The Transmission of an Acoustic Wave Through a Composite Plate with Energy Dissipation in a Material Taken into Account Based on Three-Dimensional Equations of Elasticity Theory

© Springer Nature Switzerland AG 2020. The problem of a plane monoharmonic sound wave passage through a thin composite rectangular plate hinged in the opening of an absolutely stiff dividing wall has been considered on the basis of two-dimensional in spatial coordinates motion equations. These equations have been constructed by the reduction of three-dimensional equations on the basis of the discrete layered model of a multilayer plate deformation at small displacements and deformations with account of the internal damping of layers according to the Kelvin–Voight model. Behavior of acoustic media has been described by the classical wave equations based on the model of an ideal compressible fluid. The exact analytical solutions of the formulated problem have been constructed. The dependence of sound insulation properties and parameters of the stress-strain state of a composite plate reinforced with carbon fiber textile on the incident sound wave frequency was studied. It is shown that under high-frequency acoustic impact, the deformation mechanics of the structures made of fiber reinforced composite must be described by refined equations of motion as they have a high degree of accuracy and intensionality since the formation of the stress-strain state in them is almost three-dimensional with components of the same order

The psychrometric control of house dust mites: a pilot study

This paper describes a pilot intervention study on the effectiveness of house dust mite allergen avoidance for 12 asthmatic children (two being controls). In addition to mite allergen removal, the study included tailored advice aimed at reducing mite population growth via changes in moisture production, heating and ventilation habits. This paper focuses on the effects of this advice on household behaviour, hygrothermal conditions and mite populations. The efficacy of monitoring and modelling techniques is also discussed. The study highlighted a number of interrelated confounding factors which have to be addressed in future similar larger scale studies, but the results are promising with regards to the effectiveness of such studies. Practical application: This study suggests that in temperate climates tailored advice on moisture production, heating and ventilation habits can lead to valuable changes in hygrothermal conditions, which in turn can result in reduced mite populations. However, pre-existing adverse building conditions may hinder such changes, and the effectiveness of tailored advice and of hygrothermal modifications is often difficult to assess. It is therefore recommended that any similar larger intervention study measures ventilation rates and adequately controls for a number of confounding variables – including the effect of changes in outdoor conditions and of the removal of existing mite populations. In this respect, hygrothermal population models can play a very useful role in the assessment of study effectiveness