This study presents a compact, lightweight, and reconfigurable acoustic metatile for sound mitigation applications. The metatile prototype is designed based on a circular maze-like acoustic metastructure, which utilizes a space-coiling technique for enhanced acoustic performance in low-to-mid frequencies. The proposed labyrinthine acoustic metadisk structure comprises a central hollow front face sheet and two coiling-up backing cavities. Experimental results show that the metadisk has high absorption peaks of 0.81 and 0.75 at 574 and 1436 Hz, respectively, and exhibits high sound transmission loss (STL) values ( ≥25 dB) in separate wide frequency bands between 100–580 Hz and 820–1600 Hz. Based on the metadisk samples, metatiles are constructed, which are 30.5 × 30.5 cm 2 in size. The acoustic performance of these metatiles is investigated in two distinct scenarios. Two prototypes of the acoustic metatile are presented: the metacage and the metapanel. The metacage is a cubical box-shaped structure constructed using five metatiles, which showed a wideband insertion loss of ≥10 dB in 200–16 000 Hz and ≥20 dB over 400–5000 Hz. On the other hand, the metapanel is constructed using nine metatiles, which exhibited STL values of >20 dB over 125–5000 Hz and had a sound transmission class rating of 34. The study highlights the potential of circular maze-like space-coiling-based acoustic disk metastructures to be reconfigured into metatiles and assembled into a metacage or metapanel for practical sound mitigation applications.
Besides its clinical applications, various researchers have shown that EMG can be utilised in areas such as computer human interface and in developing intelligent prosthetic devices. The paper presents results from a preliminary study. The work describes the outcome in using an artificial neural network (ANN) to recognise and classify human speech based on EMG. The EMG signals were acquired from three articulatory facial muscles. Three subjects were selected and participated in the experiments. Preliminarily, five English vowels were used as recognition variables. The root mean square (RMS) values of the EMG signals were estimated and used as a set of features to feed the ANN. The findings indicate that such a system may have the capacity to recognise and classify speech signals with an accuracy of up to 88%.
Vacuum cleaners are one of the most widely used household appliances associated with unpleasant noises. Previous studies have indicated the severity of loud vacuum cleaner noise and its impact on the users nearby. The standalone quantified measurements of the generated noise are not sufficient for properly characterizing vacuum cleaners. Human perception should also be included for a better assessment of the quality of sound. A hybrid approach such as psychoacoustics analysis, which comprises subjective and objective evaluations of sounds, has recently been widely used. This paper focuses on the experimental assessment of vacuum cleaner noise and evaluates their psychoacoustical matrices. Three vacuum cleaners with different specifications have been selected as test candidates, and their sound qualities have been analyzed. Statistical analysis, ANOVA, has been performed in order to investigate the effectiveness of individual psychoacoustic metrics.
In the past decade, the term 'global aging' has gained much attention among researchers, policymakers, civil societies, and governments worldwide. The continuous decline in fertility rates and increased life expectancy have resulted in an ongoing demographic transition where the share of adults aged 65 or older is increasing and outnumbering children younger than five years. In the United States and other developed countries, this rapid demographic transition is expected to continue to strain the existing health infrastructure as it becomes increasingly challenging to ensure healthy living environments for older adults. The ten questions and answers in this paper have been prepared by experts from gerontology, geriatrics, architectural engineering, and senior living operations to inform and characterize the current continuum of living environments and communities available to older adults. They also identify the common elements that influence the environmental needs of older adults and highlight factors (such as technical assistance, health equity gaps, and caregiver workforce development) that challenge the future of smart and healthy built environments for older adults. A special focus has been placed on contextualizing indoor environmental quality (IEQ) elements and smart building technologies for older individuals, caregivers, and their various requirements (perhaps in their own homes and communities). Together, these viewpoints create a new paradigm to assist in designing and managing intelligent, healthy built environments that respond to human demands. Although this paper focuses on factors in the United States, others can benefit from the framework incubated upon these experiences, making this effort relevant towards addressing global opportunities in environments for older adults.
One of the central challenges in cardiac tissue engineering is the control of the assembly and organization of functional cardiac tissue. Maintenance of a three-dimensional tissue architecture is key to myocardial function in vivo, and a variety of studies hint that provision of topological cues within scaffolds can facilitate the engineering of functional myocardial tissue by promoting this architecture. To explore this possibility in an isolated and well-defined fashion, we have designed scaffolds of polydimethylsiloxane (PDMS) with microtopographic pillars ("micropegs") to provide cells with defined structures with which to interact in three dimensions. We show that these surfaces permit HL-1 cardiomyocytes to grow, form myofibrillar structures and cell-cell adhesions, and beat spontaneously. Additionally, the cells and their nuclei interact with the full length of the micropegs, indicating that the micropegs promote a three-dimensional cytoarchitecture in the context of a two-dimensional scaffold. We also show that the number of cells interacting with a micropeg can be controlled by manipulating incubation time, micropeg spatial arrangement, or micropeg diameter. Western blots reveal that the expression of the junctional markers N-cadherin and connexin 43 is upregulated in the presence of specific arrangements of micropegs, suggesting that micropegs can enhance cardiomyocyte function. Together, these data show that microtopography can be used to provide three-dimensional adhesion and control the assembly of functional cardiac tissue on a two-dimensional surface.
'%3e%3ccircle r='20' fill='%23008'/%3e%3ccircle r='17.5' fill='%23fff'/%3e%3ccircle r='3.5' fill='%23008'/%3e%3cg id='d'%3e%3cg id='c'%3e%3cg id='b'%3e%3cg id='a' fill='%23008'%3e%3ccircle r='.875' transform='rotate(7.5 -8.75 133.5)'/%3e%3cpath d='M0 17.5.6 7 0 2l-.6 5L0 17.5z'/%3e%3c/g%3e%3cuse xlink:href='%23a' transform='rotate(15)'/%3e%3c/g%3e%3cuse xlink:href='%23b' transform='rotate(30)'/%3e%3c/g%3e%3cuse xlink:href='%23c' transform='rotate(60)'/%3e%3c/g%3e%3cuse xlink:href='%23d' transform='rotate(120)'/%3e%3cuse xlink:href='%23d' transform='rotate(-120)'/%3e%3c/g%3e%3c/svg%3e)
'/%3e%3cuse xlink:href='%23a' transform='translate(288.889 -214.211)'/%3e%3cuse xlink:href='%23a' transform='translate(108 342.749)'/%3e%3cuse xlink:href='%23a' transform='translate(469.189 342.749)'/%3e%3c/svg%3e)
