Search Results (79)

The COVID-19 pandemic’s rapid shift to working from home has fundamentally challenged residential acoustic design, which traditionally prioritises rest and relaxation rather than sustained concentration. However, a clear gap exists in understanding how acoustic needs and the subjective evaluation of soundscape appropriateness (SA) differ between these conflicting activities within the same domestic space. Addressing this gap, this study reveals critical differences in how people experience and evaluate home soundscapes during work versus relaxation activities in the same residential spaces. Through an online survey of 247 Chinese participants during lockdown, we assessed soundscape perception attributes, the perceived saliencies of various sound types, and soundscape appropriateness (SA) ratings while working and relaxing at home. Our findings demonstrate that working at home creates a more demanding acoustic context: participants perceived indoor soundscapes as significantly less comfortable and less full of content when working compared to relaxing (p < 0.001), with natural sounds becoming less noticeable (−13.3%) and distracting household sounds more prominent (+7.5%). Structural equation modelling revealed distinct influence mechanisms: while comfort significantly mediates SA enhancement in both activities, the effect is stronger during relaxation (R² = 0.18). Critically, outdoor man-made noise, building-service noise, and neighbour sounds all negatively impact SA during work, with neighbour sounds showing the largest detrimental effect (total effect size = −0.17), whereas only neighbour sounds and outdoor man-made noise significantly disrupt relaxation activities. Additionally, natural sounds act as a positive factor during relaxation. These results expose a fundamental mismatch: existing residential acoustic environments, designed primarily for rest, fail to support the cognitive demands of work activities. This study provides evidence-based insights for acoustic design interventions, emphasising the need for activity-specific soundscape considerations in residential spaces. As hybrid work arrangements become the norm post-pandemic, our findings highlight the urgency of reimagining residential acoustic design to accommodate both focused work and restorative relaxation within the same home. Full article

Although Mercury Intrusion Porosimetry (MIP) and Nuclear Magnetic Resonance (NMR) are widely used for pore characterization, their effectiveness is fundamentally constrained by theoretical limitations. This study investigated the pore structure characteristics of coal-bearing sandstones from the northeastern Ordos Basin using an integrated approach combining experimental measurements and model-based inversion. The experimental measurements comprised a stress-dependent acoustic velocity test (P- and S-wave velocities), X-ray diffraction (XRD) mineralogical analysis, and NMR relaxation T₂ spectra characterization. For model-based inversion, we developed an improved Mori-Tanaka (M-T) theoretical framework incorporating stress-sensitive pore geometry parameters and dual-porosity (stiff/soft) microstructure representation. Systematic analysis revealed four key findings: (1) excellent agreement between model-inverted and NMR-derived total porosity, with a maximum absolute error of 1.09%; (2) strong correlation between soft porosity and the third peak of T₂ relaxation spectra; (3) stiff porosity governed by brittle mineral content (quartz and calcite), while soft porosity showing significant correlation with clay mineral abundance and Poisson’s ratio; and (4) markedly lower elastic moduli (28.78%–51.85%) in Zhiluo Formation sandstone compared to Yan’an Formation equivalents, resulting from differential diagenetic alteration despite comparable depositional settings. The proposed methodology advances conventional NMR analysis by simultaneously quantifying both pore geometry parameters (e.g., aspect ratios) and the stiff-to-soft pore distribution spectra. This established framework provides a robust characterization of the pore architecture in Jurassic sandstones, yielding deeper insights into sandstone pore evolution within the Ordos Basin. These findings provide actionable insights for water hazard mitigation and geological CO₂ storage practices. Full article

This study explores the impact of soundscapes on the emotional and academic experiences of preservice teachers enrolled in music education courses within an elementary education degree program. It focuses on the framework of critical music education and future teachers’ reflections on soundscapes, emphasizing the importance of fostering awareness of the acoustic environment. The study uses a mixed-methods approach, including a quasi-experimental design and group discussions, to assess the emotional and cognitive effects of listening to natural versus urban soundscapes among preservice teachers (n = 89). The results indicate that listening to natural soundscapes significantly increases positive emotions and reduces negative emotions, while urban soundscapes have the opposite effect. Group discussions revealed that university campus soundscapes, often dominated by traffic and construction noise, negatively impacts students’ socialization, relaxation, and concentration, potentially affecting their academic performance. The study suggests incorporating soundscape awareness and critical listening into music education programs to foster both environmental and social awareness among students and to support the development of critical consciousness in future educators and citizens. Full article

The accurate assessment of muscle morphology and function is crucial for medical diagnostics, rehabilitation, and biomechanical research. This study presents a novel methodology for constructing volumetric models of forearm muscles based on three-dimensional ultrasound imaging integrated with a robotic system to ensure precise probe positioning and controlled pressure application. The proposed ultrasound scanning approach combined with a collaborative six-degrees-of-freedom robotic manipulator enabled reproducible and high-resolution imaging of muscle structures in both relaxed and contracted states. A custom-built phantom, acoustically similar to biological tissues, was developed to validate the method. The cross-sectional area of the muscles and the coordinates of the center of mass of the sections, as well as the volume and center of gravity of each muscle, were calculated for each cross-section of the reconstructed forearm muscle models at contraction. The method’s feasibility was confirmed by comparing the reconstructed volumes with anatomical data and phantom measurements. This study highlights the advantages of robotic-assisted ultrasound imaging for non-invasive muscle assessment and suggests its potential applications in neuromuscular diagnostics, prosthetics design, and rehabilitation monitoring. Full article

We studied relaxation processes in heavily doped two-dimensional Dirac systems associated with electron scattering by acoustic and optical phonons and by static disorder. The frequency dependence of the real and imaginary parts of the relaxation function is calculated for different temperatures. The two-component low-frequency dynamical conductivity is found to be strongly dependent on temperature. At low temperatures, the imaginary part of the zero-frequency relaxation function and the DC resistivity are characterized by the scaling law $a{T}^x$ with the exponent x between 2.5 and 3. Full article

The user’s experience is critical in spatial design, particularly in outdoor spaces like university campuses, where the physical environment significantly influences students’ relaxation and stress relief. This study investigates the combined impact of thermal, luminous, and auditory environments on students’ perceptions within recreational areas at Bordj Bou Arreridj University Campus. A mixed-method approach combined field surveys and on-site measurements across eleven locations within three distinct spatial configurations. The findings from this study indicate that the auditory environment had the most substantial influence on overall perceptions, surpassing luminous and thermal factors. The open courtyard (Area 1) was perceived as less comfortable due to excessive heat and noise exposure. The shaded zone (Area 2) was identified as the most vulnerable, experiencing significant thermal stress and noise disturbances. In contrast, the secluded patio (Area 3) achieved the highest comfort rating and was perceived as the most cheerful and suitable space. Correlation analysis revealed significant interrelationships between physical and perceptual dimensions, highlighting the critical role of factors such as wind velocity, sky view factor, and illuminance in shaping thermal, luminous, and acoustic perceptions. A fuzzy logic model was developed to predict user perceptions of comfort, suitability, and mood based on measured environmental parameters to address the complexity of multisensory interactions. This study highlights the importance of integrating multisensory evaluations into spatial design to optimize the quality of outdoor environments. Full article

We report on the dynamic interactions between β-cyclodextrin (β-CD) and each one of the two enantiomers of asparagine (d-Asp, l-Asp). Molecular docking methodologies were applied to elucidate the formation of the β-CD—d-Asp and β-CD—l-Asp inclusion complexes. Ultrasonic relaxation spectra revealed a single relaxation process in the frequency range studied that is attributed to the complexation between β-CD and asparagine enantiomers. Kinetic parameters and thermodynamic properties for each system were determined directly from the concentration- and temperature-dependent acoustic measurements, respectively. Both β-CD—d-Asp and β-CD—l-Asp systems revealed subtle differences in their thermodynamic and kinetic properties. The infrared absorption spectra of the host molecule, the guest enantiomers, and both inclusion complexes were recorded to verify and further elucidate the complexation mechanism. DFT methodologies were performed to calculate the theoretical IR spectra of the inclusion complexes and compared with the corresponding experimental spectra. The close resemblance between the experimental and theoretically predicted IR spectra is supportive of the formation of inclusion complexes. The encapsulation of asparagine enantiomers in β-cyclodextrin enables not only applications in drug delivery but also the detection and separation of chimeric molecules. Full article

Corneal biomechanical properties are closely related to the cornea’s physiological and pathological conditions, primarily determined by the stromal layer. However, little is known about the influence of corneal cell interaction on the viscoelasticity of the stromal extracellular matrix (ECM). In this study, collagen-based hydrogels incorporated with keratocytes were reconstructed as corneal stromal models. Air-pulse optical coherence elastography (OCE) was used to characterize the viscoelastic properties of the corneal models. Plate compression, ramp–hold relaxation testing was performed on the initial corneal models. The findings demonstrated that the elastic modulus increased 5.27, 2.65 and 1.42 kPa, and viscosity increased 0.22, 0.06 and 0.09 Pa·s in the stromal models with initial collagen concentrations of 3, 5, and 7 mg/mL over 7 days. The elastic modulus and viscosity exhibited high correlation coefficients between air-pulse OCE and ramp–hold relaxation testing, with 92.25% and 98.67%, respectively. This study enhances the understanding of the influence of cell–matrix interactions on the corneal viscoelastic properties and validates air-pulse OCE as an accurate method for the mechanical characterization of tissue-engineered materials. Full article

As important recreational spaces for urban residents, urban microgreen parks enhance the urban living environment and alleviate psychological pressure on residents. The visual, auditory, and olfactory senses are crucial forms of perception in human interaction with nature, and the sustainable perceptual design of miniature green parks under their interaction has become a recent research hotspot. This study aimed to investigate the effects of the visual, acoustic, and olfactory environments (e.g., aromatic green vegetation) on human perception in miniature green parks. Participants were evenly divided into eight groups, including single-sensory groups, multi-sensory interaction groups, and a control group. Eye-tracking technology, blood pressure monitoring, and the Semantic Differential (SD) scales and Profile of Mood State (POMS) were used to assess the effectiveness of physical and mental perception recovery in each group. The results revealed that in an urban microgreen space environment with relatively low ambient noise, visual–auditory, visual–olfactory, and visual–auditory–olfactory interactive stimuli were more effective in promoting the recovery of visual attention than single visual stimuli. Additionally, visual–auditory–olfactory interactive stimuli were able to optimize the quality of spatial perception by using positive sensory inputs to effectively mask negative experiences. Simultaneously, environments with a high proportion of natural sounds had the strongest stimuli, and in the visual–auditory group, systolic blood pressure at S7 and heart rate at S9 significantly decreased (p < 0.05), with reductions of 18.60 mmHg and 20.15 BPM, respectively. Aromatic olfactory sources were more effective in promoting physical and mental relaxation compared to other olfactory sources, with systolic blood pressure reductions of 24.40 mmHg (p < 0.01) for marigolds, 23.35 mmHg (p < 0.01) for small-leaved boxwood, and 27.25 mmHg (p < 0.05) for camphor trees. Specific auditory and olfactory conditions could guide visual focus, such as birdsong directing attention to trees, insect sounds drawing attention to herbaceous plants, floral scents attracting focus to flowers, and leaf scents prompting observation of a wider range of natural vegetation. In summary, significant differences exist between single-sensory experiences and multi-sensory modes of spatial perception and interaction in urban microgreen parks. Compared to a silent and odorless environment, the integration of acoustic and olfactory elements broadened the scope of visual attention, and In the visual–auditory–olfactory interactive perception, the combination of natural sounds and aromatic camphor tree scents had the best effect on attention recovery, thereby improving the quality of spatial perception in urban microgreen parks. Full article

We measured the temporal voltage response of NbTi superconducting filaments with varied nanoscale thicknesses to step current pulses that induce non-equilibrium superconducting states governed by a hot spot mechanism. Such detected voltage emerges after a delay time $t_d$, which is intimately connected to the gap relaxation and heat escape times. By employing time-dependent Ginzburg–Landau theory to link the delay time to the applied current, we determined that the gap relaxation time depends linearly on film thickness, aligning with the acoustic mismatch theory for phonon transmission at the superconductor–substrate interface. We thereby find a gap relaxation time of 104 ps per nm of thickness for NbTi films on polished sapphire. We further show that interfacial interaction with the substrate significantly impacts the gap relaxation time, with observed values of 9 ns on Si${\mathrm{O}}_x$, 6.8 ns on fused silica, and 5.2 ns on sapphire for a 50 nm thick NbTi strip at $T=5.75$ K. These insights are valuable for optimizing superconducting sensing technologies, particularly the single-photon detectors that operate in the transient regime of nanothin superconducting bridges and filaments. Full article

In the present investigations, the density, refractive index and speed of sound for pure organic solvents and binary liquid mixtures of 3,4,4′-Trichlorodiphenylurea between (293.15 and 323.15) K temperatures have been measured up to the solubility limit. From these experimental results, the acoustic impedance, the isentropic compressibility coefficient, the space-filling factor, the specific refraction, the relaxation strength, the intermolecular free length, the surface tension, the solubility and the solvation number of triclocarban in six organic solvents, namely ethyl alcohol, n-Propyl alcohol, n-Butyl alcohol, Tetrahydrofuran, N,N-Dimethylformamide and N,N-Dimethylacetamide have been computed. The studied acoustic and optical parameters and surface tension behavior versus temperature in pure solvents and binary mixtures were useful in understanding the nature and the extent of interaction between the solute and solvent molecules. The results also show the presence of higher degree of interaction between triclocarban and nitrogen-containing solvents in comparison with other solvents. The distribution of triclocarban in water/organic solvent mixtures is frequently encountered in wastewater treatment plants. Full article

An analysis of the processes of plastic deformation and acoustic relaxation in a high-entropy alloy, Al_0.5CoCrCuFeNi, was carried out. The following were established: dominant dislocation defects; types of barriers that prevent the movement of dislocations; mechanisms of thermally activated movement of various elements of dislocation lines through barriers at room and low temperatures. Based on modern dislocation theory, quantitative estimates were obtained for the most important characteristics of dislocations and their interaction with barriers. Full article

Relaxing the temporal constancy constraint on coupling constants in an expanding universe results in Friedmann equations containing terms that may be interpreted as dark energy and dark matter. When tired light (TL) was considered to complement the redshift due to the expanding universe, the resulting covarying coupling constants (CCC+TL) model not only fit the Type Ia supernovae data as precisely as the ΛCDM model, but also resolved concerns about the angular size of cosmic dawn galaxies observed by the James Webb Space Telescope. The model was recently shown to be compliant with the baryon acoustic oscillation features in the galaxy distribution and the cosmic microwave background (CMB). This paper demonstrates that dark energy and dark matter of the standard ΛCDM model are not arbitrary but can be derived from the CCC approach based on Dirac’s 1937 hypothesis. The energy densities associated with dark matter and dark energy turn out to be about the same in the ΛCDM and the CCC+TL models. However, the critical density in the new model can only account for the baryonic matter in the universe, raising concerns about how to account for observations requiring dark matter. We therefore analyze some key parameters of structure formation and show how they are affected in the absence of dark matter in the CCC+TL scenario. It requires reconsidering alternatives to dark matter to explain observations on gravitationally bound structures. Incidentally, since the CCC models inherently have no dark energy, it has no coincidence problem. The model’s consistency with the CMB power spectrum, BBN element abundances, and other critical observations is yet to be established. Full article

Recent advancements in marine technology have highlighted the urgent need for enhanced underwater acoustic applications, from sonar detection to communication and noise cancellation, driving the pursuit of innovative transducer technologies. In this paper, a new underwater thermoacoustic (TA) transducer made from carbon nanotube (CNT) sponge is designed to achieve wide bandwidth, high energy conversion efficiency, simple structure, good transient response, and stable sound response, utilizing the TA effect through electro-thermal modulation. The transducer has potential application in underwater acoustic communication. An electro-thermal-acoustic coupled simulation for the open model, sandwich model, and encapsulated model is presented to analyze the transient behaviors of CNT sponge TA transducers in liquid environments. The effects of key design parameters on the acoustic performances of both systems are revealed. The results demonstrate that a short pulse excitation with a low duty cycle could greatly improve the heat dissipation of the encapsulated transducer, especially when the thermoacoustic response time becomes comparable to thermal relaxation time. Full article

The purpose of this study is to use acoustic emission (AE) technology to explore the changes in the interface and mechanical properties of GF/VER composite materials after being treated with NaOH and to analyze the optimal modification conditions and damage propagation process. The results showed that the GF surface became rougher, and the number of reactive groups increased after treating the GF with a NaOH solution. This treatment enhanced the interfacial adhesion between the GF and VER, which increased the interfacial shear strength by 25.31% for monofilament draw specimens and 27.48% for fiber bundle draw specimens compared to those before the GF was modified. When the modification conditions were a NaOH solution concentration of 2 mol/L and a treatment time of 48 h, the flexural strength of the GF/VER composites reached a peak value of 346.72 MPa, which was enhanced by 20.96% compared with before the GF was modified. The process of damage fracture can be classified into six types: matrix cracking, interface debonding, fiber pullout, fiber relaxation, matrix delamination, and fiber breakage, and the frequency ranges of these failure mechanisms are 0~100 kHz, 100~250 kHz, 250~380 kHz, 380~450 kHz, 450~600 kHz, and 600 kHz and above, respectively. This paper elucidates the fracture process of GF/VER composites in three-point bending. It establishes the relationship between the AE signal and the interfacial and force properties of GF/VER composites, realizing the classification of the damage process and characterizing the mechanism. The frequency ranges of damage types and failure mechanisms found in this study offer important guidance for the design and improvement of composite materials. These results are of great significance for enhancing the interfacial properties of composites, assessing the damage and fracture behaviors, and implementing health monitoring. Full article