Rayleigh waves in air saturated axisymmetrical soft porous media

International audienc

Methods for the characterization of sound packages containing visco-elastic and anisotropic porous materials

International audienceA wide range of commercial applications, in both building acoustics as well as automotive industry, can be found for sound packages containing poro-elastic materials. Accurate material characterization is vital for the use of these multilayered systems due to the increasing demands in acoustic comfort and legislation. There is however a distressing lack in raw, accurate material data and measurement methods concerning the characterization of these materials. Especially the effect of anisotropy and visco-elasticity on the acoustic properties of multilayered systems remains barely understood. Measuring and modeling methods for the characterization of these materials at an acoustically interesting frequency range will be presented. The experimental technique for the determination of the elastic properties is based upon the excitation of waveguides in anisotropic and visco-elastic porous materials. The other parameters of the Biot-Allard model are determined using the classical methods. Results concerning surface wave phase velocities show that anisotropy and visco-elasticity influence the acoustical properties of porous media which are calculated using a transfer matrix approach

Lyme borreliosis in Belgium: a cost-of-illness analysis

Background. Lyme borreliosis (LB) is the most common tick-borne disease in Europe and North America, yet its economic burden remains largely unknown. This study aimed to estimate the economic cost associated with the different clinical manifestations of LB in&nbsp;Belgium. Methods. An incidence approach and societal perspective were used to estimate the total cost-of-illness for LB in Belgium. Costs were calculated for patients with erythema migrans (EM) or disseminated/late LB, including patients who developed post-treatment Lyme disease syndrome (PTLDS). Direct medical, direct non-medical (transportation &amp; paid help) and indirect non-medical costs (productivity losses) were included in the analysis. Ambulatory cost data were collected through a prospective cohort study from June 2016 to March 2020, in which patients with LB were followed up 6 to 12&nbsp;months after diagnosis. Hospitalization costs were retrieved from the Minimal Clinical Data registry, a mandatory registry for all Belgian hospitals, linked to the Minimal Financial Data registry. Costs were expressed in 2019&nbsp;euros. Results. The total annual cost associated with clinical manifestations of LB in Belgium was estimated at €5.59 million (95% UI 3.82–7.98). Of these, €3.44 million (95% UI 2.05–5.48) or 62% was related to disseminated/late LB diagnoses and €2.15 million (95% UI 1.30–3.26) to EM. In general, direct medical costs and productivity losses accounted for 49.8% and 46.4% of the total costs, respectively, while direct non-medical costs accounted for only 3.8%. The estimated mean costs were €193 per EM patient and €5,148 per disseminated/late LB patient. While patients with PTLDS seemed to have somewhat higher costs compared to patients without PTLDS, the number of patients was too small to have representative&nbsp;estimates. Conclusions. We estimate the total annual direct medical costs, direct non-medical and indirect non-medical costs associated with LB to exceed €5.5 million per year, almost evenly distributed between EM (40%) and disseminated/late LB (60%). EM costs 26 times less per patient but occurs also 16 times more frequently than disseminated/late LB. The cost burden remains limited by comparison to other infectious diseases due to the relative lower&nbsp;incidence.</p

Phytoremediation of metal contaminated soils: data from field experiments

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