1,604 research outputs found

    Laat het stuiven? Duinenbeheer in de Middeleeuwen

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    Evolutions in undirected travel (satisfaction) during the COVID-19 pandemic

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    The COVID-19 pandemic illustrated that undirected travel (UT), or trips taken for their own sake, can partly compensate for a reduction in destination-based trips due to governmental regulations. Consequently, UT (in general, but particularly during the pandemic) may be especially satisfying and therefore important to subjective well-being. However, through the course of the pandemic, changes in UT were anticipated as individuals adapted to a ‘new normal’. This research – conducted in Flanders, Belgium – first investigates whether the characteristics of and satisfaction with UT persisted after one year into the pandemic (April 2020 to May 2021) using longitudinal panel data from two waves (n = 332). Results of paired sample t-tests indicate that UT satisfaction increased though duration of trips decreased, and results of the Sign test indicate that the frequency of UT generally decreased. Second, this research investigates characteristics of individuals with different UT behavior. Six profiles of UT behavior were identified based on starting or stopping UT, increasing or decreasing UT, maintaining UT frequency, or not participating in UT. Chi2 tests identified differences among profiles based on wave 1 UT frequency, most recent trip mode, socio-demographic, and household characteristics. Results indicate that participation in UT might motivate future UT, one to three UT trips per week is a maintainable frequency, UT might be important to those with smaller living spaces and those living with children or other adults, and suggest that attention should be paid to mobility equity, including how and for whom systems are planned. These findings are important to understanding the effects of long-term governmental regulations in response to the COVID-19 pandemic on travel behavior, and how investigating UT might help to challenge and reimagine traditional mobility systems post-pandemic

    On undirected trips, satisfaction, and well-being: Evidence from Flanders (Belgium)

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    Despite having the potential to improve subjective well-being, satisfaction with undirected travel, or travel for its own sake (e.g. taking a walk, bike ride, or joy ride), has not yet been empirically investigated. Using mean-comparison and generalized linear regression models, this study analyzes 1579 undirected trips made by 852 respondents to a survey in Flanders, Belgium during the COVID-19 pandemic lockdown (18 March – 4 May 2020). Undirected travel was found to be longer in duration and more satisfying than results from directed trips in previous literature, with an indication that higher levels of physical activity are important to satisfaction. Undirected travel satisfaction was found to have a clear positive relationship to well-being. As these trips are often active and were found to imply a positive utility of travel, understanding them can be important to policy goals regarding health, sustainability, and improving individual well-being

    A geometrical model of softwood anatomy for fluid mechanics simulations

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    This paper demonstrates a model of softwood geometry that can be used for multiscale modelling of the longitudinal movement of water through spruce wood. Previous results obtained from a high resolution X-ray CT scan and subsequent image analysis of a large number of Norway spruce tracheids were here used to produce a model that can represent the variability in wood anatomy found within a timber joist or log. A demonstration of that model is given

    Photoemission investigation of the electronic structure of Fe-Pd and Fe-Pt alloys

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    A photoemission investigation of Fe-Pd and Fe-Pt transition-metal alloys, using ∼50–150-eV synchrotron radiation, is presented. We consider in particular the spectral distribution of Fe states when approaching the dilute limit. By means of the Cooper minimum in the 4d and 5d photoionization cross section, we identify structures that have mainly Fe minority- or Fe majority-spin character. The relative position of these peaks is discussed in terms of the covalent interaction between Fe 3d and Pd or Pt d states. Also, the strong resemblance between the distribution of Fe states in the Pd-based and in the Pt-based alloys is demonstrated. We find a consistent behavior of interacting d states towards the dilute limit. It is concluded that the Fe states that are observed in the photoemission spectra of the dilute alloys have mainly majority-spin character and are, because of the covalent interaction with host states, widely distributed over the energy range of the host d band. The Fe minority-spin band, which is centered near the Fermi level, gradually empties with increasing Fe dilution

    Discovery of a [WO] central star in the planetary nebula Th 2-A

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    % context About 2500 planetary nebulae are known in our Galaxy but only 224 have central stars with reported spectral types in the Strasbourg-ESO Catalogue of Galactic Planetary Nebulae (Acker et al. 1992; Acker et al. 1996) % aims We have started an observational program aiming to increase the number of PN central stars with spectral classification. % methods By means of spectroscopy and high resolution imaging, we identify the position and true nature of the central star. We carried out low resolution spectroscopic observations at CASLEO telescope, complemented with medium resolution spectroscopy performed at Gemini South and Magellan telescopes. % results As a first outcome of this survey, we present for the first time the spectra of the central star of the PN Th 2-A. These spectra show emission lines of ionized C and O, typical in Wolf-Rayet stars. % conclusions We identify the position of that central star, which is not the brightest one of the visual central pair. We classify it as of type [WO 3]pec, which is consistent with the high excitation and dynamical age of the nebula.Comment: 3 pages and 2 figures. Paper recommended for publication in A&

    Marine biogenics in sea spray aerosols interact with the mTOR signaling pathway

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    Sea spray aerosols (SSAs) have profound effects on our climate and ecosystems. They also contain microbiota and biogenic molecules which could affect human health. Yet the exposure and effects of SSAs on human health remain poorly studied. Here, we exposed human lung cancer cells to extracts of a natural sea spray aerosol collected at the seashore in Belgium, a laboratory-generated SSA, the marine algal toxin homoyessotoxin and a chemical inhibitor of the mammalian target of rapamycin (mTOR) pathway. We observed significant increased expression of genes related to the mTOR pathway and Proprotein convertase subtilisin/kexin type 9 (PCSK9) after exposure to homoyessotoxin and the laboratory-generated SSA. In contrast, we observed a significant decrease in gene expression in the mTOR pathway and of PCSK9 after exposure to the natural SSA and the mTOR inhibitor, suggesting induction of apoptosis. Our results indicate that marine biogenics in SSAs interact with PCSK9 and the mTOR pathway and can be used in new potential pharmaceutical applications. Overall, our results provide a substantial molecular evidence base for potential beneficial health effects at environmentally relevant concentrations of natural SSAs

    ABRASIVE WEAR BY TiO 2 ON HARD AND LOW FRICTION COATINGS

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    ABSTRACT Several components in paint and plastic industry, like mixers, extrusion screws and dies, injection moulds, suffer heavily from abrasive wear. This wear is mainly induced by the presence of TiO 2 in the paint or in the plastic blend. Coating technology offers a solution to increase the wear resistance and consequently the lifetime of those components. The aim of this study is the evaluation of the micro-abrasive wear resistance of a range of commercially available hard and/or low friction coatings against rutile particles. Therefore, ball cratering tests EXPERIMENTAL SET-UP The tests were performed on a TE66 micro-scale abrasion tester manufactured by Plint. As abrasive suspensions, a typical rutile powder with small particle size (Ø 0.1-0.4 µm) and spherical grains in distilled water was used. Ball bearing steel was used as counterbody. The selected coatings ranged from hard ceramic coatings to softer low friction coatings. Four PVD coatings were used (TiN, CrN, TiCN and low temperature CrN), one CVD (TiN) and three PACVD (DLC and diamond-like nanocomposites Dylyn ® a-C:H/a-Si:O) TEST RESULTS AND EVALUATION The micro abrasion test resulted in a clear ranking of the selected coatings in function of the wear coefficient. In general, the hard ceramic coatings have the lowest wear coefficient. DLC and CrN performed very well. The softer coating types which are designed for reduction of the surface energy, such as NiP+PTFE, show an increase in wear of three orders of magnitude. However, there is no evidence for a close correlation between the wear rate and the coating hardness measured by depth sensing indentation. Only when the three very similar PACVD coatings are considered separately, the wear coefficient is significantly increasing with decreasing coating hardness. The results are obtained by using the extended Archard equation: with K c and K s are the wear coefficients of the coating and substrate respectively, V c and V s the measured wear volumes and SN the sliding distance multiplied by the applied load. Different ways of implementing equatio
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