Search Results (14,016)

The increasing frequency and intensity of extreme climate events have posed more geohazards worldwide. It is therefore crucial to quantify and map risk to reduce disaster-related losses. The main objective of this study is to propose a quantitative framework to conduct risk assessment of buildings and infrastructures impacted by geohazards. A debris flow hazard in Tianjin, North China was taken as a case study. A physically based model and the Gumbel extreme value distribution were utilized to construct a range of extreme rainfall and runoff scenarios. The FLO-2D and ABAQUS software were subsequently employed to simulate the surging behavior of the debris flow and assess the structural vulnerability of buildings, respectively. Furthermore, the number of elements at risk and economic values were estimated to generate risk maps. The results revealed that variations in peak discharge in the channel evidently affected flow velocity and depth, thus elevating the debris flow intensity and the likelihood of the materials threatening buildings. The stiffness degradation of concrete was strategically used as the indicator to quantify structure vulnerability and effectively present the dynamic responses under the impacts of the debris flow. Under a 100-year return period rainfall scenario, the proportion of very high- and high-risk areas reached 31%, with the estimated economic loss approximately ¥167.7 million. This highlighted the critical role that extreme rainfall played in shaping both the spatial distribution and severity of debris flow risks. The proposed method provides a scientific basis for enhancing the resilience of mountainous regions to compound natural disasters exacerbated by climate change. Full article

This paper proposes a distributed vibration sensing system based on dual-chirped pulses and weak fiber Bragg gratings. Compared with conventional dual-pulse heterodyne detection techniques, the proposed approach utilizes the time-frequency characteristics of chirp signals, effectively relaxing the stringent requirements on the signal pulse width. In addition, when chirp signals with different chirp rates are adopted, frequency-division multiplexing technology can be realized to enhance the system’s response bandwidth. Last but not least, the sensing probe signal is generated in the optical domain using microwave photonic technology, which theoretically helps alleviate the dependence on arbitrary waveform generators. A simulation study on the system was conducted. Using a chirp signal of 200 MHz/μs and with a grating spacing of 50 m, the desired vibration signal is phased modulated onto a beat signal with a frequency of 100 MHz, and the allowable pulse width can be up to 500 ns. To verify frequency-division multiplexing capability further, an additional pair of chirped pulses with a chirp rate of 400 MHz/μs was introduced into the system, which was generated by frequency multiplication. The results demonstrate that the system response bandwidth is increased to twice the original bandwidth. The proposed scheme provides a new solution for performance enhancement in a distributed fiber optic vibration sensing system. Full article

The integration of renewable energy sources (RESs) into modern power systems has introduced significant challenges in maintaining system stability and reliability. Among these challenges, load frequency control (LFC) has become a vital area of research. The variable nature of RESs, such as wind and solar, along with their intermittent availability, necessitates advanced management systems for effective frequency regulation. LFC plays a crucial role in ensuring the stability and performance of electrical power systems by managing frequency through the balance of supply and demand, accounting for variations in load, generation, and other disturbances within the system. In traditional power systems, LFC is achieved through a combination of primary, secondary, and tertiary control mechanisms. However, the advent of smart grids has considerably complicated and enhanced the potential for LFC. In these smart grids, which leverage digital communication, sensors, and automation technologies, LFC becomes more intricate and adaptable. These systems not only utilize traditional centralized control but also incorporate RESs, decentralized resources, energy storage solutions, and real-time data to improve frequency management. This research methodically evaluates current LFC techniques using a hierarchical control and technology-focused framework, classifying approaches as conventional, intelligent, and hybrid control schemes within centralized and decentralized system architectures. An evaluative analysis reveals that while intelligent and hybrid control strategies markedly enhance dynamic frequency response and robustness with substantial renewable energy source (RES) integration, persistent challenges remain regarding controller coordination, scalability, computational requirements, and real-time execution. The analysis highlights adaptive hybrid intelligent control schemes, namely those that combine data-driven learning with physical system models, as the most promising avenue for future research, particularly in low-inertia and highly dispersed smart grid scenarios. Full article

Background/Objectives: With increasing life expectancy, interest in healthy aging has grown substantially. Dietary habits are among the key factors that contribute to achieving healthy aging. This study analyzes the relationship between dietary habits and the age–health association in older adults, using the first two years of data from an ongoing annual cohort study conducted in a region of Japan. Methods: We used observational data from approximately 1200 community-dwelling males and females aged 55 to 75 at baseline, drawing on the first two years of a ten-year annual cohort study conducted from 2023 to 2032. First, dietary habits were classified using an ordinal latent block model (OLBM), a model-based clustering approach applied to food frequency questionnaire (FFQ) data. We then examined whether the age–health gradient—measured across 33 indicators—differed significantly across the derived dietary habit types, using random effects models. Results: Dietary habits in the analyzed sample were categorized into six distinct types. Parameter estimates from the model suggest that the extracted patterns represent a continuum ranging from low to high dietary diversity. Regression analyses indicated that, in females, a negative association between age and LDL-C levels was observed among those with highly diverse dietary habits. Conclusions: The data-driven classification of dietary habits based on FFQ responses highlights the potential importance of dietary diversity. Full article

In grid-connected inverter systems, the Phase-Locked Loop (PLL) is fundamental for achieving and maintaining precise synchronization between the inverter and the electrical grid. Developing an efficient and robust PLL is essential to ensure reliable operation, particularly in the presence of abnormal grid conditions. Among the existing synchronization methods, the Synchronous Reference Frame-based PLL (SRF-PLL) is widely adopted due to its robust performance; however, it suffers from degraded accuracy under unbalanced voltage conditions. To address this limitation, the Second-Order Generalized Integrator-Quadrature Signal Generator (SOGI-QSG) was proposed in previous studies as an alternative approach. Despite its advantages, the SOGI-PLL exhibits weak filtering capability for lower-order harmonics and remains sensitive to DC offset, both of which can affect synchronization quality. As a result, numerous advanced PLLs based on SOGI-QSG have been proposed in the literature to address SOGI-QSG limitations by enhancing DC offset rejection, filtering capability, and dynamic response. This article provides a comprehensive assessment of various three-phase PLLs based on SOGI-QSG under unbalanced grid conditions, focusing on peak-to-peak frequency error, filtering performance, and DC offset rejection. The operational principles and mathematical models of each technique are discussed, and their performances are validated using MATLAB/Simulink (R2025b). The results show that the SRF-PLL exhibits oscillatory behavior under unbalanced conditions, whereas the PLLs based on SOGI-QSG demonstrate stable synchronization with different trade-offs between filtering strength and dynamic response. Therefore, the selection of the appropriate PLLs based on SOGI-QSG depends on the priorities of the specific application. Full article

Background and Objectives: Essential tremor (ET) is the most prevalent movement disorder, yet its neurophysiological basis remains incompletely understood. Emerging evidence indicates that ET may involve non-motor manifestations, including auditory dysfunction. Given the anatomical convergence of tremor-related and auditory pathways at the brainstem level, electrophysiological assessment of the auditory system may provide insights into ET pathophysiology. This study aimed to evaluate auditory pathway function in patients with essential tremor using conventional audiometry, brainstem auditory evoked potentials (BAEP), and medium-latency auditory evoked potentials (MLAEP), and to examine their associations with tremor characteristics. Materials and Methods: Thirty patients with ET (mean age 56.6 ± 19.2 years; 15 women) and 30 healthy controls with similar age and sex distribution underwent pure-tone audiometry, BAEP, and MLAEP recordings. Tremor severity and distribution were assessed using a standardized evaluation based on the Fahn–Tolosa–Marin Tremor Rating Scale. Results: Conventional audiometry demonstrated normal hearing thresholds in 63.3% of ET patients and 83% of controls, while sensorineural hearing loss was observed in 36.6% and 16.6%, respectively (p > 0.05). High-frequency hearing loss (HFHL) was significantly more prevalent in the ET group (p = 0.003). BAEP analysis revealed significant prolongation of peak latencies in right-sided waves II and III and left-sided waves I and II in ET patients compared with controls (p < 0.05), whereas interpeak latencies (I–III, III–V, I–V) did not differ between groups. MLAEP latencies (Na, Pa, Nb) showed no significant differences between ET patients and controls (all p > 0.05) and were not associated with tremor severity, disease duration, or hearing asymmetry. Conclusions: High-frequency hearing loss is more prevalent in essential tremor, and selective BAEP latency changes observed in the context of preserved interpeak intervals suggest predominantly delayed peripheral auditory input rather than a primary brainstem conduction abnormality. Preserved MLAEP responses indicate relative sparing of thalamocortical auditory processing, supporting the concept of essential tremor as a multisystem network disorder in which altered auditory input may interact with broader network-level mechanisms. Full article

Age-related cognitive impairment represents a critical stage in the continuum of neurodegenerative disorders, including Alzheimer’s disease (AD), highlighting the need for objective and non-invasive physiological indicators of early neurological change. This study investigates the simultaneous analysis of microsaccadic eye movements and pupil size variations as ocular biomarkers associated with age-related cognitive impairment using eye-tracking technology. A total of 70 participants were recruited and categorized into three age groups: individuals in their 20s, 60s, and 70s. Participants in their 70s were further categorized based on MMSE-K scores into cognitively normal (≥24) and impaired (≤23) subgroups. Quantitative analyses showed a significant age-related increase in microsaccade frequency along both axes, with significantly higher microsaccade frequencies (p < 0.01) among individuals with lower cognitive scores within the same age group. Pupil size variation, including constriction and dilation rates, declined with age, while response speed remained relatively unchanged across all age groups. These findings highlight a clear association between age related-cognitive decline and involuntary ocular responses. The proposed dual-biomarker method offers a non-invasive and quantitative framework that may complement traditional cognitive screening tools. Future studies involving larger cohorts and clinically diagnosed AD populations are required to determine the diagnostic utility of these ocular biomarkers. Full article

This review summarizes current scientific knowledge on the use of protein hydrolyzate-based biostimulants in fruit production through evidence mapping, cross-species comparison, and evaluation of protocol-dependent responses within an agronomic framework, centered on foliar applications and their role in sustainable production systems. Research across a broad range of fruit species reports that protein hydrolyzates can significantly enhance yield, improve fruit quality, and mitigate the adverse effects of abiotic stresses such as drought and high temperatures. Treated plants often exhibit improved nutrient uptake, increased photosynthetic efficiency, and enhanced morphological traits, including better root development and vegetative growth. However, the effectiveness of these biostimulants varies depending on the fruit species, developmental stage, and application frequency, indicating the need for more tailored and crop-specific protocols. In conclusion, the literature confirms the functional role of protein hydrolyzates in enhancing resilience and productivity in fruit crops, while highlighting the need for further research to optimize their use under diverse agroecological conditions. Protocol harmonization and robust field validation will be essential for improving the reliability, interpretability, and practical relevance of future research on protein hydrolyzates in fruit production. Full article

Full-annular rubbing is a common rubbing form in rotor systems. It introduces an additional constraint on the rotor, which produces a significant increase in the resonance frequency. Although many studies have qualitatively discussed the influence of rubbing on rotor dynamics, the quantitative effect of this constraint still needs to be analyzed with advanced methods and validated by rigorous experiments. The present paper aims to establish a method for predicting the resonance frequency of a rotor undergoing full-annular rubbing. The dynamic feature of a rubbing rotor system is analyzed by complex nonlinear modal analysis, and the numerical results are evaluated against measurements obtained from a rubbing rotor test rig. A modified Jeffcott rotor model is first formulated to clarify the relationship between the modal characteristics and the steady-state response. Experiments are then carried out to investigate the influence of rubbing on rotor dynamics. The results show that the constraint effect caused by rubbing can be quantitatively captured by nonlinear modal analysis. Full article

Background/Objectives: Disasters have a substantial impact on health systems and populations worldwide, with increasing frequency, mortality, and economic losses associated with natural hazards. The United Nations emphasises that disasters result from the interaction between hazards, exposure, and vulnerability, requiring integrated, people-centred health responses aligned with the 2030 Agenda. However, empirical evidence describing specific nursing interventions, particularly during response and recovery phases, is limited. This study aims to analyse the fundamental nursing care interventions provided to disaster victims in the Autonomous Region of Azores, Portugal. Methods: A qualitative multiple case study was conducted using documentary analysis of the nursing records from two disaster survivors with different clinical trajectories. Data were collected between August 2023 and May 2024 through complete transcription of nursing documentation contained in the clinical files. Data analysis followed Yin’s case study methodology and was theoretically supported by the Fundamentals of Care Framework. Results: The findings indicated a predominance of interventions addressing physiological needs during the acute phase, which progressively evolved to maintenance, psychosocial support, and adaptation needs during prolonged hospitalizations. Nursing care integrates advanced technical skills with relational and person-centred interventions, including emotional support, therapeutic communication, and promotion of patient autonomy. Conclusions: Nursing practice in disaster situations should be conceptualised as integrative, person-centred care grounded in international nursing frameworks. Strengthening disaster-specific nursing education, developing phase-adapted care protocols, and promoting multicentre longitudinal research appear to play a critical role for advancing nursing care models and informing health policies in disaster-prone regions. Full article

Background: Sepsis is one of the leading causes of early death after a liver transplant, with a frequency of up to 45% and a high death rate of 50% in more severe forms. Standard diagnostic and therapeutic algorithms are often not applicable to this specific population, where immunosuppression, reperfusion injury, and systemic inflammation overlap and generate a clinical picture that is significantly different from sepsis in immunocompetent patients. Methods: This paper analyzes the available literature and clinical experiences of characteristic immune and hemodynamic profiles of sepsis after liver transplants. Biomarkers (IL-6, IL-10, HLA-DR, lactate, and IgM) are discussed as tools for assessing immune status and guiding timely interventions, including the early application of continuous renal replacement therapy (CRRT) and the selective use of IgM-enriched immunoglobulins. Results: Sepsis after liver transplantation frequently unfolds in two phases, an initial hyper-inflammatory response driven by cytokine release and reperfusion injury and a second phase of secondary immunoparalysis characterized by reduced HLA-DR expression and increased anti-inflammatory signaling. The immunometabolic shift appears to influence the clinical course and may inform therapeutic decision-making. The immunoparalysis phase is accompanied by mitochondrial dysfunction and impaired vascular reactivity. This type of mechanism contributes to hemodynamic instability and a reduced response to standard therapy. Individualized monitoring and early use of hemofiltration and immunomodulatory measures can improve results in carefully selected patients. Conclusions: In this setting, an individualized immunometabolic approach may complement standard sepsis management in liver transplant recipients. The introduction of biomarkers of immune function into routine practice and the recognition of early signs of exhaustion of the immune response can assist in timely therapeutic decision-making and improve survival. Full article

Color metaphors may shape how people mentally represent abstract legal values such as justice and thereby influence legal socialization and law-related cognition. We tested whether black/white color terms are metaphorically linked to justice conceived specifically as a legal value, and whether these linkages vary with task demands. In two preregistered experiments that controlled for affective valence, word frequency, and semantic relatedness, Experiment 1 employed a Stroop-style lexical-judgment task with law-relevant terms and found faster responses to justice-related (legal) words than to injustice-related words and higher accuracy for white-colored stimuli, but no reliable color × meaning interaction—suggesting the absence of an automatic color–justice congruency effect during early, automatic processing. Experiment 2 used a translation-matching paradigm in which participants selected black or white translations for unfamiliar foreign words; here, participants systematically matched justice-related (legal) items with white and injustice-related items with black at rates above chance, revealing explicit color–justice associations. Together, the results point to a robust mental linkage of white with justice as a legal value, while black–injustice mappings emerge primarily under explicit selection demands. These findings suggest that black/white color metaphors organize law-related moral cognition but are flexibly activated depending on cognitive task and processing level. Full article

Railway transport is increasingly promoted as a sustainable and low-carbon mode of transportation. However, track-induced vibration propagation remains a significant challenge, particularly in metro systems situated near residential areas, where vibrations can transmit through the infrastructure into nearby buildings, disturbing residents and damaging structures. This study aimed to evaluate the cause of the significantly different vibration impact on nearby buildings caused by two nominally identical adjacent slab tracks on a metro line in Austria. Controlled weight drop tests were carried out in both track directions, and accelerations were measured to characterize wave transmission and energy dissipation. The data were processed using frequency response functions and Short-Time Fourier Transform to extract time–frequency signatures, modal parameters, and propagation delays. A three-dimensional finite element model of the railway superstructure was then calibrated against the experimental modal properties and transfer functions and used to simulate cracking or stiffness loss in the sleeper–slab region. The simulations reproduced the observed increase in slab acceleration and underground strain energy, linking the anomalous vibration transmission to hidden stiffness loss rather than to global design differences. Overall, the study demonstrates that combining impact testing, advanced signal processing, and calibrated finite element modelling provides an effective framework for diagnosing track defects and guiding the design and maintenance of more sustainable, low-vibration urban rail infrastructure. Full article

Accurate fault diagnosis of gear transmission systems is crucial for ensuring mechanical reliability and preventing catastrophic failures. However, existing research predominantly focuses on single-gear crack faults, often overlooking the complex coupling effects when cracks occur simultaneously on meshing gears in practical engineering scenarios. To address this research gap, a multi-degree-of-freedom dynamic model incorporating time-varying mesh stiffness under normal, single-crack, and coupled-crack conditions is established. Experimental validation is conducted based on an FZG closed test rig for power flow. The results indicate that the mesh stiffness under coupled-crack conditions is generally lower than that under single-crack conditions. In the time-domain vibration response, the periodic impact amplitudes induced by coupled cracks are significantly amplified, with the impact period jointly influenced by the rotational speeds of both the driving and driven gears. According to frequency-domain analysis, coupled cracks result in a notable increase in harmonic peaks of the mesh frequency, enhanced sideband amplitudes, and a modulation period that is between the rotational frequencies of the driving and driven gears. The simulation results from the dynamic model show high consistency with the experimental signals in terms of time-frequency characteristic trends and time-domain indicators such as the crest factor, thereby validating the effectiveness of the dynamic model. This study elucidates the unique influence mechanism of coupled cracks on the dynamic behavior of gear systems and can provide theoretical guidance for the accurate diagnosis and condition assessment of multi-tooth faults in subsequent research. Full article

This paper presents a high-sensitivity two-dimensional fiber-optic hydrophone designed for the detection and localization of underwater acoustic sources. The device comprises two sensing heads, each incorporating a fiber Bragg grating (FBG) embedded within a customized 3D-printed encapsulation. To enhance acoustic sensitivity, the design utilizes a silicone thin-film coupled with a pyramidal channel that spatially concentrates acoustic energy from the base to the apex, where the FBG is positioned. Incident acoustic pressure induces vibrations in the film, which are amplified by the channel structure, imparting strain on the FBG and resulting in a shift in the Bragg wavelength. The acoustic frequency response is demodulated by converting the overlapping optical power between the sensing and reference gratings into an electrical signal via a photodetector. By arranging the two sensing heads orthogonally, the system effectively determines the direction and angle of the acoustic source. Experimental results show a peak sensitivity of −210.59 dB re 1 V/μPa, with a FWHM of 57.92–66.27 Hz and a figure of merit (FOM) up to 3.64 dB/Hz. In addition, the acoustic-field SNR is approximately 26 dB in the dominant band, and the LOD is 64.19 dB re 1 μPa (10–400 Hz). Experimental validation confirms the hydrophone’s high sensitivity and localization accuracy, demonstrating its significant potential for underwater acoustic sensing applications. Full article