Search Results (94,559)

Single-lap shear joints made from fabric T300/polyphenylene sulfide (T300/PPS) and unidirectional T700/low-melt polyaryletherketone (T700/LM-PAEK) laminates are joined via induction and conduction welding at different processing temperatures. The joints are tested experimentally to investigate the influence of the processing temperature on the damage evolution in the specimens which is tracked using digital image correlation. Cracks grow rapidly in the unwelded parts of the joint interface but assume a stable steady-state propagation rate when reaching the fully welded overlap region. It is found that higher welding temperatures lead to longer weld lengths, which improve the strength and stiffness of the specimens and delay damage initiation. An accelerated crack growth rate indicates that the structure is close to its ultimate load after which the joint fails abruptly as the crack growth becomes unstable. Induction welding temperatures at the upper end of the recommended processing window (330 C for T300/PPS and 385 C for T700/LM-PAEK) result in the joints with the highest load-carrying capacity and slowest crack propagation, but also the least damage tolerance. Full article

Vehicle-sharing platforms are constantly gaining ground in smart cities around the world, reducing the number of traditional fuel-based vehicles on the roads in busy areas and thus contributing to the development of a sustainable environment. On the other hand, the availability of a plethora of shared vehicles of different types across a city increases the need for their seamless combination, so that they are considered part of a unified transportation system within a smart city rather than independent solutions. In this work, we present a system that enables authorized users to gain access to shared vehicles of different transport modalities, allowing them to reach their destination without relying on a private car or public transport. For this purpose, we have used existing systems and techniques from different fields, such as recommendation systems, machine learning, and route planning, which provide appropriate multimodal routes while taking into consideration several parameters, including user demographics, vehicle status, environmental conditions, and road traffic congestion. The evaluation of the system using simulated data showed that it enables users to identify suitable multimodal routes, either through explicit preferences or by inferring them from historical data, and revealed limitations to be addressed in future work. Full article

In pico-hydropower, the use of pumps as turbines is a cost-effective solution, especially for remote areas. The abundant seawater makes it a good fluid for pumped storage. The operation of centrifugal pumps in normal and reverse modes involves thickness loss because of solid particle concentration and vapor cavitation. Some research has been performed to predict cavitation in centrifugal pumps, but this issue still exists in several pico-hydropower plants. Therefore, to analyse the synergy between erosion and cavitation in a seawater centrifugal pump, we performed a CFD analysis to compute the effect of material mass loss due to erosion on cavitation risk. The Euler–Lagrangian method was used to track the released particles combined with the RNG k-ε turbulence model. The first part studied the effect of the surface mean roughness height (R_a) on the performance of the centrifugal pump. Increasing R_a from 0 to 15 μm decreases the pump hydraulic efficiency from 93% to 91%, respectively. The second analysis focused on the distribution of erosion thickness and its temporal evolution for 40 μm and 50 μm particles. For both the pump mode and the turbine mode, the erosion thickness is a polynomial function of power 2 with time. The most eroded regions are the blade leading edge (LE) and the blade trailing edge in pump and turbine mode, respectively. The last section focuses on analysing the effect of erosion thickness on cavitation damage. As the surface roughness increases, the cavitation damage power increases. The cavitation power risk increases from 111 kW to 156 kW in pump mode. In turbine mode, when the erosion thickness is between 0.0011 μm and 0.0022 μm, the cavitation damage is the same, approximately 170 kW, whereas the total gas distribution is uniformly distributed in the blade channel. With respect to seawater, the NPSHr increased compared with that with freshwater, from 3.35 m to 3.67 m. Full article

To investigate the battery impedance variation after the occurrence of nail penetration, this paper adopts Dynamic Electrochemical Impedance Spectroscopy (DEIS) for real-time monitoring of the impedance changes of lithium-ion batteries during the nail penetration process. A piecewise multi-frequency superimposed sinusoidal excitation is designed, which not only complies with the stability principle of battery testing but also ensures the signal-to-noise ratio of the excitation signal. By injecting the designed excitation signal into the operating battery and combining it with the rapid DEIS generation technology, the acquisition of DEIS data within the target frequency band in a short time is realized. Based on the obtained DEIS data, a fractional-order model is established and fitted for analysis before and after nail penetration. The results show that the steel nail introduces inductive reactance and impedance to the battery. Due to the parallel connection between the steel nail and the internal resistance of the battery, the overall impedance decreases, exhibiting a short-circuit state, and both the real and imaginary parts of the impedance experience an abrupt change at the moment of nail penetration. Considering the characteristic of abrupt impedance change of the battery after nail penetration, a battery nail penetration detection method based on DEIS is proposed. Considering the abrupt change characteristics of battery impedance after nail penetration, this paper proposes a battery nail penetration detection method based on DEIS. This method can effectively solve the problem of low sensitivity of traditional voltage monitoring methods in detecting nail penetration during battery operation. It has higher sensitivity and faster response speed compared with traditional methods, enabling online monitoring of battery states. Additionally, this paper also explores its potential application in real-world vehicles. Full article

Groundwater level (GWL) variations in the arid regions of Northwest China are driven by both natural processes and human activities. Identifying causal links between hydrological variables is fundamental to understanding groundwater evolution and conducting dynamic simulations. This study integrates the Mann–Kendall test, Seasonal-Trend decomposition using Loess, and the Peter and Clark Momentum-threshold and Momentary Conditional Independence (PCMCI) causal inference to analyze GWL variation characteristics and causal response processes across seven sub-basins in the Tarim Basin using multi-source remote sensing data. Results show an overall decline in GWL, primarily in the north-central part of the basin, with the Kaidu–Konqi River Basin reaching a maximum rate of 0.51 m/year. The trend components reveal localized depletion alongside broad stability, while seasonal components exhibit three types of temporal shifts in fluctuations. A mismatch exists between the prevalence of environmental influences and their causal strength. Daytime land surface temperature (LST_D), surface runoff (RO), and evapotranspiration (ET) show the highest detection frequencies, yet volumetric soil water in layers 2 (SWVL₂) and RO exhibit the largest ranges in strength and drive variations at specific sites. Response times are asymmetric. Negative effects from ET on GWL transmit quickly, while positive recovery is slow. Conversely, positive recharge from volumetric soil water in layer 1 (SWVL₁) is faster than its negative lag. At the basin scale, surface processes recharge GWL while mediating indirect influences from other variables. Climate and agricultural irrigation act as direct sinks. Depending on local conditions, three regional patterns emerge: direct climate-driven depletion, obstructed shallow water retention, and indirect compensation from agricultural water use. Causal networks indicate that RO and SWVL₁ have the highest centrality and dominate water output, whereas SWVL₂ acts as a passive receiver. Pathways from the surface to GWL are also asymmetric. The most frequent path involves step-by-step infiltration along RO → ET → SWVL₁ → SWVL₂ → GWL. In contrast, the paths with the highest cumulative strength are shorter and faster, specifically RO → ET → GWL and RO → SWVL₁ → GWL. The identified pathways and lag parameters provide a direct basis for groundwater dynamic modeling and water resource management in the basin. Full article

Damping modeling significantly influences the numerical seismic response of buildings, something that, despite being repeatedly emphasized in earthquake engineering research, is still overlooked even by seismic codes. It is a fact that, for simplification and ease of application, modern seismic design provisions assume damping for buildings entirely composed of a single material, e.g., reinforced concrete or structural steel. The current codes offer no guidance on damping assumptions for so-called mixed buildings comprising a lower part (stories) of reinforced concrete and an upper part (stories) of structural steel. Despite the growing use of mixed reinforced concrete-structural steel buildings, damping modeling of their seismic response remains almost unexplored. This study aims to contribute to this field by investigating the effect of different damping models on the elastic and inelastic seismic response of realistic three-dimensional mixed buildings. Modal response spectrum and time-history analyses served for this purpose. Key seismic response parameters, including interstory drift ratios, floor accelerations, and base shear demands, are extracted and systematically compared for the examined damping models. The results highlight the sensitivity of computed seismic demands to the assumed damping model. Guidance on selecting a damping model for the seismic analysis of mixed reinforced concrete-structural steel buildings is provided. Full article

Background/Objectives: Fingered citron (Citrus medica L. var. sarcodactylis (Siebold ex Hoola van Nooten) Swingle) is rich in phenolic constituents, yet systematic comparisons of free and bound phenolics across tissues and origins remain limited. This study compared the peel, pulp, and blend (whole fruit) of fingered citron from five Chinese regions: Zhejiang (ZJ), Yunnan (YN), Sichuan (SC), Guangdong (GD), and Guangxi (GX). Methods: Phenolic compositions were determined by colorimetric assays and HPLC. Antioxidant activity was assessed by ORAC and PSC, and hypoglycemic-related activity by α-glucosidase and α-amylase inhibition and glucose consumption in an insulin-resistant HepG2 (IR-HepG2) cell model. Results: Phenolic distribution followed the order peel > blend > pulp, and free > bound. HPLC identified 11 free and 5 bound phenolics, predominantly hesperidin, quercetin, and 5,7-dimethoxycoumarin. GX peel exhibited the highest free phenolic content (106.34 ± 0.23 mg GAE/100 g FW) and superior ORAC (30.56 ± 0.50 μmol TE/g FW), strongly correlating with total phenolics (r = 0.98, p < 0.01). Free phenolics showed stronger α-glucosidase and α-amylase inhibition, whereas bound phenolics produced higher glucose consumption in the IR-HepG2 cell model. The GX blend bound fraction showed the highest glucose consumption (5.48 ± 0.98 mmol/L). Conclusions: Under fresh-weight-based conditions, phenolic composition and in vitro bioactivities differed by fruit part, region, and phenolic fraction. Peel, especially GX peel, tended to show higher phenolic levels and stronger antioxidant-related performance, whereas the GX blend bound fraction showed the highest glucose-consumption-promoting activity. Full article

To investigate the inevitable aging of composite insulators under the coupled effects of electrical, thermal, ice, and fog stresses, as well as to explore their aging mechanisms and residual strength prediction methods, this study collected operational insulator samples from four environmental regions: Tibet, Yunnan, Hunan Xuefeng Mountain, and Anhui/Chongqing. Mechanical properties, including tensile strength, elongation at break, and shear resistance, were tested. The results indicate that the degradation of mechanical performance in composite insulation components can be attributed to the synergistic interaction of operational environments and material characteristics, with the aging behavior of high-temperature vulcanized (HTV) silicone rubber exhibiting significant non-linearity. Based on existing research, molecular dynamics simulations were employed to construct microstructural models at different aging stages, and it was verified that main chain scission, reduced system density, and changes in the elemental chemical environment during aging are closely related to the degradation of material mechanical properties. Based on hyper-elastic constitutive theory and fracture mechanics, a quantitative method for assessing the comprehensive aging degree was proposed, with “service years” and “operational altitude” as the core dimensions. A negative exponential model was established to describe the strength degradation of silicone rubber materials. This model enables the non-destructive estimation of the residual mechanical strength of in-service insulators in complex regions without power interruption, providing a decision-making framework for grid operation and maintenance. Full article

Spinal cord injury (SCI) is an acute, devastating neurologic condition that results in permanent progressive motor deficits, sensory disturbances, and autonomic dysfunctions, which limit function, participation, and quality of life. Although substantial progress has been made during the last several decades for both early trauma care and rehabilitation protocols following SCI, long-term neurological recovery remains unpredictable and often incomplete. This manuscript summarizes mechanistic and clinical evidence regarding robotic-assisted rehabilitation (RAR) and spinal neuromodulation (SN), which have been published since 2010 until the present time in a structured narrative review of the literature on these two emerging areas for neurorehabilitation after SCI. RAR provides high-intensity, task-specific training that consistently results in improvements in functional outcomes such as balance, coordination, and independence; however, its impact is limited when it comes to walking speed or voluntary motor control. SN (particularly epidural stimulation) can activate the residual neural pathways to standing up and stepping even after a complete injury but effects are typically stimulus dependent, with heterogeneous clinical results that often lack strong long-term evidence due in part to variability in patient selection, stimulation parameters and rehabilitation protocols. However, there is emerging mechanistic data supporting combining modulation of excitability through SN approaches along with structured sensorimotor training as an approach for enhancing recovery. Collectively, these findings support a shift toward more physiology-driven neurorehabilitation strategies and the need for future research to improve clinical translation and outcome predictability by patient stratification using standardized intervention protocols that include longitudinal evaluation. Full article

The development of effective source rocks is key to hydrocarbon accumulation. The Jinshan Rift Trough, located in the Ordos Basin, is generally considered to be a favorable zone for the formation of source rocks in the Mesoproterozoic Changcheng System. This study investigates mudstones of the Cuizhuang Formation (Changcheng System) from Well PT1 using petrological and geochemical methods to evaluate source rock potential and organic matter enrichment mechanisms. The results show that the original total organic carbon (TOC) and original S₁ + S₂ of the mudstone in the Cuizhuang Formation are 0.06–1.97% and 0.61–10.34 mg/g, respectively, and “good source rock” with a cumulative thickness of 6.7 m is developed in the lower part of the Cuizhuang Formation. The main hydrocarbon-forming organisms of the source rock are planktonic and benthic algae, among which planktonic algae account for a relatively high proportion. Equivalent vitrinite reflectance (R_o) exceeds 2%, indicating an over-mature stage. The TOC of the mudstone of the Cuizhuang Formation shows a weak relationship with the salinity and redox conditions of sedimentary water but has a significant correlation with the paleoproductivity and paleoclimate. Rather than anoxia or salinity, high productivity is the main controlling factor for the enrichment of organic matter in the Changcheng System. Under a warm–humid climate, increased surface runoff and terrestrial nutrient input promote the proliferation of bacteria and algae, leading to the formation and preservation of abundant sedimentary organic matter that forms “good source rocks”. This study provides a theoretical basis for the study of the petroleum system and oil and gas exploration in the Mesoproterozoic Changcheng System in the Ordos Basin. Full article

While substantial literature exists on COVID-19’s effects on businesses, long-term recovery strategies and support systems for informal female-owned enterprises in secondary cities are underexplored. The study sought to qualitatively examine the gendered impacts of COVID-19 on informal food businesses owned by women in Kenya. Qualitative interviews with 80 participants, including key informant interviews, in-depth interviews, and focus group discussions in Kisumu, Kenya, were conducted. The study found that the pandemic significantly disrupted the livelihoods of female vendors, leading to changes in the market and household organization, including gender specific transformations. The women adopted some individual and collective strategies as part of the post-pandemic recovery strategies to enhance their resilience in business. The study findings shed light on the vulnerabilities of informal food businesses in secondary cities to emergencies and the need for targeted policies to support informal economies during crises. Full article

The microwave permeability of composites containing microsized gadolinium powder in paraffin wax was studied as a function of frequency, temperature and gadolinium fraction for a series of composites with a powder volume fraction of 5% to 50%. The constitutive parameters of the composites were measured by the Nicolson–Ross–Weir technique in a standard 7 × 3 mm coaxial line in the frequency range of 0.1 to 10 GHz and the temperature range of 5 to 26 °C. In the indicated ranges, the permittivity was independent of frequency and temperature, and the real part of the permittivity only depended on the gadolinium powder volume fraction. It was found that the peak of the magnetic losses shifts towards lower frequencies with an increase in temperature. The Curie temperature of the composites found from the temperature dependence of the static permeability was close to 15 °C, being practically independent of the gadolinium volume fraction. To retrieve the intrinsic permeability of the filler particles, the Odelevsky mixing rule was used. The measured dependence of the static permittivity on the gadolinium volume fraction was in good agreement with the fitting by the Odelevsky mixing rule. Using the values of the percolation threshold and the depolarization factor obtained as a result of the fitting of the static permittivity, the frequency dependence of the intrinsic permeability of the filler particles was retrieved. The temperature effect on the intrinsic permeability was also analyzed. The obtained results may be useful for designing microwave devices, including temperature-tunable microwave screens and sensors. Full article

Local chicken breeds are increasingly being reconsidered as a means to produce distinctive meat in non-conventional systems while also supporting the conservation of endangered genetic resources. This study compared Banat Naked Neck (BNN) and Svrljig hen (SH), two Serbian indigenous breeds, reared under identical pasture-based conditions and slaughtered at 12 or 14 weeks. Carcass traits, including linear measurements and carcass composition, were evaluated in 40 males (10 per breed per age), while breast and thigh-with-drumstick meat quality (proximate composition and fatty acid profile) was analysed in 80 samples (10 per tissue per group). Data were analysed using two-way ANOVA, and multivariate patterns were explored using PCA and residual Spearman correlation analysis. BNN and SH showed similar slaughter weights, whereas slaughter at 14 weeks increased carcass conformation measures and conformation indices (p < 0.05). Breed differences were most evident in carcass part distribution and tissue partitioning within cuts: BNN had a higher breast proportion and breast meat yield, whereas SH meat was leaner and thigh with drumstick meat showed higher Σn − 3 and a more favourable Σn − 6/Σn − 3 ratio. PCA indicated clearer breed separation in thigh meat than in breast meat, consistent with the univariate lipid results, and residual correlations highlighted expected allocation trade-offs among carcass and cut components. Overall, slaughter at 14 weeks improved carcass value, and both breeds offer complementary traits for market-oriented conservation through use. Full article

Although atmospheric CO₂ concentration plays a crucial role in the climate system, the persistence of structural linkages among regions and the directional pathways through which they influence one another have not been systematically quantified. In this study, an interregional CO₂ concentration network across China is constructed using daily observations within a climate network framework. The results show that the network exhibits pronounced structural stability on multi-year timescales, with consistently high Jaccard similarity values between networks from different years. Network connectivity is dominated by zero and short time delays (within one day), indicating that regional CO₂ variations mainly exhibit coherent fluctuations on short temporal scales. Key source nodes and sink nodes are identified within the network. Strong source nodes are primarily located in Northeast China and parts of inland Northwest China, while strong sink nodes are mainly concentrated in the Xinjiang region, particularly around the Junggar Basin and the Tarim Basin. Pathway analysis using the Dijkstra shortest-path algorithm further reveals a dominant influence pathway extending from Northeast China toward Northwest China, with numerous pathways converging in the Xinjiang region. These findings offer a network-based perspective for examining the spatial influence structure of interregional CO₂ concentrations in China and emphasize the importance of cross-regional interactions in shaping regional atmospheric CO₂ variability. Full article

The digital economy empowers the development efficiency of the accessible industry, which is crucial for its sustainable development. Previous studies have focused on a single part of the accessible industry, lacking an overall grasp of the industry. Furthermore, they have not yet elaborated on the driving role of the digital economy in the accessible industry. This paper constructs an index system for evaluating the development efficiency of the accessible industry empowered by the digital economy, and uses sample data from 31 provinces (cities) in China. By comprehensively employing the three-stage DEA model method, this paper explores the reasons for the differences in development efficiency among accessible industries, empirically analyzes their influencing factors and the mechanism of efficiency improvement, and fills the gap in research on the digital economy’s impact on the accessible industry. The purpose is to deeply understand the development model of the accessible industry empowered by the digital economy through systematic evaluation and analysis, to accurately identify efficiency bottlenecks and clarify paths for improvement. Full article