The knowledge of the acoustic impedance of a material allows for the calculation of its acoustic absorption. Impedance can also be linked to structural and physical proprieties of materials. However, while the impedance of pavement samples in laboratory conditions can usually be measured with high accuracy using devices such as the impedance tube, complete in-situ evaluation results are less accurate than the laboratory results and is so time consuming that a full scale implementation of in-situ evaluations is practically impossible. Such a system could provide information on the homogeneity and the correct laying of an installation, which is proven to be directly linked to its acoustic emission properties. The present work studies the development of a measurement instrument which can be fastened through holding elements to a moving laboratory (i.e., a vehicle). This device overcomes the issues that afflict traditional in-situ measurements, such as the impossibility to perform a continuous spatial characterization of a given pavement in order to yield a direct evaluation of the surface’s quality. The instrumentation has been uncoupled from the vehicle’s frame with a system including a Proportional Integral Derivative (PID) controller, studied to maintain the system at a fixed distance from the ground and to reduce damping. The stabilization of this device and the measurement system itself are evaluated and compared to the traditional one.

Noise in hospital wards adversely affects the physiological processes of both patients and staff and it is a potential risk for communication breakdowns and errors, causing discomfort and problems regarding the healing of patients, as well as stress, fatigue, and annoyance for staff. Several noise sources are present in the wards, such as HVAC systems, alarms, paging, speech, calls, diagnostic equipment, medical devices, and so forth. This paper describes two surveys carried out at an Italian hospital in Rome to investigate the noise in some wards and to collect self-reported assessments from staff about their working environments, even if such assessments were not required for occupational noise exposure evaluation. Self-reported staff evaluations of the working environment quality and the effects of noise on their performances should be investigated. For this purpose, in this study, questionnaires were designed and submitted to staff members. In addition, noise measurements were taken from short-, medium-, and long-term audio recordings processed to determine psychoacoustic parameters, e.g., loudness, sharpness, roughness, and fluctuation strength. Their applications in enclosed spaces can provide additional information on some features of the noise observed in hospital wards, which may influence the perceptions and relevant extra-auditory effects. Even though the results cannot be generalized, they encourage the development of a methodology for noise surveys in hospital wards, including noise measurements and “ad hoc” questionnaires to collect self-reported reactions from exposed staff members.

On the contrary the infrasonic region of the spectrum is still under investigation. The first study on the presence of the infrasound in air go back to the end of the 19th century and its effects on the human beings have been investigated since the World War II. In this paper is presented an overview of the technologies used to detect infrasound in different research fields, pointing out their pros and cons. System specification for urban area infrasound noise monitoring require transportability, robustness, reduced dimensions to avoid large space occupation and low cost devices for a distributed monitoring.

The present work explores the modelling and design of Interface Acoustic Wave (IAW)-based delay lines in SiO₂/ZnO (4 µm)/SU-8/SiO₂ multilayer stacks and demonstrates that, by properly tailoring the acoustic wavelength and the SU-8 layer thickness, IAW delay lines can achieve performances comparable to, and in some cases superior to, those of conventional Surface Acoustic Wave (SAW) delay lines based on SiO₂/ZnO (4 µm) structures. In particular, the proposed devices exhibited untuned insertion losses down to 12 dB, propagation losses as low as 0.052 dB/λ, and electromechanical coupling coefficients K² approaching 4%, exceeding those calculated for the corresponding SAW devices. The obtained results support the feasibility of compact, high-performance, and potentially packageless acoustic-wave devices for future telecommunications and sensing applications, especially in harsh or contamination-prone environments.