Search Results (206)

Previous studies on tunnel fires have primarily focused on tunnels with flat ceilings and lacked studies on tunnels with beams. The present study is predicated on a reduced-scale tunnel model with a beam structure. Through meticulous analysis of the effects of factors such as longitudinal ventilation velocity and beam dimensions, the study unveils the distribution pattern of ceiling temperatures under the longitudinal smoke exhaust mode. The findings suggest that the presence of beams can induce turbulence in the longitudinal ventilation airflow. It has been demonstrated that the magnitude of this phenomenon is directly proportional to the spacing of the beams. This results in fluctuations in the ceiling temperature rise close to the combustion zone. The smoke storage capacity of the open cavities formed between adjacent beams is significantly affected by the beam height, thereby influencing the overall temperature rise beneath the ceiling. The greater the beam height, the higher the overall ceiling temperature rise near the combustion zone, but the lower the ceiling temperature rise downstream of the fire source. A prediction model for the longitudinal decay of ceiling temperature downstream of the fire source in tunnels with beams has been obtained. This model is related to the dimensionless beam dimension. Full article

This study evaluates adhesive bolts (chemical anchors) bonded with epoxy and vinyl ester resins for surface and tunnel excavations in tropical mining environments under static and dynamic loading. Over 300 pull-out tests in concrete and hard rock examined the effects of bolt length, curing time, and substrate condition on load capacity, failure mode, and bond–slip response. Epoxy anchors exhibited higher bond strength, including under early-age and thermally active conditions, while vinyl ester showed improved ductility and post-peak behaviour in fractured rock. Numerical modelling with Rocscience RS2 (Phase 2) and Unwedge simulated excavation responses for bolt lengths of 190–250 mm and spacings of 0.5–2.0 m. Tensile failure dominated at wider spacings, whereas closely spaced anchors enhanced confinement and redistributed stresses. The combined experimental–numerical evidence quantifies chemical-anchor performance in complex subsurface settings and supports their use for early-age support and long-term stability. Findings motivate integration of resin-grouted bolts into modern support designs, particularly in seismically sensitive or hydrothermally variable mines. Full article

This study examines al-Mufaḍḍaliyyāt anthology as a foundational corpus wherein pre-Islamic and early Islamic Arabic poetry emerged not only as a cultural artifact but as a generative locus for theological reflection. Through a close reading of selected poems and nuanced engagement with the figurative language specifically metaphor, personification, and symbolic narrative, the research situates poetry as a mode of epistemic inquiry that articulates religious meaning alongside Qurʾānic revelation. Drawing on ʿAbd al-Qāhir al-Jurjānī’s theory of semantic structure and metaphor, in dialogue with Paul Ricoeur’s conception of metaphor as imaginative cognition, the study proposes that poetic discourse operates as a site of “imaginative theology”, i.e., a space wherein the abstract is rendered sensorially legible and metaphysical concepts are dramatized in affective and embodied terms. The analysis reveals how key Qurʾānic themes including divine will, mortality, ethical restraint are anticipated, echoed, and reconfigured through poetic imagery. Thus, al-Mufaḍḍaliyyāt is not merely a literary corpus vis-à-vis Islamic scripture but also functions as an active interlocutor in the formation of early Islamic moral and theological imagination. This interdisciplinary inquiry contributes to broader discussions on the interpenetration of poetics and theology as well as on the cognitive capacities of literature to shape religious consciousness. Full article

Urban parks play a crucial role in promoting physical and mental health by providing green spaces for recreation, relaxation, and social interaction. However, access to these spaces is often constrained by the structure and performance of public transportation networks—particularly in megacities marked by spatial and social inequalities. This study evaluates equitable access to urban parks in Mexico City through the public transit system, using centrality-based metrics within a Geographic Information Systems (GIS) network analysis framework. Parks are categorized by size (small: 0.3–1 ha; medium: 1–4.5 ha; large: >4.5 ha), and three centrality measures—reach, gravity, and closeness—are applied to assess their accessibility via different transport modes: Metro, bus rapid transit (BRT), trolleybuses, public buses, and concessioned services. Results show that Metro stations are more connected to large parks, while BRT and trolleybus lines improve access to small and medium parks. Concessioned services, however, present fragmented and uneven coverage, reinforcing socio-spatial disparities in access to green infrastructure. The findings underscore the importance of integrated, multimodal transportation planning to enhance equitable access to parks—an essential component of urban health and well-being. By highlighting the spatial patterns of accessibility, this study contributes to designing healthier and more inclusive public spaces in the city, supporting policy frameworks that advance health equity and urban sustainability. Full article

In this paper, we introduce and study the concept of rough I–$\alpha \beta$–statistical convergence of order $\gamma$ in neutrosophic normed spaces. This new mode of convergence combines the principles of rough convergence, statistical convergence with respect to an ideal, and the flexible structure of neutrosophic norms to handle indeterminacy and vagueness in sequence behavior. We establish fundamental properties of this convergence type and investigate the structure of its limit set. Specifically, we prove that the set of rough I–$\alpha \beta$–statistical limit points of order $\gamma$ is convex and closed under certain conditions. We further analyze the relationship between cluster points and rough statistical limits in this context. The theoretical results are supported by illustrative examples to demonstrate the validity and applicability of the proposed notions. Our findings generalize several existing convergence concepts and contribute to the growing body of research in neutrosophic functional analysis. Full article

An efficient optimization method for designing defected ground structure (DGS)-based common-mode filters (CMFs) is proposed, utilizing equation-based transmission line models integrated with a genetic algorithm (GA). Designing an optimal DGS-based CMF using full-wave simulation tools is time-consuming due to its process-intensive nature. The proposed optimization method implements transmission line theory to allow for direct S-parameter calculation, enabling integration with an optimization algorithm to identify optimal parameters within a confined 5 mm × 10 mm design space. This work demonstrates a compact asymmetric DGS design to illustrate the method’s capability. The resulting compact asymmetric DGS-based CMF achieves wideband common-mode suppression with a –10 dB bandwidth from 3.18 GHz to 12.89 GHz. The optimization method significantly reduces design time by minimizing the need for lengthy and repetitive full-wave simulations. The measured S-parameters of the fabricated CMF closely match the simulated results, validating the model’s accuracy. Compared with traditional methods for designing DGS-based CMFs, the proposed method utilizes transmission line theory to optimize the design efficiently, providing a practical and efficient solution. Full article

In-band full-duplex (IBFD) technology has attracted significant attention for its potential to double the spectral efficiency by enabling a simultaneous transmission and reception over the same frequency channel. However, achieving high isolation between closely spaced transmit and receive paths remains a critical challenge. In this paper, a novel compact co-polarized monopole antenna with self-decoupling capability is proposed based on common-mode/differential-mode (CM/DM) theory. By innovatively folding the ends of the monopole elements, the antenna exploits the distinct behaviors under CM and DM excitations at a close spacing to achieve simultaneous impedance matching in both modes. This effectively enhances the isolation between antenna elements. The design enables self-interference suppression without requiring any additional decoupling structures, even under compact antenna and port spacing. Measurement results confirm that the proposed antenna achieves over 20 dB isolation within the 3.4–3.6 GHz operating band, with a compact spacing of 0.008 λ₀ (λ₀ corresponds to the wavelength at the center frequency). Full article

This article traces the development of video activism in Turkey over the past two decades, focusing on its transformation during and after the 2013 Gezi Park protests. Situating video activism as a form of radical media, it examines how activists have used digital recording technologies to document protests, amplify marginalized voices, and contest dominant narratives. Drawing on interviews with members of eight activist collectives, the article maps the evolving practices, ethics, and internal dynamics of video activism, paying close attention to tensions between visibility and security and between participation and professionalism. The Gezi protests marked a turning point, expanding video activism into a decentralized, diverse, and participatory field. In the aftermath, while collective structures weakened due to increasing repression and shrinking protest spaces, the use of video as a tool for testimony, expression, and archiving has continued to evolve. New actors, forms, and platforms have emerged, transforming video activism from a specialized practice into a broader, more diffuse form of engagement. This article argues that video activism remains a significant mode of mediated resistance, reflecting the challenges and the evolving potential of visual intervention in an ever-changing political landscape. Full article

Aerosols play a crucial role in air quality, climate regulation, and public health; their timely monitoring is hence fundamental. The aerosol optical depth (AOD) is the parameter used to investigate the spatial–temporal distribution of aerosols from space. Specifically, the AOD retrieved from the Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm applied to a Moderate Resolution Imaging Spectroradiometer (MODIS) is suitable for aerosol investigation at a local scale by exploiting its high spatial resolution (1 km × 1 km). In this study, the MAIAC AOD retrieval over Rome (Italy) was validated for the first time, using ground-based data provided by an AERONET station operating in a semi-rural environment close to the city, over a time series from January 2001 to December 2022. Moreover, AOD trends were evaluated in a study area encompassing Rome and its surroundings, characterized by a transition zone between urban and rural environments. The results show a general underestimation of the MAIAC AOD; specifically, the validation process highlighted the less accurate performance of the algorithm under higher aerosol loading and with predominantly coarse mode aerosol. Interesting results were obtained concerning the influence of the geometrical configuration of satellite acquisition on the accuracy of the MAIAC product. In particular, the solar zenith angle, the relative azimuth and the scattering angle between the principal plane of the sun and satellite synergistically influence retrievals. Finally, the spatial distribution of the AOD shows a decreasing trend over the 2001–2022 period and a strong influence of the city of Rome over the whole study area. Full article

The structural integrity of next-generation offshore wind turbines is highly sensitive to inflow variability, yet current standards often simplify wind conditions without capturing their combined effects on dynamic loads. To address this, we analyzed the NREL IEA 15 MW offshore wind turbine using 27 simulation cases strategically selected through Latin Hypercube Sampling (LHS) from a design space of over 14 million combinations. Four key environmental variables—Extreme Wind Speed (30–40 m/s), turbulence intensity (12–16%), Shear Exponent (0.1–0.3), and Flow Inclination Angle (−8° to +8°)—were varied to assess their influence on structural response using BLADED simulations. Results showed that the combined structural moment (Mxyz) ranged from 159,502.5 kNm (minimum) to 189,829.2 kNm (maximum), indicating a 19% increase due to inflow conditions. Maximum-moment case exhibited a 2.6× higher drag coefficient, a 13% rise in pitch bearing moment, and dominant frequency content near 0.175 Hz, closely matching the first tower side-side natural mode (0.17593 Hz), confirming potential resonance. These findings highlight the importance of multidimensional inflow modeling for identifying worst-case load scenarios and establishing a foundation for future load prediction models and support structure optimization. Full article

This article argues that environmental education must move beyond knowledge transmission to become a transformative, psychological, and relational practice. Rooted in the One Health framework, which emphasizes the interconnectedness of human, animal, and ecological well-being, this article positions curiosity as a central catalyst for ecological and psychological integration. While this article specifically engages with the One Health framework, the same integrative principles apply equally to the closely related Planetary Health perspective, emphasizing interconnected human, ecological, and planetary well-being. Drawing from Jungian and post-Jungian psychology, ecopsychology, and educational theory, it redefines curiosity as a symbolic, ethical, and affective mode of engagement with the Other, both within the psyche and in the more-than-human world. Through boredom, dialogue, narrative, and embodied practices, curiosity creates space for inner movement, narrative reconfiguration, and a relational mode of knowing that can confront ecological crises with imagination, patience, and integrity. This article offers pedagogical strategies to cultivate this deeper form of curiosity as a foundation for lifelong ecological engagement. Full article

The working accuracy of space optical payloads, sensitive components, greatly depends on the pointing accuracy and stability of the platform. This article establishes a mathematical model for relative position and attitude measurement based on PSD and eddy current and analyzes the failure modes under the measurement models. Through model derivation, it can be concluded that the position and attitude measurement system has high redundancy; in the event of sensor failure in the horizontal or vertical direction, relative position and attitude measurement and resolution can still be completed, which solves the relative measurement problem of position and attitude measurement of the space Maglev vibration isolation control system, providing high-precision closed-loop control for the control system to achieve high-precision pointing and stability. In response to the requirements of high-precision non-contact displacement and attitude measurement, eddy current sensors were selected, and a sensor circuit box was designed. The testing and calibration system adopts an eight-bar Maglev layout, and the actuator has unidirectional dual-mode output. The actuator adopts a double closed magnetic circuit structure, and the coil adopts a winding single-coil structure. The system includes a multi-degree-of-freedom high-precision coil spatial pose automatic positioning platform, a strong magnetic structure, strong uniform magnetic field magnetization, an integrated assembly testing platform, etc. According to the test data, the driver has strong linearity in both low- and high-current ranges. The relative output error in the low-current range does not exceed 0.1 mA, and the relative output error in the high-current range does not exceed 2 mA. After fitting and calibration, it can meet the design requirements. Within redundant designing, fault mode analyzing, and system testing, the relative measurement system can ensure the working accuracy of the optical payload of the spacecraft, which reaches the advanced level in the field. Full article

Walking is recognised as a healthy and sustainable mode of transport. Providing adequate infrastructure is pivotal for the promotion of walking and, subsequently, for achieving the benefits derived from its numerous positive effects. However, efficiently measuring the walkability at the street level remains challenging. In this paper, we present an indicator-based assessment model that can be used with open spatial data to evaluate segment-based walkability. The model incorporates eleven indicators describing the street segments and their close surroundings that are relevant for pedestrians, such as the presence and type of pedestrian infrastructure, road category, noise levels, and exposure to green and blue space. A weighted average calculation results in walkability index values for each street segment within a road network graph. The model’s generic approach and the ability to be used with open data ensure its reproducibility, adaptability, and scalability. The feasibility of the walkability model was shown using a case study for Salzburg, Austria. The model’s validity was evaluated through a large-scale study involving 660 full responses to an online survey. Participants provided ratings on the walkability of randomly selected street segments in Salzburg, which were compared with the calculated index, revealing a strong correlation (Spearman’s rank correlation = 0.82). Full article

This paper describes flight planning supported by modeling, guidance, and feedback control for an electric Vertical Take-Off and Landing (eVTOL) QuadPlane small Uncrewed Aircraft System (sUAS). Five Lift+Cruise sUAS waypoint types are defined and used to construct smooth flight path geometries and acceleration profiles. Novel accelerated coverage flight plan segments for hover (Lift) and coverage (Cruise) waypoint types are defined as a complement to traditional fly-over, fly-by, and Dubins path waypoint transit solutions. Carrot-chasing guidance shows a tradeoff between tracking accuracy and control stability as a function of the carrot time step. Experimentally validated aerodynamic and thrust models for vertical, forward, and hybrid flight modes are developed as a function of airspeed and angle of attack from wind tunnel data. A QuadPlane feedback controller augments classical multicopter and fixed-wing controllers with a hybrid control mode that combines multicopter and aircraft control actuators to add a controllable pitch degree of freedom at the cost of increased energy use. Multi-mode flight simulations show Cruise mode to be the most energy efficient with a relatively large turning radius constraint, while quadrotor mode enables hover and smaller radius turns. Energy efficiency analysis over QuadPlane plans with modest inter-waypoint distances indicates cruise or aircraft mode is $30\%$ more energy efficient overall than quadrotor mode. Energy-aware coverage planner simulation results show fly-coverage (cruise) waypoints are always the most efficient given long distances between waypoints. A Pareto analysis of energy use versus area coverage is presented to analyze waypoint-type tradeoffs in case studies with closely spaced waypoints. Coverage planning and guidance methods from this paper can be applied to any Lift+Cruise aircraft configuration requiring waypoint flight mode optimization over energy and coverage metrics. Full article

Radar observations of tropospheric and lower-stratospheric winds and density-normalized momentum flux made in northern Germany with two 53.5 MHz VHF MST radars over a period of one week in August 1986 are presented. One MST radar was a permanent installation, the SOUSY VHF Harz radar, located in the Harz Mountains, and the other temporarily installed about 27 km away from the Harz. The latter radar, the SOUSY VHF Lindau radar, was operated with a limited number of antennas and much-reduced power, making it effectively a tropospheric radar. Unusually, this small radar was successfully operated in Doppler beam steering (DBS) mode to measure winds and density-normalized momentum fluxes after correcting for biases in the beam look directions resulting from its small antenna aperture. We compared the winds and density-normalized upward fluxes in horizontal momentum measured using these two radars. The mean winds show good agreement between the two radars and with winds from radiosondes launched from Essen and Hannover. Density-normalized zonal momentum fluxes are similar in form between the two radars, but do show an offset when calculated over the entire observational period. Because of the agreement in form, the zonal mean flow accelerations calculated from them are similar, and so these results are consistent between the radars even though the topography is quite different. Although the observations were made many years ago, the results we present here are still of interest, because comparisons of closely spaced wind profiling radar observations are still relatively rare, radar measurements of tropospheric and stratospheric momentum fluxes are sparse, and the successful operation of a very small DBS radar operating in the lower VHF band is of particular interest from a technical perspective. Full article