杨世明1,刘克瑾2,姚辉江2,黄硕硕2,杜春来1,章敬波1 YANG Shiming1, LIU Kejin2, YAO Huijiang2, HUANG Shuoshuo2, DU Chunlai1, ZHANG Jingbo1
旨在为筒仓的设计和优化提供参考，基于自主设计的半圆柱形有机玻璃平底筒仓模型，进行了平均粒径分别为15、3.5 mm和5.5 mm陶球颗粒的室内筒仓中心卸料试验和离散元数值模拟。采用流态观察、速度分析、颗粒位移追踪3种方法探究了3组粒径颗粒的流态演变过程，分析了仓壁压力分布及变化规律，通过PFC 2D得到孔隙率、力链等细观变量分布并联合宏观层次的物理试验探讨了粒径大小对流态及仓壁压力的影响。结果表明：粒径对颗粒流态的整体演化过程无显著影响，不同粒径颗粒的流态均由整体流经漏斗流过渡为管状流；大粒径颗粒完成卸料过程耗时更久，卸料速率更慢；粒径对颗粒的流动轨迹无显著影响；边界区并不是一成不变的，在卸料过程中随着粒径的增大而逐渐上移；不同粒径颗粒组的峰值卸料压力最大值均位于距离仓底约1/3的位置；粒径越大，仓壁的压力波动越剧烈，峰值卸料压力也越大。综上，粒径对平底筒仓中心卸料的流态无显著影响，不同粒径的颗粒流态演化过程和颗粒流动轨迹具有相似性，粒径越大产生的仓壁卸料压力也越大。在实际工程中，需考虑粒径对筒仓结构安全性的影响。
To provide a reference for the design and optimization of silos, based on a self-designed semi-cylindrical plexiglass flat-bottom silo model, indoor silo center discharge tests and discrete element numerical simulations were conducted using ceramic ball particles with average particle size of 15, 3.5 mm and 5.5 mm. Three methods of flow pattern observation, velocity analysis, and particle displacement tracking were used to explore the flow pattern evolution of the three groups of particles with different particle sizes. The pressure distribution and variation of the silo wall were analyzed, and the distribution of microscopic variables such as porosity and force chain obtained from PFC 2D, along with macroscopic physical tests, were used to investigate the effect of particle size on flow pattern and silo wall pressure. The results showed that particle size had no significant effect on the overall evolution of particle flow pattern, and the flow pattern of particles with different particle size shifted from mass flow through funnel flow to tubular flow. Larger particle sizes of particles resulted in a longer discharge process with slower discharge rates. Particle size had no significant effect on the particle flow trajectories. The boundary zone was not fixed and gradually moved upwards with the increase of particle size during the discharge process. The peak of discharge pressure for different particle size groups was located approximately one-third of the way from the silo bottom. The larger the particle size, the more severe the pressure fluctuations on the silo wall, and the higher the peak of discharge pressure. In summary, particle size has no significant effect on the flow pattern of the silo center discharge. The flow pattern evolution and particle flow trajectories of particles with different particle sizes are similar. Larger particles generate higher discharge pressure on the silo wall. In practical engineering, the impact of particle size on silo structure safety should be considered.
Abstract
This article investigates the epistemological convergence between French historiography and French Discourse Analysis (FDA), emphasizing their shared focus on language as a vehicle for historical meaning and ideological formation. Tracing the evolution from the Annales School to post-structuralist thinkers such as Foucault and LaCapra, the study highlights how history has increasingly embraced discourse as both a methodological tool and an object of analysis. Through a case study of Santiago Abascal, leader of Spain’s far-right party Vox, the article illustrates how FDA concepts – such as lexical worlds, interdiscursivity, and discursive ethos – can be applied to political rhetoric in the digital age. Using lexicometric methods (IraMuTeQ, SketchEngine) and qualitative interpretation, the study analyzes a corpus of Abascal’s tweets (2019-2022), focusing particularly on the term golpista as a strategic signifier of ideological antagonism. The findings show how far-right discourse reactivates historically loaded terms to construct binary oppositions and mobilize collective memory. Ultimately, the article argues that FDA offers historians a powerful framework to interrogate the linguistic production of identity, power, and historical continuity in contemporary political narratives.
Anthropology, Language. Linguistic theory. Comparative grammar
Juliane Mailly, Louise Riotte-Lambert, Mathieu Lihoreau
Accurate prediction of pollination processes is a key challenge for sustainable food production and the conservation of natural ecosystems. For many plants, pollen dispersal is mediated by the foraging movements of nectarivore animals. While most current models of pollination ecology assume random pollen movements, studies in animal behaviour show how pollinating insects, birds and bats rely on sensory cues, learning and memory to visit flowers, thereby producing complex movement patterns. Building upon a brief review of pollination and movement models, we argue that we need to better consider pollinators’ cognition to improve predictions of animal-mediated pollination across all spatial scales, from individual flowers, to plants, habitat patches and landscapes. We propose a practical roadmap for the integration of behavioural models into pollination models and discuss how this synthesis can refine predictions regarding plant mating patterns and fitness. Such crosstalk between animal behaviour and plant ecology research will provide powerful mechanistic tools to predict and act on pollination services in the context of a looming crisis.
Robert Mzungu Runya, Chris McGonigle, Rory Quinn
et al.
ABSTRACT Understanding the spatial dynamics of harbour porpoise (Phocoena phocoena) is crucial for effective conservation and management. The study presents a multidisciplinary approach to modelling and analysing the site occurrence and habitat use of Phocoena phocoena within the Skerries and Causeway Special Area of Conservation (SAC), identifying areas where they were seen surfacing and/or spending the most time. Using data derived from multibeam echosounders (MBES), particle size analysis of sediments, hydrodynamic modelling, and theodolite tracking observations, the study examines the influence of local hydrodynamics and environmental conditions on the spatial distribution of harbour porpoises. Kernel density analysis of 451 porpoise sightings over an 11‐day survey demonstrated that dense clusters and higher aggregations occurred within ~500 m of the shoreline. Generalised Additive Models (GAMs) identified slope, aspect, backscatter intensity and sediment grain size as the most significant environmental predictors, accounting for 47.6% of the deviance in harbour porpoise distribution. Porpoises' occurrence was particularly spatially coincident with coarser sediments (4.25–5 mm), and their distribution was highly concentrated around headlands, shoreline and within a 3‐h window before and after high water. Overall, these findings highlight the dynamic nature of harbour porpoises' use of habitat in space and time, with models predicting a high probability of porpoise encounters (> 0.6) nearshore, particularly in headland areas characterised by local flow acceleration and coarser seabeds. The study presents a robust workflow for developing a porpoise‐specific monitoring program. By leveraging multidisciplinary methodological approaches, the study provides a scientific basis for refining marine conservation measures, delivering long‐term protection for harbour porpoise habitats under existing legal and management frameworks both within and beyond the SAC boundaries.
Tunneling in fractured zones significantly affects surface and building deformation. This paper investigates the deformation of overlying buildings and the surrounding ground induced by multi-line TBM tunneling in fractured zones of the Qingdao Metro, combining a 3D physical model test, numerical simulations, and field monitoring to analyze the evolution of settlement and structural responses. The results show that settlement induced by TBM excavation peaks at the center and diminishes laterally, with amplified differential settlement and building torsion near fractured zones. Comparative analyses of reinforcement strategies indicate that crown grouting is the most effective in reducing deformation. Sensitivity analysis further indicates that tunnel depth, grouting pressure, and building–tunnel relative position are the dominant factors influencing building settlement. The findings provide practical guidance for similar projects in complex geological conditions and contribute to deformation control in underground works.
Marcos G. Alberti, Alejandro Enfedaque, Duarte M. V. Faria
et al.
Material optimization was one of the challenges for achieving cost-competitive solutions when concrete was introduced in construction, leading to new structural shapes for both civil works and buildings. As concrete construction became dominant, saving material was given less significance, and the selection of the structural typology was mostly influenced by construction or architectural considerations. Simple and non-time-consuming methods for building thus arose as the dominant criteria for design, and this led to the construction of less efficient structures. Currently, the awareness of the environmental footprint in concrete construction has brought the focus again to the topic of structural efficiency and material optimization. In addition, knowledge of material technology is pushing the use of cements and binders with lower environmental impact. Within this framework, Fiber-Reinforced Concrete (FRC) has been identified as a promising evolution of ordinary concrete construction. In this paper, a discussion is presented on the structural properties required for efficient design, focusing on the toughness and deformation capacity of the material. By means of several examples, the benefits and potential application of limit analysis to design at the Ultimate Limit State with FRC are shown. On this basis, the environmental impact of a tailored mix design and structural typology is investigated for the case of slabs in buildings, showing the significant impact that might be expected (potentially reducing CO<sub>2</sub>-eq emissions to half or even less in slabs when compared to ordinary solutions).
Mitsuru Tanaka, Yuya Hirose, Yoshiyuki Harada
et al.
Sulfide kesterite Cu2ZnSnS4 (CZTS), an intrinsic p-type semiconductor, provides an attractive low-cost, environmentally friendly photoelectrochemical (PEC) water splitting to evolve hydrogen. The purpose of this study was to clarify the effect of the chemical composition of CZTS on the PEC properties and the correlation with their structures. The CZTS was fabricated on a Mo/glass by a non-vacuum process, i.e., co-electrodeposition (co-ED) of Cu-Zn-Sn (CZT) alloys, followed by sulfurization with solid sulfur. To optimize the chemical composition of CZTS, the bath concentrations, applied potentials and amounts of electric charge for preparation conditions of the CZT precursors were examined. The CZTS with Cu-poor and Sn-rich composition compared with stoichiometry was found to exhibit relatively effective PEC water splitting. It was suggested that the high PEC performance was attributed to efficient charge carrier transport due to the presence of a small amount of SnO2 phase on the CZTS surface.
Among mobile terrestrial animals, movement among microsites can allow individuals to behaviorally moderate their body temperatures and rates of water loss, which can have important consequences for activity times, growth, fecundity, and survival. Ground-layer vegetation can change the availability and variability of microclimates; however, gaps in our understanding of how individuals interact with the microclimates created by vegetation limit our ability to inform management actions for wildlife. Amphibians can simultaneously balance operant body temperatures and water loss and the availability of heterogeneous microclimates should moderate how effectively they are able to do so. However, relatively few studies have attempted to mechanistically demonstrate how ground vegetation-driven effects on microclimatic variation may affect amphibian performance and survival. Agent-based modeling (ABM) can incorporate behavior and other mechanisms to understand how animals interact with their environments to result in larger scale patterns. They are effective for exploring alternative scenarios and representing the uncertainty in systems. Here, we use ABMs to integrate field and laboratory measurements of movement behavior, physiology, and plant effects on near-ground microclimate to explore how ground vegetation and the availability of terrestrial refugia may affect the survival and terrestrial distributions of juvenile gopher frogs (Rana capito) under two weather regimes. We also examine how assumptions regarding micro-scale movement (< 1 m2) affect the influence of ground vegetation on survival and settlement within refugia. While all variables affected settlement and survival, our models predict that inter-annual variation in weather and the density and spatial distribution of permanent refugia likely have the greatest influence on juvenile survival. The benefit of increased ground vegetation was dependent on the reasonable assumption that gopher frogs exhibit microclimate habitat selection throughout the day and night to limit water loss. Our models suggest that vegetation would be most beneficial to amphibians under warmer weather regimes provided there is sufficient rainfall.
Improved knowledge on the regulation of reproductive diapause in Coccinella septempunctata, an important predator of aphids, is crucial for improving shelf-life and mass production of the ladybeetles. In many insects, the absence of juvenile hormone (JH) is a central regulator of reproductive diapause. JH is principally degraded by JH esterase (JHE) and JH epoxide hydrolase (JHEH). Previous studies have shown that genes encoding these enzymes were upregulated in early diapause of C. septempunctata, but whether increased JH degradation contributes to the reduction of JH levels and facilitates reproductive diapause remains unknown. Here, we investigate the role of JH and JH degradation genes during reproductive diapause in C. septempunctata females. Applying methoprene, a JH analogue, to the diapause preparation females clearly elevated JH signaling and reversed diapause program, suggesting that a lower level of JH is critical for the induction of reproductive diapause in the ladybeetle. Full-length cDNA sequences of JHE and JHEH were cloned and characterized, and their deduced proteins contain all the conserved active domains and typical motifs as identified in other insects. The expressions of JHE and JHEH were both significantly increased in diapause preparation and remained at a high level for a period throughout diapause, and then decreased after the termination of diapause. Knocking down these JH degradation genes clearly increased the expression levels of JH-inducible genes Krüppel-homolog 1 (Kr-h1) and vitellogenin (Vg), indicating an elevated JH level. Simultaneously, silencing JH degradation genes distinctly reduced diapause-related features and promotes reproduction, indicated by accelerated ovary growth, yolk deposition, and suppressed lipid accumulation. These results indicate that the enhanced JH degradation plays a critical role in regulating reproductive diapause of C. septempunctata.
Giovanni Boccia Artieri, Francesca Greco, Gevisa La Rocca
<span class="abs_content">The article focuses on Italians' reactions to the pandemic on Twitter. During the first phase of the 2020 lockdown (from the beginning of March 2020 - to the beginning of May 2020), a real-time dataset was built, linking data scratching to three events related to the introduction of the Prime Minister's decrees and his press conferences. The chosen observation point is Twitter, platform that allows us to monitor the emergence of discussions on public issues, extremely synchronized with events and news – which is, moreover, a feature of use of this platform. The coronavirus hashtag was chosen as a mechanism to track the development of Italian reactions, following the evolution of its sense and sensemaking and considering it as a polysemic collector. The aim is to identify within the tweets the actors, the topics, and the tone of the debate in an open public space. Furthermore, the analysis is carried out in search of the Italians' perception of the lockdown and whether they are in favor of it because of the defense of public health or they see it as a restriction of their individual freedom. The analysis, which used the socio-constructivist approach of Emotional Text Mining, reveals two explanatory-dimensions in the governance of the crisis: lockdown and breakdown and allows us to understand the reasons for Twitter's instinct-reactions.</span><br />
The aim of this work is the study of the fatigue behaviour of API X60 steel and the influence of thermal and mechanical treatments. The evaluation of the integrity and safety of welded structures dictates the approach taken in this research. The microstructural observations on the different zones of the weld seam indicates that the variation of heterogeneous structure is a progressive destruction of the strips of lamination which cause a new phase leading to a drop in the mechanical properties requiring treatment after welding. The fatigue cracking rate diverges beyond the threshold of ??, but no deviation of the crack from its propagation axis was noticed, which confirms the correct choice of filler metal over that of the base metal with an overmatching M = 1.1, and the treatments applied to the structure. This fatigue cracking rate transversal to the welding direction initially presents an aspect similar to that of BM but registers a delay as soon as the crack tip enters the second zone (HAZ) then it progresses rapidly. This evolution is characterized by a disturbance due to the repeated change of microstructure.
Mechanical engineering and machinery, Structural engineering (General)
W. H. Lipscomb, G. R. Leguy, N. C. Jourdain
et al.
<p>The future retreat rate for marine-based regions of the Antarctic Ice Sheet is one of the largest uncertainties in sea-level projections. The Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6) aims to improve projections and quantify uncertainties by running an ensemble of ice sheet models with
atmosphere and ocean forcing derived from global climate models.
Here, the Community Ice Sheet Model (CISM) is used to run ISMIP6-based projections of ocean-forced Antarctic Ice Sheet evolution. Using multiple combinations of sub-ice-shelf melt parameterizations and calibrations, CISM is spun up to steady state over many millennia. During the spin-up, basal friction parameters and basin-scale thermal forcing corrections are adjusted to optimize agreement with the observed ice thickness.
The model is then run forward for 550 years, from 1950–2500, applying ocean thermal forcing anomalies from six climate models. In all simulations, the ocean forcing triggers long-term retreat of the West Antarctic Ice Sheet, especially in the Filchner–Ronne and Ross sectors. Mass loss accelerates late in the 21st century and then rises steadily for several centuries without leveling off.
The resulting ocean-forced sea-level rise at year 2500 varies from about 150 to 1300 mm, depending on the melt scheme and ocean forcing.
Further experiments show relatively high sensitivity to the basal friction law, moderate sensitivity to grid resolution and the prescribed collapse of small ice shelves, and low sensitivity to the stress-balance approximation.
The Amundsen sector exhibits threshold behavior, with modest retreat under many parameter settings but complete collapse under some combinations of low basal friction and high thermal forcing anomalies.
Large uncertainties remain, as a result of parameterized sub-shelf melt rates,
simplified treatments of calving and basal friction, and the lack of ice–ocean coupling.</p>
Abstract Insufficient energy reserves are widely considered to be a primary factor contributing to high rates of early benthic phase mortality among benthic marine invertebrates, but this hypothesis has been based mostly on indirect, observational evidence, and remains largely untested. We therefore examined the role of initial energy reserves in regulating survivorship and growth during the early benthic phase. Recently settled or hatched individuals of six invertebrate species were collected from natural populations, maintained without food, and their survivorship was monitored. Contrary to expectations, starved individuals of all six species had high survivorship through the critical first 10 days of the early benthic phase, with half of the species experiencing <2% mortality, and the remaining three species experiencing only 6%–12% mortality. For five of the six species, 50% mortality was reached only after ≥50 days of starvation. Additionally, no difference in short‐term survivorship was detected among starved individuals of three different size classes (a proxy for energy reserves) of N. ostrina hatchlings. Finally, the effect of different durations of delayed feeding (0–50 days) on recovery (i.e., growth and survivorship) once food was made available revealed that duration of starvation prior to feeding can nevertheless have significant longer‐term impacts on the proportion of individuals that survive or their ability to grow. Together, these findings suggest that depleted energy reserves are not a primary cause of high mortality at the start of the early benthic phase, as had previously been hypothesized. Levels of energy reserves did influence growth, however, suggesting a possible indirect influence on performance by leaving individuals vulnerable for longer periods.
The article examines the complex and fluctuant relationship which exists between the Moroccan regime and salafists from the 1970s until the ‘Arab Spring’. In each moment of this evolution, the regime opts for a pragmatic approach which consists in using this religious trend to meet pressing demands and priorities of a political and security nature. Ten years after breaking up with salafist groups, both quietists and jihadists, suspected to be responsible for the 2003 Casablanca attacks, the regime seeks henceforth to reconcile with salafis with the purpose to integrate them, or at least neutralise them, in the ongoing politico-religious reconfiguration process. Yet, this reconciliation, which aims to defuse the socio-political tensions and uncertainty the country has experienced in the aftermath of 2011 in addition to counterbalance the Islamists rising to power, is likely to challenge or even contradict certain ideological and doctrinal choices that have hitherto framed the religious policy since 2003.
Intracerebral hemorrhage (ICH) remains a prevalent and severe cause of death and disability worldwide. Control of the hypertensive response in acute ICH has been a mainstay of ICH management, yet the optimal approaches and the yield of recommended strategies have been difficult to establish despite a large body of literature. Over the years, theoretical and observed risks and benefits of intensive blood pressure reduction in ICH have been studied in the form of animal models, radiographic studies, and two recent large, randomized patient trials. In this article, we review the historical and developing data and discuss remaining questions surrounding blood pressure management in acute ICH.
A series of repeated load triaxial tests were conducted in this study to investigate the influences of compaction density and postcompaction moisture variation on the dynamic elastic modulus (Ed) and plastic permanent strain (PPS) of compacted lateritic soil. Specimens were compacted at optimum moisture content (OMC) and three degrees of compaction (90%, 93%, and 96%). Then the specimens were dried or wetted to different moisture contents (OMC, OMC±3%, OMC±6%, and OMC+9%) prior to testing for Ed and PPS. Results show that moisture content has greater influence on the Ed and PSS than compaction degree, and the increase in moisture content leads to a decrease of Ed and an increase of PPS. Furthermore, an empirical relationship between Ed and applied cyclic stress (σd) is developed that incorporates density and moisture variations. Three different evolution types of PPS with number of load cycles, plastic stable, plastic creep, and incremental collapse, are identified as the increase of moisture content. In addition, the critical dynamic stress (σdc) separating stable and unstable deformation is determined based on the shakedown concept. The envelope curves of σdc-moisture of lateritic soil with different degrees of compaction are also determined to provide reference for the pavement design.
Materials of engineering and construction. Mechanics of materials
Waleska M. Eloi, Sergio N. Duarte, Tales M. Soares
et al.
Objetivou-se, com este trabalho, avaliar o efeito de diferentes níveis de salinidade no solo provocados pelo uso da fertirrigação, nas características sensoriais de frutos do tomateiro. O experimento foi conduzido em duas etapas, a primeira desenvolvida em laboratório e a segunda realizada em estufa plástica. A primeira etapa consistiu de testes preliminares que possibilitaram a construção de curvas artificiais de salinização, visando à realização do processo de salinização artificial do solo; na segunda etapa estudou-se a evolução dos diferentes níveis iniciais de salinidade do solo, implementados por meio da aplicação de fertilizantes, de acordo com a marcha de absorção de nutrientes pela cultura. Os níveis iniciais de salinidade utilizados foram: 1,5; 2,5; 3,5; 4,5; 5,5 e 6,5 dS m-1. Para a análise sensorial dos frutos realizou-se o teste hedônico com 39 provadores. Verificou-se que os índices de salinidade utilizados não interferiram na aceitação do produto.<br>With the objective of evaluating the effect of different salinity levels in the soil provoked by the use of fertigation, on the sensory characteristics of tomato fruits, an experiment was conducted in two stages, being the first developed in laboratory and the second one accomplished in plastic greenhouse. The first stage consisted of preliminary tests that made possible the construction of artificial curves of salinization, seeking accomplishment of the process of artificial salinization of the soil. In the second stage the evolution of the different initial levels of soil salinity was studied, implemented through the application of fertilizers in agreement with the absorption of nutrients for the crop. The levels of salinity used were: 1.5, 2.5, 3.5, 4.5, 5.5 and 6.5 dS m-1. For the fruit sensory analysis the hedonic test with 39 individuals was performed. It was found that the levels of salinity used did not interfer in the acceptance of the product.