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Fungal spore organic aerosol emissions have been recognised as a significant source of particulate matter as PM10 ; however, they are not widely considered in current air quality models. In this work, we have implemented the parameterisation of fungal spore organic aerosol (OA) emissions introduced by Heald and Spracklen (2009) (H&S) and further modified by Hoose et al. (2010) in the CHIMERE regional chemistry-transport model. This simple parameterisation is based on two variables, leaf area index (LAI) and specific humidity. We have validated the geographical and temporal representativeness of this parameterisation on a large scale by using yearly polyol observations and primary biogenic organic aerosol factors from positive matrix factorisation (PMF) analysis at 11 French measurement sites. For a group of sites in northern and eastern France, the seasonal variation of fungal spore emissions, displaying large summer and small winter values, is correctly depicted. However, the H&S parameterisation fails to capture fungal spore concentrations for a smaller group of Mediterranean sites with less data availability in terms of both absolute values and seasonal variability, leading to strong negative biases, especially during the autumn and winter seasons. Two years of CHIMERE simulations with the H&S parameterisation have shown a significant contribution of fungal spore OA to PM10 mass, which is lower than 10 % during winter and reaches up to 20 % during summer in high-emission zones, especially over large forested areas. In terms of contributions to organic matter (OM) concentrations, the simulated fungal spore contribution in autumn is as high as 40 % and reaches at most 30 % of the OM for the other seasons. As a conclusion, the fungal spore OA contribution to the total OM concentrations is shown to be substantial enough to be considered a major PM10 fraction and should then be included in state-of-the-art chemistry-transport models. [ABSTRACT FROM AUTHOR]

Fungal spore organic aerosol emissions have been recognised as a significant source of particulate matter as PM10; however, they are not widely considered in current air quality models. In this work, we have implemented the parametrisation of fungal spore organic aerosol (OA) emissions introduced by Heald and Spracklen (2009) (H&S) and further modified by Hoose et al. (2010) in the CHIMERE regional chemistry-transport model. This simple parametrisation is based on two variables which are leaf area index (LAI) and specific humidity. We have validated the geographical and temporal representativeness of this parametrisation on a large scale by using yearly polyol observations and primary biogenic organic aerosol factors from PMF analysis at 11 French measurement sites. For a group of sites in northern and eastern France, the seasonal variation of fungal spore emissions, displaying large summer and small winter values, is correctly depicted. However, the H&S parametrisation fails to capture fungal spore concentrations for a smaller group of Mediterranean sites with less data availability both in terms of absolute values as well as seasonal variability, leading to strong negative biases especially during the autumn and winter seasons occur. Two years of CHIMERE simulations with the H&S parametrisation have shown a significant contribution of fungal spore OA to PM10 mass, lower than 10 % during winter, and reaching up to 20 % during summer in high emission zones, especially over large forested areas. In terms of contribution to organic matter (OM) concentrations, the simulated fungal spore contribution in autumn is as high as 40 % and reaches at most 30 % of OM for other seasons. As a conclusion, the fungal spore OA contribution to total OM concentrations is shown to be substantial enough to be considered as a major PM10 fraction and shall then be included in state-of-the-art chemistry transport models. The H&S parametrisation shows satisfactory results over northern and eastern France, but may underestimate concentrations for Mediterranean areas that may indicate missing factors influencing emissions or a missing source of spores. [ABSTRACT FROM AUTHOR]

The dynamic response of a railway track has been investigated by analytical or numerical models. When rail supports (sleepers) or foundation contain defects, the damage reduces stiffness and the track becomes non-uniform. This paper presents a new analytical model to calculate the dynamic responses of a railway track on a non-uniform foundation. In this model, the rail is considered as an infinite beam resting on equidistant supports and subjected to moving forces. The sleepers responses are stable provided that there is a sufficiently large distance between the applied forces and the defective area. By combining this condition and the dynamic equation of the beam, we can deduce a relation between the reaction forces in the supports and the displacement of the beam. This relation does not depend on supports and foundation behaviors. Hence, we can calculate the dynamic response of the track by using the constitutive laws of the supports. The responses can be obtained finally with direct or with iterative techniques. The numerical examples show that a defective zone causes an increase in the rail displacement at the defective zone and overloads the neighbor supports. [ABSTRACT FROM AUTHOR]

The aerosol optical depth (AOD) is a derived measurement useful to investigate the aerosol load and its distribution at different spatio–temporal scales. In this work we use long–term (2000–2021) MAIAC (Multi–Angle Implementation of Atmospheric Correction) retrievals with 1 km resolution to investigate the climatological AOD variability and trends at different scales in Europe: a continental (30–60° N; 20° W–40° E), a regional (100x100 km2) and an urban local scale (3x3 km2). The AOD climatology at the continental scale shows the highest values during summer (JJA) and the lowest during winter (DJF) seasons. Regional and urban local scales are investigated for twenty–one cities in Europe including capitals and large urban agglomerations. Analyses show AOD average (550 nm) values between 0.06 and 0.16 at the urban local scale, while also displaying a strong north–south gradient. This gradient corresponds to a similar one in the European background, with higher AOD being located over the Po–Valley, the Mediterranean basin, and Eastern Europe. Average enhancements of the local with respect to regional AOD of 57 %, 55 %, 39 % and 32 % are found for large metropolitan centers such as Barcelona, Lisbon, Paris and Athens respectively, suggesting a non–negligible enhancement to the aerosol burden through local emissions. Negative average deviations are observed for other cities, such as Amsterdam (–17 %) and Brussels (–6 %) indicating higher regional background signal and suggesting a heterogeneous aerosol spatial distribution that conceals the urban local signal. Finally, negative statistically significant AOD trends for the entire European continent are observed. A stronger decrease rate at the regional scale with respect to the local scale one occurs for most of the cities under investigation. [ABSTRACT FROM AUTHOR]

Tuned mass dampers (TMDs) are proposed as a solution to reduce the involuntary tremor at the upper limb of a patient with postural tremor. The upper limb is modeled as a three-degrees-of-freedom rotating system in the vertical plane, with a flexion-extension motion at the joints. The measured extensor carpi radialis signal of a patient is used to excite the dynamic model. We propose a numerical methodology to optimize the parameters of the TMDs in the frequency domain combined with the response in the time domain. The objective function for the optimization of the dynamic problem is the maximum angular displacement of the wrist joint. The optimal stiffness and damping of the TMDs are obtained by satisfying the minimization of the selected objective function. The considered passive absorber is a cantilever beam–like TMD, whose length, beam cross-sectional diameter, and mass position reflect its stiffness for a chosen additional mass. A parametric study of the TMD is conducted to evaluate the effect of the TMD position along the hand segment, the number of TMDs, and the total mass of TMDs. The sensitivity of the TMD to a decrease of its modal damping ratio is studied to meet the range of stainless steel. TMDs are manufactured using stainless steel beams of the same length (9.1 cm) and cross-sectional diameter (0.79 mm), for which the mass (14.13 g) position is adjusted to match the optimal frequency. Three TMDs holding a mass of 14.13 g each cause 89% reduction in the wrist joint angular displacement. [ABSTRACT FROM AUTHOR]

Particulate matters with a diameter of less than 10 µm (PM10) or less than 2.5 µm (PM2.5) are major air pollutants. Their relationship to psychiatric disorders has not yet been extensively studied. We aimed to explore the relationship between PM10 and PM2.5 air pollution peaks and the daily number of emergency visits for psychotic and mood disorders. Clinical data were collected from the Emergency Department of a Paris suburb (Créteil, France) from 2008 to 2018. Air pollution data were measured by the Paris region air quality network (Airparif) and collected from public databases. Pollution peak periods were defined as days for which the daily mean level of PM was above nationally predefined warning thresholds (20 µg/m3 for PM2.5, and 50 µg/m3 for PM10), and the 6 following days. Multivariable analyses compared the number of daily visits for psychotic and mood (unipolar and bipolar) disorders according to pollution peak, using negative binomial regression. After adjustment on meteorological variables (temperature, humidity, amount of sunshine in minutes), the daily number of emergency visits for psychotic disorders was significantly higher during PM2.5 and PM10 air pollution peak periods; while the number of visits for unipolar depressive disorders was higher only during PM10 peak periods (β = 0.059, p-value = 0.034). There were no significant differences between peak and non-peak periods for bipolar disorders. Differences in the effects of PM air pollution on psychotic and mood disorders should be analyzed in further studies. [ABSTRACT FROM AUTHOR]