Search Results (20,650)

A collinear holographic data storage system stores two-dimensional information in the three-dimensional spatial domain of the medium, offering features such as high speed, high density, and long lifespan, making it a promising technology for the future of data storage. However, a collinear holographic data storage system is limited by the alignment error of the optical system and is also sensitive to environmental noise and external interference, which increases the reading error. When recording and reading holographic storage materials, synchronous marks are used for positioning to correct data misalignment. Therefore, optimizing synchronous mark design of data pages is crucial for improving storage stability and reading accuracy. In this paper, we propose a star-shaped synchronous mark to replace the square-shaped synchronous mark, which improves the holographic grating coupling efficiency. Experimental results show that this method enhances reconstruction strength and reduces reading errors caused by external factors. The star-shaped synchronous mark achieves a better spectral match with the reference pattern, yielding a stronger diffracted signal. Experimental results show that this method reduces the bit error rate by approximately 25% compared to square-shaped synchronous marks under displacement multiplexing. Full article

Addressing the problem of limited methane (CH₄) recovery degree under different production conditions in a target low-permeability carbonate gas reservoir, this study intends to further investigate the effect of carbon dioxide (CO₂) injection on enhanced gas recovery (EGR). A group of long-core physical simulation experiments of CO₂ injection for EGR was adopted. Field injection–production parameters were converted to laboratory conditions through similarity criteria to simulate the actual production process of gas wells. Systematic experiments on CH₄ depletion and CO₂ displacement were carried out under different irreducible water saturation, gas injection timing pressure and injection rates. The influence laws of each key parameter on the CO₂ breakthrough time and CH₄ recovery degree were analyzed emphatically, and the optimal injection–production scheme was obtained. For the target low-permeability carbonate gas reservoir (permeability < 1 mD), the optimal CO₂ injection scheme is as follows: for layers with medium to high irreducible water saturation (≥40%), CO₂ injection at a rate of 36,000 m³/d per well after the end of stable production (formation pressure > 7.38 MPa) can increase the CH₄ recovery degree by 3–5%. This study provides experimental support for the optimization of CO₂ injection schemes for enhanced recovery in gas reservoirs and the adjustment of gas reservoir development strategies under different irreducible water saturation conditions. Full article

An integrated numerical method is proposed for analyzing the nonlinear seismic response of near-fault building clusters, comprising three algorithms: (1) a structural investigated lump algorithm for elastoplastic dynamic response of structure; (2) a connecting investigated lump algorithm for bidirectional wave propagation between the site and elastoplastic building clusters; (3) a geomedia investigated lump algorithm for seismic wave propagation with an improved viscoelastic constitutive model, which allows independent definition of P/S-wave quality factors to characterize geomedia attenuation. Validated for its capability in simulating site-city dynamic interaction problems via a shaking table test, the method is applied to study the seismic response of near-fault building clusters in Xichang City under a hypothetical M_w6.8 earthquake. It is shown that irrespective of whether shallow geological structures are considered, clusters (c2–c4) situated in rupture-forward surface area within ~1.5 km of the fault trace entered the elastoplastic stage, while others (c1, c5) remained elastic. Shallow geological structures may reverse locally hanging-wall/footwall effects of both near-fault structural seismic response and ground motion. A notable seismic-response characteristic of near-fault structures undergoing the elastoplastic stage is that the permanent structural motion displacement (PSMD) at the slab of a specific floor incorporates not only the non-zero permanent ground motion displacement (PGMD) but also the non-zero final structural residual displacement (FSRD) relative to the supporting ground. The developed method could provide support for seismic damage assessment, site selection, and structural optimization design of near-fault building clusters. Full article

The Ordos Basin hosts abundant lacustrine shale oil resources. Adequately retained hydrocarbons in source rocks, together with favorable mobility, are prerequisites for large-scale shale oil exploitation. Therefore, the quantitative characterization of retained hydrocarbon content and mobility is a core research focus in shale oil exploration and development. This study investigates Chang 7 shale with varying lithofacies and geochemical characteristics. Stepwise pyrolysis and pyrolysis gas chromatography–mass spectrometry (GC–MS) were applied to analyze retained hydrocarbons in different occurrence states, their compositions, and biomarkers. In addition, nuclear magnetic resonance (NMR) combined with CO₂ flooding experiments was conducted, and the collected products under different displacement pressures were analyzed using GC–MS. The aim was to quantitatively examine the variations in expelled oil volume, compositional differences during migration, and occurrence features of shale oil within reservoir micro-pores. The results show the following: (1) Organic-rich shale is characterized by higher proportions of light and medium hydrocarbons, lower heavy fractions, and elevated aromatic hydrocarbon content. In contrast, low-organic-carbon mudstone or siltstone contains more medium and heavy hydrocarbons, with lower light and aromatic fractions. The C13−/C14+ ratio increases with total organic carbon (TOC). (2) In black shale, oil displacement is mainly contributed by mesopores. At low pressures, oil expulsion is difficult and dominated by heavy hydrocarbons. When pressure reaches a threshold, the capillary-bound oil in micropores is released, increasing production and improving oil quality. Muddy siltstone shows higher displacement efficiency than black shale, with contributions from pores of all sizes. At low pressures, its expelled oil volume is larger and lighter than that of black shale. With increasing pressure, the oil yield rises significantly, and medium–large pores produce heavier fractions compared with micropores, likely because light hydrocarbons preferentially enter micropores and are less prone to dissipation. (3) The main controlling factors for shale oil enrichment include retained hydrocarbon content, mobile hydrocarbon fraction, fluidity, and engineering-related parameters. Thick shale layers with high organic matter abundance, high proportions of light–medium hydrocarbons, and favorable porosity–permeability conditions, as well as interbedded siltstone, are enriched in mobile hydrocarbons. Full article

This work explores the key capabilities of emerging sensing technologies in the context of Structural Health Monitoring (SHM) of civil infrastructures, aiming to contribute to research on integrated and intelligent systems for more accessible and efficient monitoring solutions. As a case study, it focuses on the analysis of the static and dynamic behavior of the Edgar Cardoso stay-cable bridge during its rehabilitation, using fully customized transducers and equipment. The developed system integrates sensors capable of measuring accelerations, displacements, and temperature, which are connected to an autonomous data acquisition and transmission network. A digital interface was also developed to store, process, and visualize the collected data, enabling remote access for subsequent interpretation and analysis. The main contribution of this research lies in the use of optimized wireless monitoring systems with extended autonomy. This is achieved by employing edge computing techniques to minimize energy consumption during data transmission, as well as by managing the sleep modes of the sensor nodes. At same time, a methodology was proposed for the automatic and real-time estimation of axial forces in cables. This approach relies on the use of innovative edge computing tools, combined with the taut string theory as a simplified modelling framework. The results confirm the effectiveness of the developed system in achieving long-term operation without compromising monitoring performance. In addition, the developed system enabled the identification of the structure’s dynamic properties, particularly natural frequencies. The temperature profiles in critical sections, as well as displacements in the expansion joint were also measured and evaluated. The results demonstrate the potential of customized sensing solutions as effective tools for the management, maintenance, and long-term preservation of strategic infrastructures. Full article

Accurate prediction of the dynamic load-bearing characteristics of suction anchors is critical for the safety and reliability of floating offshore wind turbines. This study bridges the gap between mooring approaches and anchor foundation response assessment by systematically quantifying how the choice of mooring analysis method (dynamic or quasi-static) affects the predicted displacement response of suction anchors. Using OpenFAST coupled with a validated suction anchor dynamic response model (SADR), the motion responses of the suction anchor foundation for the OC4 semi-submersible platform are computed under regular waves of varying heights and periods, as well as irregular sea states representing operational and extreme conditions. The results reveal that the ratio of the anchor displacement predicted by dynamic mooring analysis to that predicted by quasi-static mooring analysis grows nonlinearly with increasing wave height and rises substantially as wave period lengthens, indicating that mooring dynamic effects become progressively more pronounced under large wave heights and long-period swell conditions. Statistical analysis under irregular waves further reveals that under moderate operational conditions, the response variability predicted by the two methods remains comparable; however, under extreme sea states, dynamic analysis yields not only larger peak displacements but also substantially greater response variability, with standard deviations significantly exceeding those obtained from quasi-static predictions. These findings provide quantitative evidence that the application of quasi-static mooring analysis to anchor foundation design carries a substantial risk of underestimating true responses, and that this underestimation becomes increasingly severe under high wave heights, long periods, and extreme conditions. The work establishes that dynamic mooring analysis is essential for reliable suction anchor foundations design and long-term serviceability assessment. Full article

Background/Objectives: The optimal surgical approach for displaced intra-articular calcaneal fractures (DIACFs) remains controversial. While the extensile lateral approach (ELA) has traditionally been preferred for complex fractures, the sinus tarsi approach (STA) has gained popularity due to its potentially lower soft tissue morbidity. However, comparative data focusing on patient-centered outcomes remain limited. This study aimed to compare clinical, radiological, functional, cosmetic, and complication outcomes between STA and ELA in Sanders type II–IV DIACFs. Methods: A retrospective comparative cohort study was conducted including patients treated with open reduction and internal fixation using either STA or ELA between February 2019 and October 2024. Functional outcomes were assessed using the AOFAS Ankle–Hindfoot Score and VAS. Radiological evaluation included Böhler and Gissane angles measured preoperatively, early postoperatively, and at final follow-up. Patient-centered outcomes included time to full weight bearing, return to work, heel width difference, and changes in shoe size. Complications were recorded throughout follow-up. Results: Baseline demographic and fracture characteristics were comparable between groups. Patients treated with STA demonstrated significantly shorter hospital stay, earlier progression to full weight bearing, and earlier return to work (p < 0.001). Functional outcomes favored STA, with significantly lower VAS scores and higher AOFAS scores at final follow-up (p < 0.05). No significant differences were observed between groups regarding Böhler or Gissane angles at any time point (p > 0.05). Wound-related complications were significantly more frequent in the ELA group (p = 0.018), although overall complication rates were comparable. Conclusions: The sinus tarsi approach was associated with comparable radiological restoration to the extensile lateral approach while demonstrating earlier functional recovery and lower wound-related morbidity. Given the retrospective and non-randomized design, these findings should be interpreted as associations rather than causal effects. STA may represent a safe and effective surgical option in appropriately selected Sanders type II–IV intra-articular calcaneal fractures. Full article

The global energy transition has fundamentally reshaped the conditions under which green trade generates sustainable productivity gains. This study investigates whether renewable energy adoption mediates the relationship between green trade export (GTE) and green total factor productivity (GTFP) across 37 OECD economies over 2003–2023. Employing two-way fixed-effects panel regression, dynamic System-GMM estimation, and Hansen’s panel threshold regression with 500 bootstrap iterations, we identify a nonlinear, inverted-N-shaped relationship between GTE and GTFP. Sequential threshold testing reveals a statistically significant double threshold structure: a first clean energy threshold at approximately 8.72% of total final energy consumption and a second threshold at approximately 24.63%, yielding three distinct productivity regimes. Below the first threshold, green trade suppresses GTFP through pollution displacement and insufficient absorptive capacity; between thresholds, green trade exerts a significant positive productivity effect driven by clean technology diffusion and innovation spillovers; above the second threshold, the positive effect moderates, consistent with diminishing returns to green technology absorption. Heterogeneity analysis reveals that early-stage energy transitioners bear disproportionately larger productivity penalties, while advanced transitioners capture stronger above-threshold gains. These findings underscore that trade liberalization alone is insufficient—sustainable productivity growth requires concurrent and targeted investment in renewable energy infrastructure under the post-Paris Agreement framework. Policy implications are presented as evidence-consistent hypotheses, acknowledging that the observational panel framework precludes definitive causal claims pending corroboration from quasi-experimental designs. Full article

We analyse pebble RFID tracing observations to investigate sediment transport dynamics in gravel-bed rivers using statistical modelling. This study examines a dataset of nearly 3500 tracer displacement measurements collected during 27 sediment-mobilizing events in a pre-Alpine reach in Italy. Our analysis follows three main steps, addressing tracer mobility patterns, event-scale transport dynamics, and reach-scale bedload inference. First, using Markov Chain analysis of state transitions on typical and high-magnitude transport events, we demonstrate that pebbles tend to maintain their mobility state between events, characterizing the between-event intermittency of bedload transport. A subsequent analysis of flow characteristics reveals that consecutive floods of similar magnitude exhibit increasing movement probability while maintaining similar virtual velocities. Finally, we train Gradient Boosting regression models to estimate distributions of pebble displacements and virtual velocities (defined, following common usage, as the ratio between the distance a tracer travels during a mobilising event and the duration of that event). Together with Monte Carlo propagation, these models are used to derive reach-scale volume estimates. The models identify flow rate and event duration as primary controls, while grain size has minimal influence within the sampled range of tracer dimensions. To strengthen our approach, we implement an extensive multi-stage validation process aimed at both single-tracer predictions and overall basin-scale movement estimates. The results indicate that high-magnitude transport events (12% of observations) contribute similar bedload volumes as typical events (88% of observations), highlighting the significant role of extreme events in total sediment transport. Model predictions yield bedload volume estimates that align well with independent measurements from a downstream sediment retention basin. Full article

This paper presents a finite element study of friction ring springs, with emphasis on the internal stress distribution between inner and outer rings and their damping capacity. A detailed two-dimensional axisymmetric model was developed and compared against experimental measurements, showing close agreement in load–displacement response. In parallel, the classical analytical approach was validated in terms of stress and deformation values. To enable efficient parametric studies, a reduced one-element finite element model representing the periodic structure of the spring was also developed. This simplified model reproduces the response of the complete axisymmetric model while reducing the computational cost by over 80%. Beyond reproducing global mechanical behavior, the study provides detailed insight into the ring interactions as a function of the cone angle, friction coefficient, and the ratio of inner to outer cross-sectional areas. The results show that an optimal design should favor higher circumferential stresses in the inner rings, as their compressive stress state and radial confinement make them more resistant to buckling and crack initiation than the outer rings, which are subjected to tension. The findings provide useful guidelines for the modeling and design of friction ring springs and contribute to the broader understanding of friction-based energy-dissipation systems. Full article

Tick-borne diseases pose a significant threat to global cattle production, with species displacement between ticks compounding this issue. This narrative review synthesises the literature to examine the drivers behind the expansion of the invasive Rhipicephalus microplus and its displacement of the native Rhipicephalus decoloratus in Southern Africa. We analysed the biological, ecological, environmental, and anthropogenic factors by reviewing existing scientific studies and reports. Our findings indicate that R. microplus possesses a competitive advantage due to its shorter life cycle, higher reproductive output, and greater acaricide resistance. Furthermore, anthropogenic activities such as communal grazing practices, unregulated livestock movement, and land-use changes facilitate the spread of this parasite. Climate change and vegetation shifts also create more favourable habitats for this invasive species. The conclusion is that the displacement of R. decoloratus by R. microplus intensifies the burden of tick-borne diseases, leading to substantial economic losses. Effective mitigation requires an integrated tick management approach that combines chemical, biological, and ecological strategies, supported by improved surveillance and farmer education. Full article

This article examines how mental health discourse functions as a credibility technology in Portuguese news reporting on sexual violence between 2014 and 2023. Using Critical Thematic Analysis and grounded in feminist media studies and critical mental health scholarship, the article analyses a qualitative corpus of reporting-oriented news items published in Público and Observador. The dataset consists of systematically selected articles in which mental health discourse functions as a substantive explanatory frame for sexual violence. Psychiatric, psychological, therapeutic, and metaphorical registers grant, withhold, or condition believability, allocating responsibility and organising care through norms of stability, risk, and expert verification. The analysis identified eight recurring discursive clusters through which mental health language stabilises truth claims: it can legitimise institutional authority, regulate survivors’ credibility, and explain perpetration through pathologising tropes, while often displacing structural accounts of gendered violence and reproducing ableist stigma. By specifying the credibility work performed by mental health discourse, the article contributes to debates on trauma-informed, survivor-centred, and anti-ableist reporting and proposes a transferable framework for analysing the sexual violence–mental health nexus in journalism. Full article

This study presents a comparative investigation of target displacement demands, a fundamental indicator in the seismic performance assessment of reinforced concrete frame systems, within the framework of the Turkish Building Earthquake Code (TBEC-2018), American standards (ASCE 41), and European standards (Eurocode 8). To analyse the consistency in performance levels stipulated by different structural design codes, critical variables, including soil class, number of stories, concrete grade, frame span, and soft story at ground level, were parametrically defined. The impact of these variables on the target displacement demands of the structures was examined through a comparative lens. Nonlinear static pushover analyses based on fiber-based modelling were conducted using SeismoStruct software to determine displacement demands under different seismic code formulations across six distinct variables. The displacements obtained for each variable at identical seismic ground-motion levels were evaluated individually. Analytical results reveal that soil degradation significantly increases target displacements across all codes. At the same time, the presence of a high story affects structural ductility and displacement demands, with varying sensitivities across the codes. Notably, it was observed that TBEC-2018 yields more conservative displacement demands in certain spectral regions than those in ASCE 41 and Eurocode 8. The findings provide critical data for understanding the disparities in safety margins among international seismic design standards. Full article

Human–elephant conflict (HEC) has emerged as a major conservation and socio-economic challenge across Asia, largely driven by habitat degradation and increasing human pressure within elephant ranges. In India, expanding agriculture, mining activities, and infrastructure development have progressively altered forest landscapes, restricting elephant movement and intensifying interactions with human settlements. This study examines the relationship between landscape dynamics and HEC in the West Singhbhum district, Jharkhand, India. A three-year field investigation (2018–2020) across four forest divisions—Porahat, Chaibasa, Kolhan, and Saranda—was integrated with multi-temporal land-use and land-cover (LULC) analysis from 2000 to 2020 to evaluate habitat changes and their influence on conflict patterns. During the study period, 157 human casualties and extensive crop and property losses were recorded, indicating the severity of the conflict in the region. Landscape analysis revealed a substantial decline in dense forest cover and a reduction of large core forest areas (>500 acres), accompanied by increasing agricultural expansion and forest perforation. NDVI trends further indicated widespread deterioration in vegetation condition, reflecting declining habitat quality. These structural landscape changes have fragmented elephant habitats and displaced movement routes toward human-dominated landscapes and are thus associated with a spatial clustering of conflict events, particularly in the Chaibasa Forest Division. In contrast, the Saranda Forest Division retains relatively intact forest cores and supports more stable elephant habitat conditions. The findings demonstrate that HEC in the region is strongly linked to habitat fragmentation and declining vegetation quality rather than random elephant behaviour. Maintaining large contiguous forest blocks, restoring landscape connectivity, and implementing targeted mitigation strategies are therefore essential for sustaining elephant populations while reducing conflict with local communities. Full article

This paper presents a numerical investigation of vortex-induced vibration (VIV) of six elastically mounted circular cylinders in oscillatory flow, three smooth and three biofouled with triangular surface roughness elements. The study aims to characterise the influence of the longitudinal spacing ratio ($L/D=3,4,$ and $5$) on the two-degree-of-freedom (2DOF) vibration response at a constant Keulegan–Carpenter number of $KC=10$. Simulations are performed using the transient RANS equations with the SST $k–\omega$ turbulence model, and structural motion is resolved using a dynamic mesh approach. Lock-in behaviour is observed over the reduced velocity range $5\le U_r\le 10$. Biofouled cylinders generally exhibit higher in-line displacement amplitudes than smooth cylinders in the initial and lower lock-in branches, whereas smooth cylinders tend to attain higher in-line amplitudes in the upper lock-in branch. The spacing ratio $L/D$ is found to significantly influence the response, with peak vibration amplitudes varying non-uniformly across the array and no single spacing configuration being optimal for all cylinders. This behaviour is further supported by analyses of trajectories, frequency content, and vorticity fields. Among the smooth cylinders, the middle cylinder exhibits the largest in-line displacement amplitude of $3.28D$ at $L/D=5$ and the largest cross-flow displacement of $1.34D$ at $L/D=3$. For the biofouled configurations, the middle and upstream cylinders show the highest in-line displacement amplitude of $2.69D$ at $L/D=4$, while the maximum cross-flow displacement of $1.27D$ is observed for the upstream cylinder at $L/D=5$. Full article