during 1917 was the poor Volga harvest, which contributed to the threat of a prolonged subsistence crisis in an intermediary province already enduring the collapse of critical resupply channels. In this context, initially ambivalent volost officials and peasants came to embrace grain registration in the post‐harvest period as a way to document a legitimate claim to receive grain. This article adds to our understanding of the variability of peasant agency exhibited during 1917. The main post‐harvest struggle was over competing interpretations of the registration process between volost and district officials. The latter were pressed by provincial and central superiors to increasingly utilize armed force, not to compel compliance with registration, but to hasten the delivery of grain to urban consumers. This study illustrates how the Provisional government's turn to state violence to establish its procurement authority was a function of how its policies, combined with deteriorating local conditions, produced competing entitlements to grain. Rather than a continuum of crisis in which Provisional government food‐supply policies repeatedly exacerbated crisis by failing to overlap with local demands and provoked resistance among grain producers and consumers, a combination of state and non‐state factors produced an economic environment in which the interests of both volost officials and peasants were served by key features of the state grain monopoly, especially grain registration. [ABSTRACT FROM AUTHOR]

Emerging research indicates that ground-level ozone (O3) has become a leading contributor to air quality concerns in many Chinese cities, with the Yangtze River Delta (YRD) region facing particular challenges. This study investigated the characterization of air pollutants in Wujiang, which is located within the YRD demonstration zone, during the warm season (April–September) of 2022. The contributions of emission and meteorology to O3 were identified, the O3-NOX-VOC sensitivities were discussed, and the VOC sources and their contributions to O3 formation were analyzed. A random forest model revealed that the high O3 concentration was mainly caused by a combination of increased emission intensity due to the resumption of work and production after the COVID-19 pandemic, along with adverse meteorological conditions. The results revealed more than 92% of the pollution days were related to O3 during the warm season, and the impact of O3 precursor emissions was slightly greater than that of the meteorological conditions. O3 formation was in the VOC-limited regime, and emission reduction strategies targeting VOCs, particularly aromatics such as toluene and xylene, have been identified as the most effective approach for mitigating O3 pollution. Changes in O3-NOX-VOC sensitivity were also observed from the VOC-limited regime to the transitional regime, which was primarily driven by variations in the NOX concentrations. The VOC source analysis results showed that the contributions of gasoline vehicle exhaust and diesel engine exhaust (mobile source emissions) were significantly greater than those of the other sources, accounting for 20.8% and 16.5% of the total VOC emissions, respectively. This study highlights the crucial role of mobile source emission control in mitigating O3 pollution. Furthermore, prioritizing the control of VOC emission sources with minimal NOX contributions is highly recommended within the VOC-limited regime. [ABSTRACT FROM AUTHOR]

Under the influence of climate change, the increasing occurrence of extreme weather events, such as heatwaves, has led to an enhanced frequency of ozone (O 3) pollution issues. In August 2022, the Sichuan Basin (SCB), a typical large-scale geographical terrain located in southwestern China, experienced the most severe heatwave in the last 20 years. The heatwave led to substantial disparities in O 3 levels across the region. Here, by integrating observations, machine learning, and numerical simulations, we aim to understand the diverse O 3 formation mechanisms in two megacities, Chengdu (western location) and Chongqing (eastern location). Observational data showed that Chengdu experienced a consecutive 17 d period of O 3 exceedance, in contrast to Chongqing, where O 3 concentrations remained below the standard. Meteorological and precursor factors were assessed, highlighting high temperatures, intense solar radiation, and overnight accumulative pollutants as key contributors to O 3 concentrations. The interplay of isoprene, temperature, and O 3 , alongside the observation-based box model and MEGAN simulations, underscored the significant role of intensified biogenic volatile organic compounds (BVOCs) in O 3 formation. Interestingly, Chongqing exhibited nearly double the BVOC emissions of Chengdu, yet contributed less to O 3 concentrations. This discrepancy was addressed through CMAQ-DDM (Decoupled Direct Method) simulations and satellite diagnosis by investigating the O 3 –NO x –VOC sensitivity. Notably, Chengdu displayed a VOC-driven sensitivity, while Chongqing showed a transitional regime. Moreover, the regional transport also played a pivotal role in the spatial divergence of O 3 pollution. Cross-regional transport predominantly influenced Chongqing (contributing ∼ 80 %), whereas Chengdu was mainly affected by the emissions within the basin. The local accumulated pollutants gave rise to the atmospheric oxidizing capacity, resulting in a substantial photochemical contribution to O 3 levels (49.9 ppbv h -1) in Chengdu. This comparison of the difference provides insights into the complex interplay of meteorology, natural emissions, and anthropogenic sources during heatwaves, guiding the necessity of targeted pollution control measures on regional scales. [ABSTRACT FROM AUTHOR]

We investigate numerically the propulsion characteristics of an oscillating foil undergoing coupled heave and pitch motion in a linearly density-stratified flow. A parameter space defined by the internal Froude number (1 ≤ Fr ≤ 10) and the maximum angle of attack (5° ≤ α0 ≤ 30°) is considered in our study. The results demonstrate a significant enhancement in both thrust production and propulsive efficiency due to the stratification influence. Notably, the highest efficiency exceeding 80 % is achieved under moderate stratification conditions, surpassing the performance observed in a homogeneous fluid. We attribute this optimum performance to the proper match between the stratification effect and foil kinematics, which gives rise to intense vortex interactions and sufficient wave-mean flow interactions in the near wake of the oscillating foil. Consequently, the energy is transferred towards wake structures to form a high-intensity momentum jet in close proximity to the foil's trailing edge, indicating efficient propulsion. Furthermore, we find that the stratifications within the moderate-to-strong transitional regime display a reduced dependence of propulsive efficiency on the maximum angle of attack, primarily due to the delaying and alleviating effects on dynamic-stall events. Such a mechanism enables the oscillating foil to maintain a satisfactory performance by sufficiently high angles of attack without the penalty of stall events. Based on our findings, we propose that animals or artificial vehicles utilising oscillatory propulsion can benefit from the presence of density stratification in the surrounding fluid. [ABSTRACT FROM AUTHOR]

Enhanced ozone (O3) pollution has emerged as a pressing environmental concern in China, particularly for densely populated megacities and major city clusters. However, volatile organic compounds (VOCs), the key precursors to O3 formation, have not been routinely measured. In this study, we characterize the spatial and temporal patterns of VOCs and examine the role of VOCs in O3 production in five cities (Dongying (DY), Rizhao (RZ), Yantai (YT), Weihai (WH), and Jinan (JN)) in the North China Plain (NCP) for two sampling periods (June and December) in 2021 through continuous field observations. Among various VOC categories, alkanes accounted for the largest proportion of VOCs in the cities. For VOCs, chemical reactivities, aromatic hydrocarbons, and alkenes were dominant contributors to O3 formation potential (OFP). Unlike inland regions, the contribution to OFP from OVOCs increased greatly at high O3 concentrations in coastal regions (especially YT). Model simulations during the O3 episode show that the net O3 production rates were 27.87, 10.24, and 10.37 ppbv/h in DY, RZ, and JN. The pathway of HO2 + NO contributed the most to O3 production in JN and RZ, while RO2 + NO was the largest contributor to O3 production in DY. The relative incremental reactivity (RIR) revealed that O3 formation in DY was the transitional regime, while it was markedly the VOC-limited regime in JN and RZ. The O3 production response is influenced by NOx concentration and has a clear daily variation pattern (the sensitivity is greater from 15:00 to 17:00). The most efficiencies in O3 reduction could be achieved by reducing NOx when the NOx concentration is low (less than 20 ppbv in this study). This study reveals the importance of ambient VOCs in O3 production over the NCP and demonstrates that a better grasp of VOC sources and profiles is critical for in-depth O3 regulation in the NCP. [ABSTRACT FROM AUTHOR]

A numerical framework based on the gas kinetic flux solver (GKFS) with unstructured meshes of triangle cells has been proposed and assessed in this work. Like conventional GKFS, the present scheme only updates the cell-average macroscopic conservative variables in time, thereby saving computational costs. At each cell interface, the numerical normal flux is computed with the GKFS scheme proposed by Liu et al. [J. Comput. Phys. 415, 109548 (2020)], in which the distribution functions at the surrounding points are reconstructed with the Grad's 13 moments (G13). Additionally, a solid wall boundary condition treatment has been proposed in the present G13-GKFS framework, which allows one to model from purely specular to perfectly thermalized solid walls. The present framework has been validated with the steady cylindrical Couette flow, the lid-driven cavity flow, the unsteady Rayleigh flow, and the rarefied flow around the NACA0012 airfoil test-cases, where good agreements are found with references for a quite wide range of flow regimes, from continuum to transitional flow regimes. [ABSTRACT FROM AUTHOR]

The Russian provisional government and Bolshevik regime, in their respective efforts to address and resolve the food-supply crisis of 1917-19, sought to modernize statevillage relations and mobilize peasant-citizens to contribute to the task according to their ability. Grain registration, an accounting of peasant grain stocks to find "surpluses," was a continuation of a reformist trend within the state bureaucracy to replace customary means of allotting state obligations with an effort to base them on an assessment of household productive capacity. Evidence from Penza Province suggests that grain registration, both data gathering and interpretation, played a complex role in the evolution of grain procurement policy. The implementation of registration was impacted by local conditions and was embraced when and where it served local interests. Registration contributed to significant tensions within the state apparatus; it exacerbated the growth of the localism that undermined the authority of the hierarchical procurement apparatus. Grain registration revealed the adaptability of peasants and local officials in the face of top-down reform and prompted efforts to enhance state effectiveness. Ultimately, the persistent challenges posed by grain registration forced the regime to abandon registration and to reorganize the provincial apparatus to enhance oversight of local officials. [ABSTRACT FROM AUTHOR]

The Middle Triassic Tredian Formation is well exposed in the western region of the Salt Range. It is mostly composed of sandstone with minor alternations of shales and dolomite. This is the first integrated attempt using petrographical and geochemical features to reveal palaeoclimate during deposition of the Tredian Formation. This work sheds light on the petrographical and geochemical properties of the Tredian sandstone in order to date various layers and evaluate the palaeoclimate. The formation was sampled at two distinct stratigraphic layers for petrographic and geochemical analysis of major and trace elements. The sandstone of the Tredian Formation is sub‐feldspathic to feldspathic arenite with sub‐angular to rounded grains that are moderately to extensively sorted. The relative proportions of the quartz, feldspars and lithoclasts in the examined sandstone samples shows that the Tredian sediments originated from the interior of the craton during a transitional continental regime. Chemical index of alteration values of 59, chemical index of weathering values of 67, and plagioclase index of alteration values of 74.5 indicate a low to moderate degree of weathering in the Tredian sediment source region. Based on the silica content, SiO2/Al2O3 ratios (2.7–6.1; mean 4.1), and chemical maturity index, it is deduced that the Tredian Formation was deposited in chemically immature to sub‐mature and dry to semi‐arid conditions. Geochemical proxies indicate the acidic source of sediment and deposition on the passive margin of the Indian Plate. The trace element characteristics of the sediments, especially the Rb/Sr, Cu/Zn, Ni/Co, V/Cr and Sr/Ba ratios, indicate that the sediments originated from the first weathering cycle and support the notion that they were deposited in an oxidising continental environment. A semi‐arid to arid palaeoclimate predominated through the Middle Triassic at the north‐western passive continental margin of the Indian Plate in the south‐eastern Neo‐Tethys. [ABSTRACT FROM AUTHOR]

Understanding the near-ground vertical and temporal photochemical O3 formation mechanism is important to mitigate the O3 pollution. Here, we measured the vertical profiles of O3 and its precursors at six different heights from 5-335 m using a newly built vertical observation system in Pearl River Delta (PRD) region, China. The net photochemical ozone production rate (P (O3)net) and O3 formation sensitivities at various heights were diagnosed using an observation-based model coupled with the Master Chemical Mechanism (MCM v3.3.1). Moreover, for the assessment of model performance and the causative factors behind O3 pollution episodes, the net photochemical ozone production rate (P (O3)net) was measured at 5 m ground level utilizing a custom-built detection system. In total three O3 pollution episodes and two non-episodes were captured. The identified O3 pollution episodes were found to be jointly influenced by both photochemical production and physical transport, with local photochemical reactions play a dominate role. The high index of agreement (IOA) calculated from comparing the modelled and measured P (O3)net values indicated the rationality to investigate the vertical and temporal variability of O3 formation mechanism using modelling results. However, the measured P (O3)net values were generally higher than the modelled P (O3)net values, particularly under high NOx conditions, which may indicate a potential underestimation of total RO2 by the model. Throughout the measurement period, the contribution of different reaction pathways to O3 production remained consistent across various heights, with HO2+NO as the major O3 production pathway, followed by RO2+NO. We saw P (O3)net decreased with the increase of the measurement height, primarily attributed to the decreased O3 precursors anthropogenic organic compounds (AVOC) and oxygenated volatile organic compounds (OVOC). O3 formation regimes were similar at different heights during both episodes and non-episodes, which was located either in volatile organic compounds (VOCs) sensitive regime or in transition regime and more sensitive to VOCs. Diurnally, photochemical O3 formation typically remained in the VOCs sensitive regime during the morning and noon time, but in the transitional regime and more sensitive to VOCs in the afternoon at around 16:00 LT. The vertical and temporal O3 formation are most sensitive to AVOC and OVOC, which suggests that targeting VOCs, especially AVOC and OVOC, for control measures is more practical and feasible at the observation site. The vertical temporal analysis of O3 formation mechanisms near the ground surface in this study provides critical foundational knowledge for formulating effective short-term emergency and long-term strategies to combat O3 pollution in the PRD region of China. [ABSTRACT FROM AUTHOR]

O3 poses a significant threat to human health and the ecological environment. In recent years, O3 pollution has become increasingly serious, making it difficult to accurately control O3 precursor emissions. Satellite indicator methods, such as the FNR (formaldehyde-to-nitrogen dioxide ratio (HCHO/NO2 ratio)), provide an effective way to identify ozone pollution control areas on a large geographical scale due to their simple acquisition of datasets. This can help determine the primary factors contributing to O3 pollution and assist in managing it. Based on TROPOMI data from May 2018 to December 2022, combined with ground-based monitoring data from the China National Environmental Monitoring Centre, we explored the uncertainty associated with using the HCHO/NO2 ratio (FNR) as an indicator in ozone control area determination. We focused on the four representative regions in China: Jing-Jin-Ji-Lu-Yu (JJJLY), Jiang-Zhe-Hu-Wan (JZHW), Chuan-Yu (CY), and South China. By using the statistical curve-fitting method, we found that the FNR thresholds were 3.5–5.1, 2.0–4.0, 2.5–4.2, and 1.7–3.5, respectively. Meanwhile, we analyzed the spatial and temporal characteristics of the HCHO, NO2, and O3 control areas. The HCHO concentrations and NO2 concentrations had obvious cyclical patterns, with higher HCHO column densities occurring in summer and higher NO2 concentrations in winter. These high values always appeared in areas with dense population activities and well-developed economies. The distribution characteristics of the ozone control areas indicated that during O3 pollution periods, the urban areas with industrial activities and high population densities were primarily controlled by VOCs, and the suburban areas gradually shifted from VOC-limited regimes to transitional regimes and eventually reverted back to VOC-limited regimes. In contrast, the rural and other remote areas with relatively less development were mainly controlled by NOx. The FNR also exhibited periodic variations, with higher values mostly appearing in summer and lower values appearing in winter. This study identifies the main factors contributing to O3 pollution in different regions of China and can serve as a valuable reference for O3 pollution control. [ABSTRACT FROM AUTHOR]

Qian Daosun (1887–1966) was imprisoned for collaborating with the Provisional Government in North China under Japanese occupation, and to this day he is labelled as hanjian (traitor). Yet, Qian was first and foremost a cultural literatus, librarian, and an exceptional translator with an in-depth understanding of Japanese culture and languages. This article examines the crucial role that Japan and the Japanese language played for Chinese cultural literati in their quest to save China. It also brings to the forefront the dilemmas and agonizing choices Qian faced in his attempt to promote Sino-Japanese cultural exchange in the midst of war, in particular as a librarian. Wartime libraries are highly contested sites of selection, destruction, censorship, preservation, confiscation, and knowledge production. An added layer of complexity was Japan's cultural policy in China that promoted Japanese-language collections and governed libraries such as the Beijing1 Modern Science Library where Qian worked. What exacerbated Qian's dilemmas was his upbringing, which led him to form close personal connections with like-minded Japanese literati. Lastly, this article revisits the hanjian label by comparing Qian's fate to that of other librarians and returned students of Japan, such as May Fourth writer Lu Xun and patriotic bibliophile Zheng Zhenduo. By deliberately examining May Fourth writers alongside hanjian and Japanese intermediaries, the intention is to dismount arbitrary labels and divisions that have set them apart and against each other in the resistance versus collaboration dichotomy. [ABSTRACT FROM AUTHOR]

In the summer of 1604, the Transylvanian Council of Government, which had been formed shortly before, submitted a longer report to King Rudolf I of Hungary. They reported on the administration and financial situation of the newly pacified province of Transylvania. The most pressing issue, however, was the pay and maintenance of the mercenary corps stationed in Transylvania. Accordingly, the bulk of the report is devoted to discussing problems relating to the army. The report gives us an idea of how a Council of Government (Regiment) that had already been 'tried and tested' in the Austrian hereditary provinces functioned in Transylvania, and introduces the challenges members of the Council had to face. [ABSTRACT FROM AUTHOR]

Copyright of Revista Anuario de Historia Regional y de las Fronteras is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Lua Nova is the property of CEDEC and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Under the influence of climate change, the increasing occurrence of extreme weather events, such as heatwaves, has led to an enhanced frequency of ozone (O3) pollution issues. In August 2022, the Sichuan Basin (SCB), a typical large-scale geographical terrain located in southwestern China, experienced the most severe heatwave over the last 20 years. The heatwave led to substantial disparities in O3 levels across the region. Here, by integrating observations, machine learnings and numerical simulations, we aim to understand the diverse O3 formation mechanisms in two mega cities, Chengdu (western location) and Chongqing (eastern location). Observational data showed that Chengdu experienced a consecutive 17-day period of O3 exceedance, in contrast to Chongqing, where O3 concentrations remained below the standard. Meteorological and precursor factors were assessed, spotlighting high temperatures, intense solar radiation, and overnight accumulative pollutants as key contributors to O3 concentrations. The interplay of isoprene, temperature, and O3, alongside the observation-based box model and MEGAN simulations, underscored the significant role of intensified biogenic VOCs (BVOCs) on O3 formations. Interestingly, Chongqing exhibited nearly double the BVOCs emissions of Chengdu, yet contributed less to O3 concentrations. This discrepancy was addressed through CMAQ-DDM simulations and satellite diagnosis by investigating the O3-NO x -VOCs sensitivity. Notably, Chengdu displayed a VOCs-driven sensitivity, while Chongqing showed a transitional regime. Moreover, the regional transport also played a pivotal role in the spatial divergence of O3 pollution. Cross-regional transport predominantly influenced Chongqing (contributing ~80%), whereas Chengdu was mainly affected by the emissions within the basin. The local accumulated pollutants gave rise to the atmospheric oxidizing capacity, resulting in a substantial photochemical contribution to O3 levels (49.9 ppbv/hour) in Chengdu. This comparison of the difference provides the insights into the complex interplay of meteorology, natural emissions, and anthropogenic sources during heatwaves, guiding the necessity of targeted pollution control measures in regional scales. [ABSTRACT FROM AUTHOR]

In recent years, the concentration of surface ozone (O3) has increased in China. The formation regime of ozone is closely related to the ratio of volatile organic compounds (VOCs) to nitrogen oxides (NOx). To explain this increase in ozone, we determined the sensitivity of ozone generation by determining the regional threshold of the ratio of formaldehyde to nitrogen dioxide (HCHO/NO2) in the satellite troposphere. The different FNR(HCHO/NO2) ratio ranges indicate three formation regimes: VOC limited, transitional, and NOx limited. Polynomial fitting models were used to determine the threshold range for the transitional regime in the BTH region (2.0, 3.1). The ozone formation regime in the BTH (Beijing–Tianjin–Hebei) region mainly exhibited a transitional and NOx-limited regime. VOC-limited regimes are mainly distributed in urban agglomeration areas, transitional regimes are mainly concentrated in urban expansion areas, and non-urban areas are mainly controlled by NOx. The concentrations of HCHO and NO2 in the BTH region showed a trend of urban agglomeration areas > urban expansion areas > non-urban areas in different land types from 2019 to 2022, whereas the FNR showed an opposite trend. [ABSTRACT FROM AUTHOR]

The purpose is to attempt to analyze the socio-political development and military situation in the Volyn area during the Ukrainian Revolution of 1917--1921. The research methodology is based on the use of general scientific and specifically historical research methods, including problemchronological, synchronous, diachronic, comparative-historical, etc. The scientific novelty. An attempt is made to summarize the events of the Ukrainian revolution on the territory of Volyn in the context of the national and international situation. Conclusions. During 1917--1921, Volyn, like all of Ukraine, experienced revolutionary upheavals. During the time of administration by the Russian Provisional Government, the people of Volyn felt the rise of national consciousness in the general revolutionary wave, formed the structures of the national movement, and undertook the democratization and Ukrainization of social and political life. In November 1917, Volyn, as a part of the Ukrainian People's Republic, almost immediately fell into the vortex of the first Bolshevik-Ukrainian war. Also, the front of World War I ran through the region, which certainly left its mark. The outermost west of Volyn continued to be under the control of the Austrians until November 1918. In 1919, it became one of the epicenters of the Ukrainian Revolution, where significant events took place (including V. Oskilko's coup d'état attempt, O. Volokh's theft of the state treasury, the Liubar Declaration, etc.). Shortly, Volyn became the place of the last chord of the Ukrainian revolution -- the 2nd Winter Campaign of the Ukrainian People's Republic Army. [ABSTRACT FROM AUTHOR]

We study two coupled active rotators with Kuramoto-type coupling and focus our attention to specific transitional regimes where the coupling is neither attractive nor repulsive. We show that certain such situations at the edge of synchronization can be characterized by the existence of a time-reversal symmetry of the system. We identify two different cases with such a time-reversal symmetry. The first case is characterized by a non-reciprocal attractive/repulsive coupling. The second case is a reciprocal coupling exactly at the edge between attraction and repulsion. We give a detailed description of possible different types of dynamics and bifurcations for both cases. In particular, we show how the time-reversible coupling can induce both oscillation death and oscillation birth to the active rotators. Moreover, we analyse the coexistence of conservative and dissipative regions in phase space, which is a typical feature of systems with a time-reversal symmetry. We show also, how perturbations breaking the time-reversal symmetry and destroying the conservative regions can lead to complicated types of dissipative dynamics such as the emergence of long-period cycles showing a bursting-like behaviour. [ABSTRACT FROM AUTHOR]

Urban air pollution continues to pose a significant health threat, despite regulations to control emissions. Here we present a comparative analysis of urban ozone (O3) responses to nitrogen oxide (NOx) changes in China and the United States (US) over 2015–2020 by integrating various data‐ and model‐based methods. The data‐based deep learning (DL) model exhibited good performance in simulating urban air quality: the correlation coefficients (R) of O3 daily variabilities with respect to independent O3 observations are 0.88 and 0.79 over N. China, 0.87 and 0.90 over S. China, and 0.87 and 0.49 over E. United States by the DL and GEOS‐Chem chemical transport models, respectively. Furthermore, the data‐based methods suggest volatile organic compound (VOC)‐limited regimes in urban areas over northern inland China and transitional regimes over eastern US urban areas; in contrast, GEOS‐Chem model suggests strong NOx‐limited regimes. Sensitivity analysis indicates that the inconsistent O3 responses are partially caused by the inaccurate representation of O3 precursor concentrations at the locations of urban air quality stations in the simulations, while the data‐based methods are driven by the variabilities in local O3 precursor concentrations and meteorological conditions. The O3 responses to NOx changes reported here provide a better understanding of urban O3 pollution; for example, reductions in NOx emissions are suggested to have resulted in an increase in surface O3 by approximately 7 ppb in the Sichuan Basin in 2014–2020. Plain Language Summary: Ozone (O3) at the surface level is an important pollutant with complicated photochemistry. Here we analyze the responses of urban O3 concentrations to nitrogen oxide (NOx) changes in China and the United States (US) over 2015–2020. The data‐based methods suggest that NOx emission declines have resulted in increases in urban O3 concentrations over northern inland China, while urban O3 concentrations over eastern US are less sensitive to NOx changes. In contrast, GEOS‐Chem simulation suggests that NOx emission declines can result in dramatic decreases in urban O3 concentrations over both China and the US. The derived O3 responses in this work are helpful for making effective regulatory policies to control urban O3 pollution. Key Points: Data‐based methods suggest VOC‐limited regimes over northern inland China and transitional regimes over eastern United States urban areasGEOS‐Chem simulation suggests strong NOx‐limited regimesData‐based methods have the potential to provide new insights for air quality regulations as a supplement to Chemical transport models [ABSTRACT FROM AUTHOR]

Advancements in space exploration and sample return technology present a unique opportunity to leverage sample return capsules (SRCs) towards studying atmospheric entry of meteoroids and asteroids. Specifically engineered for the secure transport of valuable extraterrestrial samples from interplanetary space to Earth, SRCs offer unexpected benefits that reach beyond their intended purpose. As SRCs enter the Earth's atmosphere at hypervelocity, they are analogous to naturally occurring meteoroids and thus, for all intents and purposes, can be considered artificial meteors. Furthermore, SRCs are capable of generating shockwaves upon reaching the lower transitional flow regime, and thus can be detected by strategically positioned geophysical instrumentation. NASA's OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) SRC is one of only a handful of artificial objects to re-enter the Earth's atmosphere from interplanetary space since the end of the Apollo era and it will provide an unprecedented observational opportunity. This review summarizes past infrasound and seismic observational studies of SRC re-entries since the end of the Apollo era and presents their utility towards the better characterization of meteoroid flight through the atmosphere. [ABSTRACT FROM AUTHOR]

Law 13/2013 was published in the Official State Gazette on 25 May and expressly clarified that concessions existing as at the entry into force of Law 27/1992 can benefit from the extensions set out in article 82.2, as currently in force, of the Consolidated Text of the Law on State Ports and the Merchant Marine. This article analyses and summarises the background and scope of this clarification. [ABSTRACT FROM AUTHOR]

The destruction of marine soft clays' macropore structure results in large-strain deformation during consolidation, as well as the potential to alter rheological deformation characteristics. A sectionalised regimes rheological model was adopted to describe the structural characteristics under the isotache framework, which led to a nonlinear variation of geometrical boundaries and material properties during consolidation. A semi-analytical theory combining numerical and analytical methods was developed, and the solutions for excess pore water pressure, degree of consolidation, and settlement were derived and computationally programmed. Using parametric analysis, the effects of rheological and structural characteristics on the consolidation behaviour of soft clay were discussed compared to the solutions of other theories. The coefficient of secondary consolidation in the transitional regime has an impact beginning in the middle of primary consolidation. The proposed solutions for degree of consolidation are smaller than the small-strain solutions during the early period of primary consolidation but change larger as consolidation progresses. [ABSTRACT FROM AUTHOR]

The proliferation of autonomous systems like unmanned aerial vehicles, autonomous vehicles and AI-powered industrial and social robots can benefit society significantly, but these systems also present significant governance challenges in operational, legal, economic, social, and ethical dimensions. Singapore's role as a front-runner in the trial of autonomous systems presents an insightful case to study whether the current provisional regulations address the challenges. With multiple stakeholder involvement in setting provisional regulations, government stewardship is essential for coordinating robust regulation and helping to address complex issues such as ethical dilemmas and social connectedness in governing autonomous systems. [ABSTRACT FROM AUTHOR]

The standard vessel for mixing in the process industry is a baffled tank. This design is very common especially for low viscosity fluids. Nonetheless, unbaffled vessels are found in industry and the laboratory. The reasons given for using unbaffled vessels are primarily concerns around cleaning the vessel between batches and the possibility of stagnation zones in high viscosity fluids particularly when properties change over the processing time. In this paper we will examine the effect of baffles on the blend time using one vessel: with and without baffles. The blend time was measured using the iodine color change method using a range of viscosities and Reynolds Numbers. The depth of the vortex was also measured. The same axial flow-down pumping impeller is used. In this work we observed that the flow patterns are dramatically different between unbaffled and baffled tanks. At high Reynolds Numbers with the baffled configuration, we see the familiar turbulent diffusion throughout the vessel. Without the baffles the fluid segregates into two zones: a swirling inner zone near the shaft and a more turbulent outer zone. The overall blend time is longer in the baffled tank at the same rotational speed compared to the baffled tank. This difference decreases with increasing Reynolds Number. We identified two blend times in using unbaffled tanks, a short blend time for the outer zone and a much longer time for the inner vortex centered zone which defines the overall blend time for the vessel. At low Reynolds Numbers the baffled blending is in the transitional flow regime between turbulent and laminar with a combination of eddies and striations. The last region of the tank to become completely mixed is located behind the baffles. Unbaffled blend times are shorter and as the Reynolds Number decreases the difference increases. The vortex is also reduced with decreasing Reynolds number. We consider this work just a beginning step in a long study and hope this work will be picked up by other researchers as happened so many times with Professor Nienow's work. [Display omitted] • The effect of Reynolds Number on the dimensionless blend time for both baffled and unbaffled agitated vessels is shown in this paper. • The data shows that baffles decrease the blend time in turbulent flow and increase the blend time in transitional flow. [ABSTRACT FROM AUTHOR]