227 research outputs found
Reverse flow catalytic membrane reactors for energy efficient syngas production
To improve the recuperative heat exchange, a Reverse Flow Catalytic Membrane Reactor (RFCMR) with porous membranes is proposed in this thesis, in which very efficient heat exchange between the feed and product streams is achieved by using the reverse flow concept (i.e. periodic alternation of the flow direction of the gas through a fixed catalyst bed)
Process Mining in The Rail Industry: A Qualitative Analysis of Success Factors and Remaining Challenges
This paper aims to identify success factors and remaining challenges relevant to the practice of process mining in the rail industry. Process mining is a method for analyzing processes based on event logs. In a case study, we examine three process mining projects performed at the largest rail organization in The Netherlands. Experiences gained in these projects are compared to success factors specified in literature. The projects were analyzed using observations, secondary data collection and semi-structured interviews. We were able to identify all success factors specified in literature in the case study. In addition, several new success factors are identified. These concern challenges regarding the implementation of process mining software, intra-organizational knowledge sharing and continuous availability of event logs. For the additional success factors identified, it was not yet possible to determine if they are industry specific or generic in nature
Prospects for Observing the low-density Cosmic Web in Lyman-alpha Emission
Mapping the intergalactic medium (IGM) in Lyman- emission would yield
unprecedented tomographic information on the large-scale distribution of
baryons and potentially provide new constraints on the UV background and
various feedback processes relevant to galaxy formation. Here, we use a
cosmological hydrodynamical simulation to examine the Lyman- emission
of the IGM due to collisional excitations and recombinations in the presence of
a UV background. We focus on gas in large-scale-structure filaments in which
Lyman- radiative transfer effects are expected to be moderate. At low
density the emission is primarily due to fluorescent re-emission of the
ionising UV background due to recombinations, while collisional excitations
dominate at higher densities. We discuss prospects of current and future
observational facilities to detect this emission and find that the emission of
filaments of the cosmic web will typically be dominated by the halos and
galaxies embedded in them, rather than by the lower density filament gas
outside halos. Detecting filament gas directly would require a very long
exposure with a MUSE-like instrument on the ELT. Our most robust predictions
that act as lower limits indicate this would be slightly less challenging at
lower redshifts (). We also find that there is a large amount of
variance between fields in our mock observations. High-redshift protoclusters
appear to be the most promising environment to observe the filamentary IGM in
Lyman- emission.Comment: 20 pages, 13 figures. Accepted for publication in Astronomy &
Astrophysics. Accepted version contains several revisions following
suggestions made in the review proces
Standardisation of Supporting Processes in Healthcare A case study of the APQC Healthcare Process Classification Framework
Every patient is unique. This is why hospitals are characterised by highly complex and variable processes. We distinguish between two main categories of processes: The primary healthcare process concerned with the cure and care for the patient, and supporting processes such as logistics, planning, and administration. The American Productivity and Quality Center Healthcare Process Classification Framework (APQC-HPCF) is an open standard designed to support the standardisation of supporting processes in healthcare. In this paper, we perform case studies at two of the hospitalâs clinics. Through observations, interviews, and analysis of process descriptions, we establish to which extent the processes described by APQC-HPCF are implemented in practice. This is done to both identify differences between the clinicsâ supporting processes as well as to validate the efficacy of the APQC-HPCF, which has not been previously tested in scientific literature. Results show that the clinics perform nearly all of the prescribed processes. Deviation from the APQC-HPCF is mainly explained by the fact that some of its contents are designed for the American market and do not apply in the Dutch market. The clinics perform some additional supporting processes that are not present in the framework. Also, minor differences in supporting processes between the two clinics were found. The results show that the efficacy of the APQC-HPCF is validated by a large extent but cannot be proven completely
Standardisation of risk screening processes in healthcare through business rules management
In 2012, an audit held by the Netherlands Institute for Accreditation in Healthcare (NIAZ) at the âRivierenlandâ hospital in The Netherlands, concluded that their processes were not sufficiently standardised. One of the suggested improvements was to develop and implement a hospital-wide method for analysing and standardising care processes. This paper focuses on the standardisation of the risk screening process, which is used to assess a number of patient risk factors prior to treatments or hospital admissions. By separating the decision logic of the risk screening processes into a set of business rules, the screening process was standardised to be identical for each risk factor. This allows for the decision logic and the process to be changed independently of each other. Additional business rules were introduced to serve as constraints, thereby limiting the number of performed screening processes depending on the age of the patient and the duration of the treatment or admission. Based on historical data from the year 2013, a retrospective analysis demonstrated potential time savings of around 1600 hours on a yearly basis thanks to the introduction of the new standardised process incorporating business rules. Similar standardisation methods may be useful to other hospitals facing increasingly stringent demands for quality, safety and efficiency
Recreation and hunting differentially affect deer behaviour and sapling performance
Humans are increasingly acknowledged as apex predators that shape landscapes of fear to which herbivores adapt their behaviour. Here, we investigate how humans modify deer space-use and their effects on vegetation at two spatial scales; zones with different types of human use (largescale risk factor) and, nested within that, trails (fine-scale risk factor). In zones with three contrasting types of human activities: 1) no recreation, no hunting, 2) with recreation, no hunting and 3) with recreation and hunting, we linked deer space-use (dropping counts) to browsing intensity, relative growth and survival of planted saplings. Plots were located at two distances to trails (20 versus 100 m) to test how trails affect deer space-use and sapling performance. Additionally, plots were distributed over forest and heathland as risk effects are habitat-dependent. Deer space-use was highest in the zone without recreation or hunting, resulting in higher browsing levels and lower sapling growth and survival, but only in heathland. In contrast, deer space-use and sapling performance did not differ between zones with recreation only and zones with recreation and hunting. Deer dropping counts were lower near trails used for recreation, but this was not associated with browsing impact or sapling performance. Our results show that recreational use modifies deer space-use which is associated with browsing impact on woody vegetation, while seasonal hunting activities in zones with recreation did not have additive year-round effects. Yet, effects were only observed at the larger scale of recreation zones and not near trails. Furthermore, deer space-use was only associated with sapling performance in open heathland, where high visibility presumably increases avoidance behaviour because it increases detectability and decreases escape possibilities. This suggests that recreation creates behaviourally mediated cascading effects that influence vegetation development, yet these effects are context-dependent. We advocate incorporating human-induced fear effects in conservation, management and research
Recreation and hunting differentially affect deer behaviour and sapling performance
Humans are increasingly acknowledged as apex predators that shape landscapes of fear to which herbivores adapt their behaviour. Here, we investigate how humans modify deer space-use and their effects on vegetation at two spatial scales; zones with different types of human use (largescale risk factor) and, nested within that, trails (fine-scale risk factor). In zones with three contrasting types of human activities: 1) no recreation, no hunting, 2) with recreation, no hunting and 3) with recreation and hunting, we linked deer space-use (dropping counts) to browsing intensity, relative growth and survival of planted saplings. Plots were located at two distances to trails (20 versus 100 m) to test how trails affect deer space-use and sapling performance. Additionally, plots were distributed over forest and heathland as risk effects are habitat-dependent. Deer space-use was highest in the zone without recreation or hunting, resulting in higher browsing levels and lower sapling growth and survival, but only in heathland. In contrast, deer space-use and sapling performance did not differ between zones with recreation only and zones with recreation and hunting. Deer dropping counts were lower near trails used for recreation, but this was not associated with browsing impact or sapling performance. Our results show that recreational use modifies deer space-use which is associated with browsing impact on woody vegetation, while seasonal hunting activities in zones with recreation did not have additive year-round effects. Yet, effects were only observed at the larger scale of recreation zones and not near trails. Furthermore, deer space-use was only associated with sapling performance in open heathland, where high visibility presumably increases avoidance behaviour because it increases detectability and decreases escape possibilities. This suggests that recreation creates behaviourally mediated cascading effects that influence vegetation development, yet these effects are context-dependent. We advocate incorporating human-induced fear effects in conservation, management and research
Recreation reduces tick density through fine-scale risk effects on deer space-use
Altered interactions between pathogens, their hosts and vectors have potential consequences for human disease risk. Notably, tick-borne pathogens, many of which are associated with growing deer abundance, show global increasing prevalence and pose increasing challenges for disease prevention. Human activities can largely affect the patterns of deer space-use and can therefore be potential management tools to alleviate human-wildlife conflicts. Here, we tested how deer space-use patterns are influenced by human recreational activities, and how this in turn affects the spatial distribution of the sheep tick (Ixodes ricinus), a relevant disease vector of zoonoses such as Lyme borrelioses. We compared deer dropping and questing tick density on transects near (20 m) and further away from(100 m) forest trails that were either frequently used (open for recreation) or infrequently used (closed for recreation, but used by park managers). In contrast to infrequently used trails, deer dropping density was 31% lower near (20 m) than further away from (100 m) frequently used trails. Similarly, ticks were 62% less abundant near (20 m) frequently used trails compared to further away from (100 m) these trails, while this decline in tick numbers was only 14% near infrequently used trails. The avoidance by deer of areas close to human-used trails was thus associated with a similar reduction in questing tick density near these trails. As tick abundance generally correlates to pathogen prevalence, the use of trails for recreation may reduce tick-borne disease risk for humans on and near these trails. Our study reveals an unexplored effect of human activities on ecosystems and how this knowledge could be potentially used to mitigate zoonotic disease risk
Spatially resolved Kennicutt-Schmidt relation at z â 7 and its connection with the interstellar medium properties
We exploit moderately resolved [O III], [C II] and dust continuum ALMA observations to derive the gas density (n), the gas-phase metallicity (Z) and the deviation from the Kennicutt-Schmidt (KS) relation (Îșs) on âsubâkpc
scales in the interstellar medium (ISM) of five bright Lyman Break Galaxies at the Epoch of Reionization (z â 7). To do so, we use GLAM, a state-of-art, physically motivated Bayesian model that links the [C II]and [O III] surface brightness (ÎŁ[CII], ÎŁ[OIII]) and the SFR surface density (ÎŁSFR) to n, Îșs, and Z. All five sources are characterized by a central starbursting region, where the ÎŁgas vs ÎŁSFR align â10 Ă above the KS relation (Îșs â 10). This translates into gas depletion times in the range tdep â 80 â 250 Myr. The inner starbursting centers are characterized by higher gas density (logâ(n/cmâ3) â 2.5 â 3.0) and higher metallicity (logâ(Z/Zâ) â â0.5) than the galaxy outskirts. We derive marginally negative radial metallicity gradients (âlogâZ â â0.03 ± 0.07 dex/kpc), and a dust temperature (Td â 32 â 38 K) that anticorrelates with the gas depletion time
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