In a fluidized bed, the drag force acts to oppose the downward force of gravity on a particle, and thus provides the main mechanism for fluidization. Drag models that are employed in large-scale ...simulations of fluidized beds are typically based on either fixed-particle beds or the sedimentation of particles in liquids. In low-Reynolds-number (
$Re$
) systems, these two types of fluidized beds represent the limits of high Stokes number (
$St$
) and low
$St$
, respectively. In this work, the fluid–particle drag behaviour of these two regimes is bridged by investigating the effect of
$St$
on the drag force in low-
$Re$
systems. This study is conducted using fully resolved lattice Boltzmann simulations of a system composed of fluid and monodisperse spherical particles. In these simulations, the particles are free to translate and rotate based on the effects of the surrounding fluid. Through this work, three distinct regimes in the characteristics of the fluid–particle drag force are observed: low, intermediate and high
$St$
. It is found that, in the low-
$Re$
regime, a decrease in
$St$
results in a reduction in the fluid–particle drag. Based on the simulation results, a new drag relation is proposed, which is, unlike previous models, dependent on
$St$
.
Rheumatoid arthritis (RA) is an autoimmune disease characterized by joint inflammation. The presence of autoantibodies in the sera of RA patients has provided many clues to the underlying disease ...pathophysiology. Based on the presence of several autoantibodies like rheumatoid factor (RF), anti-citrullinated protein antibodies (ACPA), anti-carbamylated protein antibodies (anti-CarP), and more recently anti-acetylated protein antibodies RA can be subdivided into seropositive and seronegative disease. The formation of these autoantibodies is associated with both genetic and environmental risk factors for RA, like specific human leukocyte antigen (HLA) alleles and smoking. Autoantibodies can be detected many years before disease onset in a subset of patients, suggesting a sequence of events in which the first autoantibodies develop in predisposed hosts, before an inflammatory response ensues leading to clinically apparent arthritis. Research on the characteristics and effector functions of these autoantibodies might provide more insight in pathophysiological processes underlying arthritis in RA. Recent data suggests that ACPA might play a role in perpetuating inflammation once it has developed. Furthermore, pathophysiological mechanisms have been discovered supporting a direct link between the presence of ACPA and both bone erosions and pain in RA patients. In conclusion, investigating the possible pathogenic potential of autoantibodies might lead to improved understanding of the underlying pathophysiological processes in rheumatoid arthritis.
•Particle-resolved simulations of a cylindrical particle intruding in a granular bed.•Granular beds of spheres and short cylinders have been considered.•Friction and bed packing largely determine the ...fate of the intruding particle.•There is a clear need for experiments to validate and refine numerical methodology.
The way a rigid cylindrical particle falls through a viscous Newtonian liquid into a loosely packed granular bed of smaller and lighter particles has been studied numerically. This solid-liquid flow system has been solved with the lattice-Boltzmann method combined with an immersed boundary method for explicitly imposing no-slip at the particle surfaces. We study the effect of the orientation of the cylinder (vertical and horizontal), its settling speed (the Reynolds numbers at impact is of the order of 100), and its density (relative to liquid and bed density) on the depth of penetration into the granular bed. The simulation results are particularly sensitive to the friction between particles as parameterized through friction coefficients (varied in the range 0.15 – 0.50). The results have practical relevance for particles getting immobilized – or even buried – in granular beds. More importantly, the simulation cases have been designed such as to allow for straightforward experimentation the results of which would be valuable for further numerical model development.
The single phase flow field of a gas cyclone has been simulated with a finite volume RANS model and two LES approaches — one with finite volume and one with lattice-Boltzmann discretization. In order ...to evaluate their quality, the modeling results have been compared with LDA velocity measurements taken from the literature. Since the steady-state RANS simulation did not result in a converged solution, an unsteady RANS simulation was performed and used for further evaluations. The peak-levels of the time-averaged tangential velocity are well predicted by the two LES approaches whereas the RANS-based simulation under-predicts them. For the mean axial velocity, all models perform equally well. Velocity fluctuation levels (in terms of the root-mean-square values of the tangential and axial velocity components) are much better predicted by the large eddy simulations as compared to the RANS simulation. This relates to vortex core precession, the frequency of which was analysed for the two LES approaches. It agreed within 10% with experimentally obtained data. In conclusion, unsteady RANS-based simulations on a relatively coarse grid can provide reasonable and industrially relevant results with limited computational effort, whereas simulations that accurately capture the flow physics require a large eddy approach on fine grids.
Three different numerical approaches have been used to simulate the single phase flow field in a gas cyclone: two large eddy models and a RANS model. The components of the velocity vector (axial, radial and tangential) are compared with high-quality laser Doppler anemometry (LDA) data in various sections. The large eddy models agree with the measurements better than the RANS model.
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Large‐eddy simulations of the turbulent flow driven by a Rushton turbine have been coupled to a Lagrangian description of spherical, solid particles immersed in the flow. The working fluid was water, ...whereas the solid particles had the properties of glass beads. Simulations were restricted to a lab‐scale tank (volume 10−2 m3), and relatively low solids volume fractions (up to 3.6%). Two sets of particles were considered with particle dia. of 0.30 mm and 0.47 mm, respectively. It has been investigated to what level of detail the particle motion needs to be modeled in order to meet Zwietering's just suspended criterion. It appeared to be essential to take particle‐particle collisions into account, mainly because of their exclusion effect that prevents unrealistic buildup of particle concentrations closely above the bottom. The simulations give detailed insight in the behavior of the particles, and in the way that the liquid flow is altered by the presence of the particles. The frequency and intensity of particle‐particle collisions, and particle‐impeller collisions, have been investigated. Furthermore, it will be demonstrated that the rotational Reynolds numbers of the big (0.47 mm) particles were of the same order of magnitude as their translational counterparts.
Benthic foraminifera are unicellular eukaryotes found abundantly in many types of marine sediments. Many species survive and possibly reproduce in anoxic habitats, but sustainable anaerobic ...metabolism has not been previously described. Here we demonstrate that the foraminifer Globobulimina pseudospinescens accumulates intracellular nitrate stores and that these can be respired to dinitrogen gas. The amounts of nitrate detected are estimated to be sufficient to support respiration for over a month. In a Swedish fjord sediment where G. pseudospinescens is the dominant foraminifer, the intracellular nitrate pool in this species accounted for 20% of the large, cell-bound, nitrate pool present in an oxygen-free zone. Similarly high nitrate concentrations were also detected in foraminifera Nonionella cf. stella and a Stainforthia species, the two dominant benthic taxa occurring within the oxygen minimum zone of the continental shelf off Chile. Given the high abundance of foraminifera in anoxic marine environments, these new findings suggest that foraminifera may play an important role in global nitrogen cycling and indicate that our understanding of the complexity of the marine nitrogen cycle is far from complete.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background
Recent research addressed the relationship between staff behaviour and challenging behaviour of individuals with an intellectual disability (ID). Consequently, research on interventions ...aimed at staff is warranted. The present study focused on the effectiveness of a staff training aimed at emotional intelligence and interactions between staff and clients. The effects of the training on emotional intelligence, coping style and emotions of support staff were investigated.
Method
Participants were 214 support staff working within residential settings for individuals with ID and challenging behaviour. The experimental group consisted of 76 staff members, 138 staff members participated in two different control groups. A pre‐test, post‐test, follow‐up control group design was used. Effectiveness was assessed using questionnaires addressing emotional intelligence, coping and emotions.
Results
Emotional intelligence of the experimental group changed significantly more than that of the two control groups. The experimental group showed an increase in task‐oriented coping, whereas one control group did not. The results with regard to emotions were mixed. Follow‐up data revealed that effects within the experimental group were still present four months after the training ended.
Conclusions
A staff training aimed at emotional intelligence and staff‐client interactions is effective in improving emotional intelligence and coping styles of support staff. However, the need for more research aiming at the relationship between staff characteristics, organisational factors and their mediating role in the effectiveness of staff training is emphasised.
Invasive lobular breast cancer (ILC) is the second most common type of breast cancer after invasive breast cancer of no special type (NST), representing up to 15% of all breast cancers.
Latest data ...on ILC are presented, focusing on diagnosis, molecular make-up according to the European Society for Medical Oncology Scale for Clinical Actionability of molecular Targets (ESCAT) guidelines, treatment in the early and metastatic setting and ILC-focused clinical trials.
At the imaging level, magnetic resonance imaging-based and novel positron emission tomography/computed tomography-based techniques can overcome the limitations of currently used imaging techniques for diagnosing ILC. At the pathology level, E-cadherin immunohistochemistry could help improving inter-pathologist agreement. The majority of patients with ILC do not seem to benefit as much from (neo-)adjuvant chemotherapy as patients with NST, although chemotherapy might be required in a subset of high-risk patients. No differences in treatment efficacy are seen for anti-human epidermal growth factor receptor 2 (HER2) therapies in the adjuvant setting and cyclin-dependent kinases 4 and 6 inhibitors in the metastatic setting. The clinical utility of the commercially available prognostic gene expression-based tests is unclear for patients with ILC. Several ESCAT alterations differ in frequency between ILC and NST. Germline BRCA1 and PALB2 alterations are less frequent in patients with ILC, while germline CDH1 (gene coding for E-cadherin) alterations are more frequent in patients with ILC. Somatic HER2 mutations are more frequent in ILC, especially in metastases (15% ILC versus 5% NST). A high tumour mutational burden, relevant for immune checkpoint inhibition, is more frequent in ILC metastases (16%) than in NST metastases (5%). Tumours with somatic inactivating CDH1 mutations may be vulnerable for treatment with ROS1 inhibitors, a concept currently investigated in early and metastatic ILC.
ILC is a unique malignancy based on its pathological and biological features leading to differences in diagnosis as well as in treatment response, resistance and targets as compared to NST.
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