In this paper, the kinetic Theory (KT) for multi-particulate flow has been further extended by incorporating contributions from the rotary movement of particles on key flow parameters. The balance ...laws and constitutive relations for granular mixtures have been re-derived to incorporate contributions from both linear and angular movement of particles in determining the flow parameters. The computed results show similar trend with the existing KT based on equal granular temperature assumption. However, with different granular temperature, the change in flow parameters shows dissimilar trend compared with the previous KT. Flow properties like collisional stress, bulk viscosity of phase i decreases with the increase of the granular temperature of species j and shear viscosity and dilute viscosity increases with the increase of granular temperature of species j. A detail comparison of the computed results for a range of flow properties, based on both equal and unequal granular temperature has been presented in this paper.
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•Kinetic Theory for multi-particulate flow has been improved.•The angular movement of multi-size particles was included in the model.•The model was used to calculate the granular temperature.•Number of collisions increases with the increase of granular temperature.•Collisional stress contribution increases with the increase of granular temperature.
Methamphetamine (METH) abuse is associated with several negative side effects including neurotoxicity in specific brain regions such as the striatum. The precise molecular mechanisms by which METH ...usage results in neurotoxicity remain to be fully elucidated, with recent evidence implicating the importance of microglial activation and neuroinflammation in damaged brain regions. METH interacts with sigma receptors which are found in glial cells in addition to neurons. Moreover, sigma receptor antagonists have been shown to block METH-induced neurotoxicity in rodents although the cellular mechanisms underlying their neuroprotection remain unknown. The purpose of the current study was to determine if the prototypic sigma receptor antagonist, SN79, mitigates METH-induced microglial activation and associated increases in cytokine expression in a rodent model of METH-induced neurotoxicity. METH increased striatal mRNA and protein levels of cluster of differentiation 68 (CD68), indicative of microglial activation. METH also increased ionized calcium binding adapter molecule 1 (IBA-1) protein expression, further confirming the activation of microglia. Along with microglial activation, METH increased striatal mRNA expression levels of IL-6 family pro-inflammatory cytokines, leukemia inhibitory factor (lif), oncostatin m (osm), and interleukin-6 (il-6). Pretreatment with SN79 reduced METH-induced increases in CD68 and IBA-1 expression, demonstrating its ability to prevent microglial activation. SN79 also attenuated METH-induced mRNA increases in IL-6 pro-inflammatory cytokine family members. The ability of a sigma receptor antagonist to block METH-induced microglial activation and cytokine production provides a novel mechanism through which the neurotoxic effects of METH may be mitigated.
•Methamphetamine (METH) can cause hyperthermia and neurotoxicity.•METH results in microglial activation and cytokine upregulation in the CNS.•SN79, a σ receptor ligand, mitigates METH hyperthermia and neurotoxicity in mice.•SN79 also blocks METH-induced microglial activation and cytokine upregulation.•σ receptors are potential drug development targets to mitigate METH-induced effects.
Here, the outcomes of experimental measurements and finite-element simulations are used to develop MATLAB/Simulink models for evaluating the transient dynamic behaviour of the well-known dual-core ...presaturated core fault current limiter (PCFCL), either for single- or three-phase configurations. These models are based on calculating the total flux linkage–current characteristics of the AC coils at different levels of DC biasing current, taking into consideration the induced voltage across the DC coil terminals due to significant flux variation during the fault condition. On the other hand, the time-varying self-inductance and the self-inductance–current characteristics of the PCFCL are directly developed through Simulink modelling. It is worth mentioning that the self-inductance–current characteristic enables an important and quick design optimisation tool for PCFCL, where the dynamic inductance term significantly contributes to the total voltage drop across PCFCL in comparison to the static inductance. These total flux linkage and inductance versus current models can be directly used for modelling the dynamic transient behaviour of PCFCL when attached to any electrical transient programme used for analysing complex electrical power systems, with remarkable accuracy, quicker, and easier for various network scenarios and fault conditions.
This study was aimed to improve the rheological and qualitative properties of the most common bread, wheat bread, by barley pentosanes, which is not optimally utilized although it's many benefits and ...its huge production. Therefore, water-soluble pentosanes (WSP) and water-insoluble pentosanes (WIP) were extracted from barley (Hordeum vulgare) and added to wheat flour at different percentages. Five treatments were prepared: (T1) from flour only, (T2 and T3) adding WSP at levels(1 and 2%), (T4 and T5) adding WIP at the same levels respectively. The results showed significant improvement in rheological and qualitative properties of the dough and bread made from this dough with increasing the level of addition. The water absorption, the mixing time and the stability time of the dough for T3 and T5, increased from (61.9%) to (64.8 and 65.3%) and from (2min) to ( 2.4 and 3 min) and from (11 min) to (17 and 18 min)respectively, as compared with T1 . Additionally, total scores of sensory evaluation increased from (89.1) to (95.7 and 89.3), the specific volume increased from (4.37 cm3/gm) to (4.79 and 4.54 cm3/gm). The chemical composition analysis showed an increase in the percentages of protein and fat for the same treatments ( T3 & T5 ) as the values increased from (9.34%) to (10.55 and 9.98%) and from (0.85%) to (1.03 and 0.94%) respectively. The percentages of fibre and ash were also increased from (1.71%) to (1.89 and 2.10%) and from (0.74%) to (1.68 and 1.65%) respectively. While the total calorie decreased from (2.73.63 cal) to (261.98 and 253.18 cal).
Methamphetamine (METH) exposure results in dopaminergic neurotoxicity in striatal regions of the brain, an effect that has been linked to an increased risk of Parkinson's disease. Various aspects of ...neuroinflammation, including astrogliosis, are believed to be contributory factors in METH neurotoxicity. METH interacts with sigma receptors at physiologically relevant concentrations and treatment with sigma receptor antagonists has been shown to mitigate METH-induced neurotoxicity in rodent models. Whether these compounds alter the responses of glial cells within the central nervous system to METH however has yet to be determined. Therefore, the purpose of the current study was to determine whether the sigma receptor antagonist, SN79, mitigates METH-induced striatal reactive astrogliosis. Male, Swiss Webster mice treated with a neurotoxic regimen of METH exhibited time-dependent increases in striatal gfap mRNA and concomitant increases in GFAP protein, indicative of astrogliosis. This is the first report that similar to other neurotoxicants that induce astrogliosis through the activation of JAK2/STAT3 signaling by stimulating gp-130-linked cytokine signaling resulting from neuroinflammation, METH treatment also increases astrocytic oncostatin m receptor (OSMR) expression and the phosphorylation of STAT3 (Tyr-705) in vivo. Pretreatment with SN79 blocked METH-induced increases in OSMR, STAT3 phosphorylation and astrocyte activation within the striatum. Additionally, METH treatment resulted in striatal cellular degeneration as measured by Fluoro-Jade B, an effect that was mitigated by SN79. The current study provides evidence that sigma receptor antagonists attenuate METH-induced astrocyte activation through a pathway believed to be shared by various neurotoxicants.
•Neurotoxic methamphetamine (METH) causes astrogliosis in the striatum.•METH also increases astrocytic OSMR and pSTAT3 expression.•SN79, a σ receptor antagonist, mitigates these METH-induced changes in astrocytes.•Neurotoxic METH also induces striatal cell degeneration which can be mitigated by SN79.•σ Receptors can be targeted to attenuate METH-induced changes in astrocytes following neurotoxic exposures.
The influence of particle concentration on the drag force of a particle deserves attention when using the Lagrangian Particle Tracking methods for the prediction of industrial type gas-solid flows. ...The Lagrangian approach is best suited to applications where the solids volume fraction is low, and the effect of particle concentration can be ignored. In the present work, a 3D time dependent numerical analysis is performed to study the effect of Lagrangian model improvements to replicate experimental studies of straight horizontal pipe flow and flow through a 90° horizontal-to-vertical bend. The present predictions are compared with published experimental data of Tsuji and Morikawa (1982), and Yilmaz (1997). Special attention is paid to influence of particle mass-flow rates and conveying velocity on the particle motion within the system. This study used a CFX-4 package, where the ability to modify the code was necessary to include particle model improvements. These improvements included implementing a newly drag force model developed as a part of this research work. Particle-wall collision and particle-particle collision models developed by Sommerfeld (1992), and Sommerfeld (2001) are also implemented in the CFD model. The standard k–ε dispersed turbulence model was utilized as the predictions for the gas phase only gave similar predicted axial velocity compared to the more computationally demanding Reynolds stress model. The results showed that the inclusion of the various improvements lead to reasonable predicted particle velocities in both the upper and lower regions of the straight horizontal pipe which denote the dilute and dense regions respectively. It was also found that the inclusion of the rough-wall particle wall collision model decreases the axial particle velocity in the lower region where the bulk of the particle wall collisions occur. While the inclusion of the particle collision models tends to disperse the particles away from the lower region resulting in a less dense lower section and a distinctly more homogenous particle distribution compared with the standard model predictions. Further, the increase in particle concentration leads to a reduction in axial velocity due to a loss of momentum through particle-wall and particle-particle collisions. Finally, the improved CFD model best predicted both the reduction and increase in the particle velocities in the different regions.
Fluidized bed technology has diverse industrial applications ranging from the gasification of coal in the power industry to chemical reactions for the plastic industry. Due to their complex chaotic ...non-linear behaviour understanding the hydrodynamic behaviour in fluidized beds is often limited to pressure drop measurements and a mass balance of the system. Computational fluid dynamics has the capability to model multiphase flows and can assist in understanding gas–solid fluidized beds by modeling their hydrodynamics. The multiphase Eulerian–Eulerian gas–solid model, extended and validated here improves on the kinetic theory of granular flow by including a closure term for the quasi-static stress associated with the long term particle contact at high solid concentrations. Similar quasi-static models have been widely applied to slow granular flow such as chute flow, flow down an incline plane and geophysical flow. However combining the kinetic theory of granular flow and the quasi-static stress model for the application of fluidized beds is limited. The objective of the present paper is to compare two quasi-static stress models to the experimental fluidized bed data of Bouillard et al.
4. A quasi-static granular flow model (QSGF) initially developed by Gray and Stiles 18 is compared to the commonly used Srivastava and Sundaresan
37. Both models show good agreement with the experimental bubble diameter and averaged porosity profiles. However only the QSGF model shows a distinct asymmetry in the bubble shape which was documented by Bouillard et al.
4.
This article presents an extended multiphase Eulerian–Eulerian, gas–solid model which improves on the kinetic theory of granular flow by including a closure term for the quasi-static stress. Simulations of a bubble's growth and its travel through a two-dimensional fluidized bed are compared to results from a quasi-static stress model and experimental measurements. Results show the model agrees well with the experimental bubble diameter and averaged voidage profiles.
Display omitted Average axial porosity profiles at x
=
0.10
m from the bed centerline.
A traumatic pseudoaneurysm of the superficial temporal artery is a rare vascular lesion that typically occurs after blunt trauma to the temporal region. It accounts for only 1% of all traumatic ...aneurysms. These pseudoaneurysms need to be appropriately diagnosed and treated without delay as the patient can experience resulting symptoms of severe headache, facial nerve palsy, arterial bleeding, and/or bone erosion. Diagnosis can typically be made with history of trauma along with physical examination followed by confirmation with ultrasound or computer tomography angiogram. The treatment of choice is ligation and resection. We present a case of a 20-year-old male with identified pseudoaneurysm following facial trauma and mandibular fracture repair treated with multiple trials of sclerotherapy. In addition, this report will review additional management options and diagnosis techniques for superficial temporal artery (STA) pseudoaneurysms.
•A CFD model was developed with improved source term for bubble break-up and coalescence.•The Sauter mean diameter was in good agreement with the experimental data.•The velocity profile and time ...averaged axial liquid hold up conform to the available data in the literature.
A computational fluid dynamic (CFD) model was developed with an improved source term based on previous work by Hagesaether et al. 1 for bubble break up and bubble coalescence to carry out numerical prediction of number density of different bubble class in turbulent dispersed flow. The numerical prediction was based on two fluid models, using the Eulerian–Eulerian approach where the liquid phase was treated as a continuum and the gas phase (bubbles) was considered as a dispersed phase. Bubble–bubble interactions, such as breakage due to turbulence and coalescence due to the combined effect of turbulence and laminar shear were considered. The result shows that the radial distributions of number densities of lower bubble classes are more than its higher counterpart. The result also shows that the Sauter mean diameter increases with the increase of height up to 1m and then become steady. Simulated results are found to be in good agreement with the experimental data.
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