The measurement of accident-proneness

This paper deals with the measurement of accident-proneness. Accidents seem easy to observe, however accident-proneness is difficult to measure. In this paper I first define the concept of accident-proneness, and I develop an instrument to measure it. The research is mainly executed within chemical industry, and the organizations are pictured summarily. The instrument is validated in different ways with different outcomes. On the basis of these outcomes I conclude that the accident-proneness scale has only a limited validity, and each branch of industry probably requires another accident subscale. However for a comparison within chemical industry the instrument seems admissible.

Flow characteristics and exchange in complex biological systems as observed by pulsed-field-gradient magnetic-resonance imaging

Water flow through model porous media was studied in the presence of surface relaxation, internal magnetic field inhomogeneities and exchange with stagnant water pools with different relaxation behavior, demonstrating how the apparent flow parameters average velocity, volume flow and flow conducting area in these situations depend on the observation time. To investigate the water exchange process a two component biological model system consisting of water flowing through a biofilm reactor (column packed with methanogenic granular sludge beads) was used, before and after a heat treatment to introduce exchange. We show that correction of the stagnant fluid signal amplitude for relaxation at increasing observation time using the observed relaxation times reveals exchange between the two fractions in the system. Further it is demonstrated how this exchange can be quantifie

Proton NMR relaxometry as a useful tool to evaluate swelling processes in peat soils

Dramatic physical and physico-chemical changes in soil properties may arise due to temperature and moisture variations as well as swelling of soil organic matter (SOM) under constant conditions. Soil property variations may influence sorption/desorption and transport processes of environmental contaminants and nutrients in natural-organic-matterrich soils. Notwithstanding the studies reported in literature, a mechanistic model for SOM swelling is unavailable yet. The objective of the present study was the evaluation of the swelling of peat soils, considered as SOM models, by 1H NMR relaxometry and differential scanning calorimetry (DSC). Namely, information on the processes governing physical and physicochemical changes of peat during re-hydration were collected. The basic hypothesis of the present study was that the changes are slow and may affect water state as well as amounts of different water types into the peats. For this reason, such changes can be evidenced through the variations of mobility and thermal behaviour of the involved H2O molecules by using 1H NMR relaxometry and DSC. According to the experimental results, a mechanistic model, describing the fundamental processes of peat swelling, was obtained. Two different peats re-wetted at three temperatures were used. The swelling process was monitored by measuring spin-spin relaxation time (T2) over a hydration time of several months. Moreover, DSC, T1 – T2 and T2 – D correlation measurements were done at the beginning and at the end of the hydration. Supplementary investigations were also done in order to discriminate between the swelling effects and the contributions from soil solution, internal magnetic field gradients and/or soil microorganisms to proton relaxation. All the results revealed peat swelling. It was evidenced by pore size distribution changes, volumetric expansion and redistribution of water, increasing amounts of nonfreezable and loosely bound water, as well as formation of gel phases and reduction of the translational and rotational mobility of H2O molecules. All the findings implied that changes of the physical and physicochemical properties of peats were obtained. In particular, three different processes having activation energies comprised in the interval 5 – 50 kJ mol-1 were revealed. The mechanistic model which was, then, developed included water reorientation in bound water phases, water diffusion into the peat matrix and reorientation of SOM chains as fundamental processes governing SOM swelling. This study is of environmental significance in terms of re-naturation and re-watering of commercially applied peatlands and of sorption/desorption and transport processes of pollutants and nutrients in natural organic matter rich soil

A fast 2D image reconstruction algorithm from 1D data for the Gaia mission

A fast 2-dimensional image reconstruction method is presented, which takes as input 1-dimensional data acquired from scans across a central source in different orientations. The resultant reconstructed images do not show artefacts due to non-uniform coverage in the orientations of the scans across the central source, and are successful in avoiding a high background due to contamination of the flux from the central source across the reconstructed image. Due to the weighting scheme employed this method is also naturally robust to hot pixels. This method was developed specifically with Gaia data in mind, but should be useful in combining data with mismatched resolutions in different directions.Comment: accepted (18 pages, 13 figures) will appear in Experimental Astronom

Fine‐scale measurement of diffusivity in a microbial mat with nuclear magnetic resonance imaging

Noninvasive 1H‐nuclear magnetic resonance (NMR) imaging was used to investigate the diffusive properties of microbial mats in two dimensions. Pulsed field gradient NMR was used to acquire images of the H2O diffusion coefficient, Ds, and multiecho imaging NMR was used to obtain images of the water density in two structurally different microbial mats sampled from Solar Lake (Egypt). We found a pronounced lateral and vertical variability of both water density and water diffusion coefficient, correlated with the laminated and heterogeneous distribution of microbial cells and exopolymers within the mats. The average water density varied from 0.5 to 0.9, whereas the average water diffusion coefficient ranged from 0.4 to 0.9 relative to the values obtained in the stagnant water above the mat samples. The apparent water diffusivities estimated from NMR imaging compared well to apparent O2 diffusivities measured with a diffusivity microsensor. Analysis of measured O2 concentration profiles with a diffusion‐reaction model showed that both the magnitude of calculated rates and the depth distribution of calculated O2 consumption/production zones changed when the observed variations of diffusivity were taken into account. With NMR imaging, diffusivity can be determined at high spatial resolution, which can resolve inherent lateral and vertical heterogeneities found in most natural benthic systems

Eenheid in verscheidenheid, een onderzoek naar transcendentie en zingeving, identiteit- en gemeenschapsvorming bij het spiritueel festival Open in het licht van het kritisch humanisme van Harry Kunneman

In brede zin gaat mijn scriptie over de spanningsvelden die zich in onze tijd manifesteren tussen autonomie en gemeenschap en seculiere en religieuze wereldbeelden. In deze tijd is er sprake van een spanningsvol samengaan van toenemende modernisering, secularisering en individualisering aan de ene kant, en een opbloei van nieuwe individueel samengestelde en beleefde vormen van religie en spiritualiteit aan de andere kant. Aan de hand van het spirituele festival Open Up, heb ik onderzocht hoe in hedendaagse spiritualiteit het verlaten van traditionele instituties in naam van de persoonlijke vrijheid en autonomie, paradoxaal zorgt voor nieuwe vormen van geëngageerde zingeving, identiteit- en gemeenschapsvorming. Aan de hand van een narratieve analyse van het spirituele discours en de levensbeschouwelijke praktijken, heb ik de sociologische en antropologische vraag naar de relatie tussen het geïndividualiseerde zelf en een spiritueel-wij onderzocht. Vervolgens heb ik deze geanalyseerd aan de hand van het kritisch-humanisme van Harry Kunneman, en beoordeeld of zij voldoet aan de criteria die hij opstelt voor een postmoderne levensbeschouwing. Ik beargumenteer dat er gesproken kan worden van een postmoderne, posttraditionele spiritualiteit. De verwijzingen naar een transcendente Eenheid of Heelheid die in de spiritualiteit bij Open Up centraal staan, laten de postmoderne ruimte voor pluraliteit en uniciteit open, en lijken deze zelfs te bekrachtigen. Meer specifiek laat ik zien dat er in de levensbeschouwelijke inspiratie bij Open Up, een postmoderne verbinding tot stand komt tussen religieus-metafysische en moderne wereldbeelden. Hierin wordt de autonomie van het individu zowel erkend als overstegen. Net als bij Kunneman staan bij Open Up existentiële en morele leerprocessen centraal, waarin zowel de ontwikkeling van het individu een belangrijke rol speelt, als de verbinding met anderen en een groter geheel en waarin verschillen gerespecteerd en gewaardeerd worden

Functional imaging of plants: A nuclear magnetic resonance study of a cucumber plant

Functional magnetic resonance imaging was used to study transients of biophysical parameters in a cucumber plant in response to environmental changes. Detailed flow imaging experiments showed the location of xylem and phloem in the stem and the response of the following flow characteristics to the imposed environmental changes: the total amount of water, the amount of stationary and flowing water, the linear velocity of the flowing water, and the volume flow. The total measured volume flow through the plant stem was in good agreement with the independently measured water uptake by the roots. A separate analysis of the flow characteristics for two vascular bundles revealed that changes in volume flow of the xylem sap were accounted for by a change in linear-flow velocities in the xylem vessels. Multiple-spin echo experiments revealed two water fractions for different tissues in the plant stem; the spin-spin relaxation time of the larger fraction of parenchyma tissue in the center of the stem and the vascular tissue was down by 17% in the period after cooling the roots of the plant. This could point to an increased water permeability of the tonoplast membrane of the observed cells in this period of quick recovery from severe water los

Working hard but not working out? The impact of cognitively demanding work on physical activity

Contains fulltext : 253674.pdf (Publisher’s version ) (Open Access)Radboud University, 02 november 2022Promotores : Geurts, S.A.E., Beckers, D.G.J., Veling, H.P., Kompier, M.A.J.211 p

Governments’ Responses to the Coronavirus Pandemic clears the Road for their Responses to the Traffic Pandemic

Governments all over the world have been instrumental in limiting the devastating effects of the highly infectious COVID-19 pandemic. Although the success rate of a plethora of completely novel legislations is still yet unknown, there can be little doubt about the intensity of political will and resources allocated to fight the spread and effects of the pandemic. In this perspective piece, a comparison is made between governmental responses worldwide to COVID-19 and their responses to a much longer-lasting and even more devasting pandemic, the catastrophe of road traffic crashes. Comparing these two pandemics highlights the negligible level of attention road traffic crash prevention has received in the past and the valuable lessons that can be drawn for the future