Search Results (30,302)

Engine noise is a predominant source of noise in the cabin of internal combustion engine vehicles and new energy hybrid vehicles. The conventional multi-channel active noise control (ANC) system, based on the adaptive notch filtered-X least mean square algorithm, is commonly employed to mitigate such multi-tonal noise. However, the computational efficiency and convergence performance of this system may be significantly hindered by the large estimated secondary path length and the frequency-dependent convergence behavior. To overcome these limitations, this paper proposes a computationally efficient and fast-converging multi-channel ANC system by incorporating a local secondary path (LSP) equalization method. The proposed method enhances the convergence speed by equalizing the magnitude responses of estimated secondary paths and reduces the computational complexity through an improved LSP modeling approach. Accordingly, a set of low-order equalized LSP models with normalized amplitude-frequency responses is generated and employed for reference filtering. A computational complexity analysis comparing the conventional system, a recent cost-effective system, and the proposed system is presented. Numerical simulations are conducted to evaluate the convergence speed and noise attenuation performance of these three systems. Additionally, real vehicle experiments are performed using a digital signal processing controller. The results demonstrate that the proposed multi-channel ANC system achieves a superior noise reduction effect. Under accelerated conditions, the average attenuation of the second-order noise component at the four error microphones is measured at 4.4 dB(A), 6.2 dB(A), 13.4 dB(A), and 10.0 dB(A). These findings confirm the practical effectiveness of the proposed multi-channel ANC system. Full article

This paper investigates the influence of coarse particle size on pressure characteristics through horizontal pipe transportation experiments of coarse particles and sand-laden water. As particle size increases, the thin and long grain accumulation layer forming at the pipe bottom and particle clusters above the layer vanish, most grains roll and bounce more quickly, the instantaneous pressure fluctuation intensity increases exponentially, and the time-averaged pressure decreases linearly along the flow direction. The fluctuating pressure probability density tends to obey a Gaussian distribution, and the turbulence power below 16 Hz increases. After adding fine sand constituting sand-laden water flows, the instantaneous pressure fluctuation intensity, transportation energy loss speed and fluctuating pressure amplitudes increase. With increasing particle size, the fitted Gaussian distribution of the fluctuating pressure probability density changes from thin to short and wide, and the spectral power of the measured pressure fluctuations increases within the resolvable frequency range, especially in the range from 8 to 10 Hz. Full article

Mobile charging stations can deliver energy at the point of demand, but their isolated battery-to-battery DC–DC stages must accommodate independent source and load battery-voltage variation. This study develops a hierarchical, domain-wide analytical framework for a fixed-hardware 20 kW silicon-carbide phase-shifted full-bridge converter with a four-diode rectifier. The independently varied terminal domain spans 586–840 V at the source and 495–738 V at the load. The framework combines rated-power coverage, constraint-resolved derating, modeled semiconductor-loss screening, analytical commutation-capacitance budgeting, deterministic sensitivity assessment, and selected-point switching-level refinement. For four screened transformer turns ratios, nominal area-based rated-power can reach 95%. However, a three-point leakage-inductance sensitivity changes the nominal ordering at −10%, showing that the sub-one-percentage-point coverage separation does not establish a robust unique ratio. Selected-point commutation-cell and full-converter simulations show that the analytical added-capacitance screening bound is useful for rapid screening but can be optimistic near difficult high-source-voltage and light-load conditions. The full-converter results also retain high-capacitance light-load cases in which target power is not reachable at the phase-shift-domain boundary. The proposed evidence hierarchy therefore supports rapid candidate screening, identifies sensitive boundaries, and directs detailed switching refinement without claiming a universal transformer-ratio optimum or replacing hardware measurements. Full article

Road tunnels are highly carbon-intensive due to material use, energy-intensive construction, and long service lives, yet major gaps remain regarding emission hotspots, construction method comparisons, and regional differences, particularly in Central and Eastern Europe. This article combines a PRISMA 2020-guided systematic literature synthesis with a Polish case-study life-cycle assessment (ISO 14040/14044, cradle to grave, functional unit of 1 m of tunnel, 100-year horizon) using Ecoinvent factors and the Polish energy mix, covering material production, construction, operation, maintenance, and end of life. The literature synthesis found substantial variability in tunnel carbon emissions, ranging from 1500 to 22,062 t CO₂-eq per lane-kilometer depending on the construction method, tunnel type, and region. Material production was the largest contributor to construction-phase emissions (70–95%), with concrete and steel responsible for over 90% of material-phase impacts and 75–80% of construction-phase emissions, while operational energy use dominates over the full life cycle. Concrete and steel substitution (e.g., GFRP bars and calcium sulfoaluminate cement) offers the greatest construction-phase reduction potential, while operational measures, such as LED lighting, demand-controlled ventilation, and renewable energy, can cut long-term energy use by 30–50%. For Poland, low-carbon concrete, prefabrication, and renewable electricity could reduce tunnel emissions by 40–60%. These findings highlight pathways for decarbonizing tunnel infrastructure through material innovation, energy-efficient operation, and circular economy principles. Full article

Smart lighting is becoming a strategic component of intelligent and low-carbon urban infrastructure because it combines efficient illumination with connectivity, remote management, and continuous operational monitoring. This study proposes a reproducible unit-level methodological framework that transforms field records from a functional smart-lighting installation into traceable indicators of electrical performance, energy efficiency, avoided emissions, preliminary economic benefit, sensitivity, and conditional scalability. The approach treats the luminaire not only as an electrical load, but as a monitored urban energy node whose operation can be validated, characterized, and compared under planning-oriented control scenarios. The methodology integrates data preprocessing, electrical consistency assessment, representative baseline definition, scenario-based energy modeling, explicit environmental conversion, and conditional scaling to homogeneous lighting assets. The results reveal a stable electrical operating regime and show that managed operating conditions can generate sustained reductions in energy use and associated environmental impacts while preserving analytical transparency between measured variables and scenario-derived indicators. Sensitivity and multivariable analyses further support the robustness of the unit-level interpretation and highlight the value of monitored lighting data for comparative decision-making. The framework therefore provides a technically grounded reference for smart-city lighting management, energy planning, and scalable infrastructure assessment, with relevance to the objectives of SDG 7, SDG 11, and SDG 13. Overall, the study contributes an original data-driven perspective for integrating IoT-enabled lighting, remote supervision, and sustainability-oriented urban management within a common analytical structure. Full article

The textile dyeing and printing (TDP) industry in Zhejiang Province faces significant pressure to reduce conventional pollutants and carbon emissions. Dyeing and finishing (DF) are key links in energy consumption and pollutant emissions in the TDP industry. However, the trade-offs between pollution reduction and carbon mitigation remain poorly understood. This study evaluated five synergistic technology pathways using a hybrid life cycle assessment (LCA) approach. The pathways included low-carbon energy substitution, waste heat recovery, advanced wastewater treatment, intelligent process control, and integrated application. The IMPACT 2002+ method was used to quantify 7 environmental impact categories. The results showed that no single technology pathway achieved optimal performance across all categories. Scenario 3 (advanced wastewater treatment) reduced eutrophication potential by 54.97% but increased global warming potential by 18.00%. Scenario 5 (integrated application) achieved the best overall performance. It reduced non-renewable energy consumption by 30.90%, global warming potential by 32.69%, acidification potential by 26.08%, and eutrophication potential by 40.00%. The synergy coefficient of Scenario 5 was 1.08, indicating strong pollution-reduction synergy. Extrapolation to the provincial level showed reductions of 40% for COD, 39.76% for ammonia nitrogen, 40.78% for SO₂, 10.67% for NOx, and 14% for VOCs. These findings demonstrate that systematic technology integration can resolve the trade-offs inherent in individual pollution control measures under the conditions evaluated in this Zhejiang-based case study. This study provides scientific guidance for technology selection and policy formulation in the DF industry. Full article

Sarcopenia is a progressive skeletal muscle disorder in which clinically relevant muscle failure is expressed primarily as reduced muscle strength, with low muscle quantity or quality used to confirm the diagnosis and impaired physical performance indicating greater severity in the EWGSOP2 (European Working Group on Sarcopenia in Older People 2) framework. This narrative review first defines the clinical phenotype and its current diagnostic operationalization and then uses an author-proposed five-pillar framework: energy, structure, regeneration, neuromuscular control, and systemic communication, to organize the interacting biological mechanisms that may generate that phenotype. The framework is intended as a translational heuristic rather than a validated classification and is positioned within broader geroscience and hallmarks-of-ageing concepts. Particular emphasis is placed on the distinction between muscle mass, strength, power, and physical performance; context-dependent mTORC1 signaling; the limited specificity of candidate biomarkers; and the uncertain causal direction of several mechanistic associations. Resistance exercise and adequate energy and protein intake remain the foundations of management, whereas pharmacological and regenerative strategies have not yet demonstrated sufficiently consistent improvements in patient-relevant functional outcomes to replace these interventions. Linking biological mechanisms to measurable muscle failure may improve interpretation of current evidence and help define priorities for future mechanistic and clinical studies. Full article

Parallel converter operation enables flexible capacity expansion of energy-storage power conversion systems. However, parallel converter interactions, filter-inductor saturation, and grid-strength variations increase the risk of resonance instability. The measured current-inductance characteristic is incorporated into an operating-point-dependent closed-loop Norton model. The grid current of an individual converter is decomposed into self-reference, parallel converter coupling, and grid-voltage-disturbance responses. It reveals that converter-side inductance attenuation shifts the internal and parallel resonances to higher frequencies and increases resonance-instability risk, whereas converter number and grid impedance primarily reshape the parallel resonance. A coordinated active-damping method is then developed: PCC voltage feedforward weakens common-network interaction, and capacitor-voltage feedback increases local LCL-filter damping. Simulation and experimental results validate the feasibility and effectiveness of the proposed control method. Experiments with two parallel converters validated the proposed control method. Stable transient current responses were achieved during a simultaneous current-reference step from 50 to 120 A, while the grid-current THD and power-sharing deviation remained below 3% and 5%, respectively. Full article

This paper presents an analysis of indoor air quality (IAQ) and occupant perception under different mechanical ventilation operational modes in a university amphitheater. Indoor environmental parameters, including air temperature, relative humidity, indoor air velocity, and CO₂ concentration, were measured in accordance with ISO 7726. Ventilation performance and outdoor air supply requirements were evaluated according to BAS EN 16798-1 and ASHRAE 62.1, while thermal comfort interpretation followed ISO 7730. In parallel, a questionnaire survey was conducted to assess occupants’ perceptions of indoor air quality and its influence on concentration under different ventilation operating conditions. The results showed that CO₂ concentrations occasionally exceeded 1000 ppm during extended occupancy periods but remained below 800 ppm for more than 60% of the measurement time. According to BAS EN 16798-1, the indoor environment was predominantly classified as Category I based on the indoor–outdoor CO₂ concentration difference. Survey responses indicated that most students perceived the indoor air as clean, while 67% reported that IAQ influenced their ability to concentrate. The findings highlight the importance of occupancy-related ventilation control strategies in large educational spaces and demonstrate the potential for balancing indoor air quality and energy efficiency through appropriate ventilation system operation. The presented methodology may support future development of data-driven approaches for optimizing mechanical ventilation performance in university buildings. Full article

This study evaluates the effects of hydrogen enrichment of compressed natural gas (HCNG, CNG) on particle number emissions and particle size distribution in a dual-fuel compression-ignition (CI) engine. The experiments were conducted using a Fiat 1.3 MultiJet engine operated with conventional diesel fuel, diesel–CNG, and diesel–hydrogen-enriched CNG. Measurements were performed over a range of engine speeds, loads, and energy-substitution conditions. The hydrogen volume fraction in the gaseous fuel ranged from 5–10 vol.% to 53 vol.%. Particle size distributions were measured using an ELPI+ impactor. The use of CNG and hydrogen generally reduced soot-particle emissions in the accumulation mode, particularly within the particle-diameter range of approximately 0.03–0.2 µm. However, under some operating conditions, the number of ultrafine particles increased, particularly in the sub-23 nm range. This finding indicates a transition from a particle-formation mechanism dominated by soot formation and agglomeration to one dominated by nucleation and condensation. This phenomenon is associated with suppressed soot-precursor formation, enhanced soot oxidation by OH radicals, and a reduction in the surface area available for the condensation of volatile components. The effect of hydrogen depended on the engine operating point (EOP) and did not always scale linearly with hydrogen concentration. The results confirm that evaluating alternative fuels solely on the basis of particulate mass is insufficient. Particle number, particle size distribution, and the sub-23 nm fraction must also be considered. Full article

The construction sector is a complex industry whose growth and development are closely associated with overall economic expansion and the circular economy. Within this sector, Building Energy Simulation (BES) is widely employed to evaluate and compare the energy performance of proposed office buildings under both baseline conditions and with alternative heating, ventilation, and air-conditioning (HVAC) and domestic hot water (DHW) system configurations. The primary objective of this research was to conduct an energy performance assessment of administrative buildings located in Bratislava, Slovakia. A progressive methodology based on dynamic heat transfer simulation algorithms was applied to evaluate five alternative scenarios (C1–C5). Building performance and heat flow behavior were modeled and analyzed using DesignBuilder software (Version 7). The simulation results revealed that Scenario C5 represents the most effective solution for both administrative building A and administrative building B. From an economic standpoint, Scenario C5 also achieved the lowest energy costs when the DD3 electricity tariff was applied. The DD3 tariff is a dual-rate electricity pricing scheme intended for consumers with higher levels of electricity consumption during off-peak (low-tariff) periods. The findings indicate that a high level of energy sustainability in office buildings can be achieved through the effective implementation of optimized HVAC and DHW systems. Moreover, the integration of energy-efficiency measures contributes to enhanced economic performance by reducing overall energy consumption and associated operating costs. Full article

As offshore wind development moves toward deeper waters, floating offshore wind turbines have become essential for carbon-neutral energy systems. This study experimentally investigates the hydrodynamic coefficients of typical column–heave-plate components under forced oscillations, focusing on the influence of pitch-induced inclination. A circular column without a heave plate and a circular column equipped with a hexagonal heave plate were tested under heave and surge motions with varying periods, amplitudes, and static inclination angles. The static inclinations were used to represent the attitude variation of platform components during large-amplitude pitch responses. Added mass and damping coefficients were identified using the least squares method. The results show that for the heave-plate-equipped column, increasing the inclination from 0° to 5° and 10° reduced the nondimensional heave added mass by approximately 4.3% and 5.9%, respectively, and reduced the nondimensional heave damping by approximately 7.1% and 6.8%. The corresponding reductions in surge added mass were approximately 5.3% and 10.5%, whereas the reductions in surge damping reached approximately 8.2% and 16.4%, indicating that the surge damping is most sensitive to static inclination. These variations may be associated with the altered geometric projection and disturbed flow symmetry of the inclined component, which may affect the attached-fluid volume and energy-dissipation process during forced oscillation. Future studies should further verify the corresponding local separation and vortex-formation mechanisms through detailed flow-field measurements, PIV, or CFD. Full article

The mechanical characteristics and the rupture behavior of dry paper and papers immersed in pure water or a carboxymethyl cellulose (CMC) aqueous solution were investigated by measuring the shape changes due to the immersion and by uniaxial tensile tests. The weight changes and dimensional changes for these samples due to the immersion were evaluated by the gravimetric method and image analysis, respectively. The absorption ratio of the paper was 2.3 for pure water, and it increased up to 2.7 with the CMC concentration. A deformation of 5% at maximum was observed in the direction perpendicular to the fiber orientation due to the absorption. All the samples demonstrated similar stress–strain curves in the regions of linear viscoelasticity and plastic deformation. The peak stress, Young’s modulus, and strain energy density of CMC wet paper showed lower values than those of water wet paper, while the peak strain was the same for both samples. Similar behavior was found in the cross direction, although the difference was not significant. These results strongly indicate that the penetration and adsorption of CMC molecules lead to a large expansion, resulting in the disentanglement of paper fibers and a significant reduction in the mechanical properties due to the strong fluid lubrication effect. Full article

In this study, laser powder bed fusion (PBF-LB) 022Cr17Ni12Mo2 steel plates with dimensions of 50 mm × 50 mm × 2 mm were fabricated using a laser power of 206 W, a scanning speed of 900 mm/s, a hatch spacing of 90 μm, a layer thickness of 30 μm, and an interlayer scanning rotation of 67°. The specimens were then subjected to solution treatment at 900–1100 °C for 30 min and at 950 °C for 30–120 min. Unlike previous ultrasonic studies on additively manufactured metals, which mainly focused on defect detection, elastic-constant characterization, or residual stress evaluation, this work investigates whether solution-treatment-induced changes in grain size and dislocation density can be quantitatively reflected by laser-ultrasonic attenuation and further correlated with yield strength. Laser ultrasonic nondestructive testing using a 1064 nm pulsed laser with a pulse width of 8 ns and a pulse energy of 500 mJ was combined with metallographic observation, EBSD characterization, XRD analysis, tensile testing, and microhardness measurement. The results show that the solution-treated samples retained a single-phase γ-austenitic structure, while microstructural recovery, weakening of PBF-LB-induced cellular substructures, and partial annihilation of cell-wall dislocations led to a reduction in KAM-derived dislocation density from 2.04 × 10¹⁴ m⁻² to 1.45 × 10¹⁴ m⁻² and a decrease in yield strength from 466.9 MPa to 407.4 MPa. Within the present dataset, the EBSD-equivalent grain size showed an apparent positive correlation with ultrasonic attenuation, while the KAM-derived dislocation density showed an empirical negative correlation with ultrasonic attenuation. However, ultrasonic attenuation should be interpreted as a combined microstructure-sensitive response rather than as a response controlled only by EBSD-equivalent grain size or dislocation density. Based on the empirical correlations among ultrasonic attenuation, EBSD-equivalent grain size, KAM-derived dislocation density, and yield strength, a preliminary attenuation-based calibration model was established for the present solution-treated samples. The model should be regarded as an in-sample empirical calibration within the present experimental range rather than a general Hall–Petch-based predictive model. The model showed good in-sample fitting performance, with (R²) values higher than 0.85 and a maximum in-sample fitting error of 3.85%. However, because the model was established and assessed using the same eight solution-treatment conditions, it should be regarded as a preliminary calibration model within the present experimental range rather than a general predictive model. This study demonstrates the potential of laser ultrasonic attenuation for non-contact evaluation of microstructural and mechanical-property variations in solution-treated PBF-LB 022Cr17Ni12Mo2 steel. Full article

Wearable sweat biosensors require electrode materials with high surface area, conductivity and mechanical compliance, yet chemically polymerized polyaniline forms dense, low-surface-area films with limited flexibility. In this work, flexible free-standing nanofiber mats were fabricated by coaxial electrospinning, using a sulfuric-acid-doped polyacrylonitrile/polyaniline (PAN/PANI) core and a shell containing graphene oxide nanoscrolls (GONS) at 1 and 3 wt%, followed by gold nanoparticle and ferrocene incorporation, glucose oxidase (GOx) immobilization and a Nafion coating. Scanning electron microscopy showed uniform bead-free fibers with an interconnected pore network and an apparent image-derived porosity of approximately 40%. Energy-dispersive X-ray spectroscopy confirmed the uniform distribution of carbon, oxygen, nitrogen and sulfur across the matrix. Fourier-transform infrared spectroscopy retained the nitrile band at 2243 cm⁻¹ and the quinoid and benzenoid bands at 1547 and 1476 cm⁻¹, while amide bands at 1730 and 1641 cm⁻¹ confirmed retention of protein from enzymes. X-ray diffraction gave crystallinities of 76.6% for GONS and 60% for the pure PANI. Four-point probe measurements showed conductivity increasing from 0.0481 S/cm to 1 wt% GONS to 0.0595 S/cm for the 3 wt% mat with additives. These material and structural characterizations establish a promising foundation for future electrochemical validation and sensor development. Full article