Ion-acoustic dipolar vortex in degenerate magnetoplasma with ions/electrons thermal corrections

Nonlinear evolution and propagation characteristics of an ion-acoustic (IA) dipolar vortex are examined in a magnetoplasma that comprises partially degenerate electrons and dynamic ions. The adiabatic ions reduce the quantum magnetohydrodynamic equations to a modified momentum equation. The latter admits a new solution and leads to an evolution equation for the description of a coherent IA dipolar vortex. Numerical analysis reveals that variations in the relevant plasma parameters alter the evolution condition for a stable vortex. The electron exchange-correlation enhances excitation of the vortex as it extends the parametric regime associated with the stable vortex solution. On the contrary, the ion temperature lessens the nonlinear evolution of the vortex. Importantly, a degree of enhancement in the exchange-correlation potential leads to the wave dispersion and-in return-widens the vortex potential spatially. The novel nature of the derived results stresses upon the comprehension of the ordered structures in the compact stars, the magnetic mirrors, the ionosphere, the pinch devices, etc., where thermal corrections significantly impact the waves dynamics.

On the evaluation of stratification based entropy optimized hydromagnetic flow featuring dissipation aspect and Robin conditions

BACKGROUND AND OBJECTIVE

The scrutiny of nonlinear convected flow aspect has continuously appealed researchers attention because of its ample demands in processes like heat exchangers, building insulation, crystal growth, insulation of nuclear reactor, food processing, solar energy and electronic element chilling etc. Taking into consideration the aforesaid utilizations, we modeled differential type (second-grade) nanoliquid considering non-linear mixed convection. The considered differential type nonlinear model elaborates viscoelasticity (elastic and viscous) characteristics. Furthermore the thermal systems emphases on transportation of heat and irreversibility reduction. Especially, evaluating the systems via thermodynamic second relation is essential with the purpose of finding a standard communication between power input prerequisite and heat transference augmentation.

METHOD

Formulated non-dimensional problem is non-linear subject to the assumptions (i.e., Non-linear mixed convection, magnetic field, viscous dissipation, double stratification, Joule heating and convective conditions). Analytic simulations for modeled non-linear systems is not possible. Hence we considered bvp4c scheme for non-linear analysis.

CONCLUSIONS

Velocity [Formula: see text] of second grade (non-Newtonian) fluid intensifies for larger estimations of R* and λ* whereas it dwindles for M. Temperature of nanoliquid deteriorates with S₁ while (θ(η)) rises against Ec. Entropy generation (EG) and (BN) (Bejan number) significantly affected by physical parameters M, α₂ and Br.

Exploring the features for flow of Oldroyd-B liquid film subjected to rotating disk with homogeneous/heterogeneous processes

BACKGROUND AND OBJECTIVE

In the working principle of magnetic devices, the thin film substances are the verified efficient ingredients. Several fields of physics and chemistry has taken advanced studies for the features and utilization of thin film for various aspects. Here, we extracted the features of thin film analysis for time-dependent Oldroyd-B liquid. More specifically, our emphasis is to explore transportation rate of mass/heat by considering mass/energy fluxes. Furthermore, space/temperature dependent heat source/sink are considered. Radiation aspects are taken into account for mathematical modeling of Oldroyd-B liquid. Additionally, Oldroyd-B liquid features are elaborated considering Dufour/Soret aspects. Moreover, the heated surface by convection and chemical aspects remained under consideration while designing the physical model.

METHOD

Feasible variables are employed to achieve nonlinear structure. Computational analysis of such a nonlinear structure is too easy. Therefore, we have engaged numerical technique (bvp4c technique) to solve nonlinear system.

RESULTS

Thickness of liquid film boosts for larger rotation whereas it dwindles against magnetic parameter. Liquid concentration intensifies for Soret number. Transportation rate of mass for larger rotation parameter.

CONCLUSION

Velocity components (Radial, axial, azimuthal) rises via higher ω. Velocity of liquid increase for greater (β₂) while reverse trend is detected for (β₁). Temperature of liquid dwindles for heat sink (A* < 0, B* < 0) parameters while (θ(η)) rises for (A* > 0, B* > 0).

1169 Innovative Exposure to Sleep Medicine for Medical Students

Introduction

Lack of exposure to the field of Sleep Medicine at the medical student level hinders sleep training. Instead of the traditional didactic style, there is a need for innovative collaborative measures to spark interest in the younger generation of learners. The goal of this educational endeavor was to introduce medical students to the field of Sleep Medicine through the platform of Student Interest Group in Neurology (SIGN).

Methods

An interactive session was conducted for SIGN at the University of Minnesota. 24 second-year medical students were divided into 6 groups. The session consisted of introduction, videos of common sleep disorders and interactive briefing afterward. 5-point Likert scale pre and post-session surveys were administered to measure the level of knowledge regarding sleep, familiarity with diagnostic tools, available education, pathways to Sleep Medicine, learner’s interest and impact of the session. Wilcoxon matched-pairs signed-rank test was performed to compare pre- and post-surveys.

Results

There was a significant improvement in measures of students’ knowledge about sleep diagnostic modalities (p =7.8*10-5), education received (p= 3.2*10-5) and pathways to sleep medicine (p=4.1*10-5). Survey also showed improvement in students’ interest in pursuing a Sleep Medicine career (p=0.07). There was no difference in knowledge about the importance of sleep for health (p=0.69). All of the students found the session to be informative.

Conclusion

Early exposure to sleep disorders in interactive format was well received by the medical students with significant improvement in scores regarding sleep education, awareness of diagnostic modalities, career pathway and interest in sleep medicine (p=0.07). Integration of exposure to Sleep Medicine within the medical curriculum in an innovative format should be done to instigate interest in this field. Further larger studies are warranted to evaluate the changes in the students’ interest in the subspecialty with an introduction in the early stages of their career.

Support

 

Entropy optimized stretching flow based on non-Newtonian radiative nanoliquid under binary chemical reaction

BACKGROUND AND OBJECTIVE

Developed electronic mechanisms frequently deal with defies about thermal management from developed phase of heat diminution or generation of available surface area regarding heat exclusion. Such promising defy can be subjugated either by introducing an optimal geometry for chilling equipments or intensifying heat transportation attributes. Nanoliquid in this perspective executes an extraordinary function to address all such matters. Having such usefulness of entropy in view, we formulated the hydromagnetic non-Newtonian nanoliquid in frames of mixed convection. Nanoliquid model comprises Brownian movement and thermophoretic mechanisms. In addition, the novel mass transportation approach featuring binary chemically reacting species is introduced. Energy expression formulation is developed through dissipation phenomenon. Besides, new conditions for Buongiorno model along with radiating flux are considered.

METHOD

We obtained highly nonlinear structure. The computations of such structure are not easy. Thus we employed bvp4c scheme to tackle the nonlinear structure.

RESULTS

Heat transportation rate boosts subject to higher chemical reaction parameter in comparison to thermophoretic factor and Eckert number. The considered rheological model yields viscous nanoliquid situation when material factors are assumed zero. Entropy owing to habituation of respiring air is more in comparison to its frictional factor and during hefty physical action. Entropy subject to respiring air friction under respiratory region is much higher in comparison to air habituation factor.

CONCLUSION

Velocity rises via higher material parameter for thickening situation while opposing trend is witnessed for thinning nature of liquid. Entropy is meaningfully higher owing to breathing air condition rather than frictional impact towards tract. No doubt, entropy have a feasible association with respiratory thermoplasty which assists to handle asthma.

Three dimensional ion-acoustic rogons in quantized anisotropic magnetoplasmas with trapped/untrapped electrons

Three-dimensional (3D) modulational instability (MI) and ion-acoustic (IA) envelopes are studied in a quantized degenerate magnetoplasma, whose constituents are the trapped/untrapped electrons and anisotropic positive ions. By using quantum hydrodynamic equations and the multiscale reductive perturbation technique, a 3D nonlinear Schrödinger equation is derived to account for electron quantization and ion pressure anisotrophy effects. The potential excitations are shown stable (unstable) against the perturbations for K_c<0(K_c>0), where K_c is a critical parameter that accounts for the longitudinal (transverse) dispersion(s) and nonlinearity effects. Numerically, the nonlinear evolution of IA wavepackets into a 3D MI may be revealed in the ranges of low and high frequencies 0<ω≤0.05 and 0.75≤ω≤1.1. The quantizing magnetic field reduces (enhances) the group speed (wave frequency) of IA excitations, concentrating the wave energy to favor the modulational instability. Finite electronic temperature (viz.,T_e≤10keV) enhances the untrapped electrons and significantly widens the instability domain K_c>0. The ionic pressure anisotropy increases the wave frequency (ω), piles up the harmonics under K_c>0, and give rise to modulational instability. The quantized magnetic field and anisotropic pressure reduce the amplitude and spatial extension of the IA rogons. This study is important for understanding the 3D MI and unstable excitations in degenerate plasmas, relevant to white dwarfs, neutron stars, and high-energy density experiments, where strong magnetic field quantizes the dynamics of trapped/untrapped electrons.

Utility of the microcolony method for evaluation of multidrug-resistant tuberculosis patients in Karachi, Pakistan

OBJECTIVE: To compare the microcolony method (MCM) with the reference culture method to evaluate culture conversion in multidrug-resistant tuberculosis (MDR-TB) patients.MATERIAL AND METHODS: Adult patients with Mycobacterium tuberculosis culture-positive MDR-TB undergoing second-line anti-tuberculosis treatment were recruited from two tertiary care chest clinics from January 2013 to October 2014. The MCM was performed in addition to MGIT™ and Löwenstein-Jensen medium (reference method) on sputum samples submitted on a monthly basis.RESULTS: Of 140 patients, culture conversion could be evaluated in 95 patients. The MCM showed 100% agreement with the reference M. tuberculosis culture in 83 of 95 patients who achieved culture conversion. In smear-positive and smear-negative cases, the mean time to positivity was 9.1 and 11.4 days for the MCM and 16.1 and 23.2 days for the reference M. tuberculosis culture respectively. The contamination rate for the MCM was 4.5% in comparison with 6.1% for the reference M. tuberculosis culture. The cost of MCM was estimated to be 30% that of the reference method.CONCLUSION: The MCM can be used in non-urban laboratories as a safe, rapid and cost-effective substitute for the reference M. tuberculosis culture to assess culture conversion in MDR-TB patients.Note: Abstract has been published in International Journal of Mycobacteriology 2015; 4: 159-160.

Spin-orbit torque switching in a T-type magnetic configuration with current orthogonal to easy axes

Different symmetry breaking ways determine various magnetization switching modes driven by spin–orbit torques (SOT). For instance, an applied or effective field parallel to applied current is indispensable to switch magnetization with perpendicular anisotropy by SOT. Besides of this mode, here we experimentally demonstrate a distinct field-free switching mode in a T-type magnetic system with structure of MgO/CoFeB/Ta/CoFeB/MgO where a perpendicular layer with tilted easy axis was coupled to an in-plane layer with a uniaxial easy axis. Current was applied orthogonal to both easy axes and thus also normal to an in-plane effective field experienced by the perpendicular layer. Dynamic calculation shows perpendicular layer could be switched at the same time as the in-plane layer is switched. These field-free switching modes realized in the same T-type magnetic system might expedite the birth of multi-state spin memories or spin logic devices which could be operated by all electric manners.

Spin-orbit torque (SOT) induced magnetization switching facilitates all electric multi-state spin memories and spin logic devices. Here the authors show a new SOT field-free switching mode where the perpendicular layer with tilted easy axis is coupled to an in-plane layer with a uniaxial easy axis.

Experimental investigation and micromagnetic simulations of hybrid CoCr2O4/Ni coaxial nanostructures

Multiphase CoCr₂O₄/Ni core-shell nanowires (NWs) have been synthesized within anodic aluminum oxide membranes by the combination of the sol-gel method with electrodeposition techniques. X-ray diffraction and x-ray photoemission spectroscopy results confirmed the formation of a cubic spinel structure of CoCr₂O₄ shell with space group Fd-3m (227). The morphology and composition of the as-grown NWs were studied by field emission scanning electron microscopy, as well as transmission electron microscopy. The magnetic properties of the CoCr₂O₄ NT shell and hybrid CoCr₂O₄/Ni NWs were measured at low temperature using a physical property measurement system. The temperature dependence of the magnetization curves showed that CoCr₂O₄ NTs undergo a transition from a paramagnetic state to a ferrimagnetic state at about 90 K and a spiral ordering transition temperature near 22 K. An enhanced coercivity and saturation field were observed for the CoCr₂O₄/Ni core-shell NWs compared to the single-phase Ni NWs. Micromagnetic simulation results indicated that there is a strong coupling between the shell and core layers during the magnetization reversal process. The combination of hard CoCr₂O₄ and soft Ni in a single NW structure may have potential applications in future multifunctional devices.

D-Meson Azimuthal Anisotropy in Midcentral Pb-Pb Collisions at sqrt[s]_{NN}=5.02 TeV

The azimuthal anisotropy coefficient v_{2} of prompt D^{0}, D^{+}, D^{*+}, and D_{s}^{+} mesons was measured in midcentral (30%-50% centrality class) Pb-Pb collisions at a center-of-mass energy per nucleon pair sqrt[s_{NN}]=5.02  TeV, with the ALICE detector at the LHC. The D mesons were reconstructed via their hadronic decays at midrapidity, |y|<0.8, in the transverse momentum interval 1<p_{T}<24  GeV/c. The measured D-meson v_{2} has similar values as that of charged pions. The D_{s}^{+} v_{2}, measured for the first time, is found to be compatible with that of nonstrange D mesons. The measurements are compared with theoretical calculations of charm-quark transport in a hydrodynamically expanding medium and have the potential to constrain medium parameters.

Anomalous Evolution of the Near-Side Jet Peak Shape in Pb-Pb Collisions at sqrt[s_{NN}]=2.76 TeV

The measurement of two-particle angular correlations is a powerful tool to study jet quenching in a p_{T} region inaccessible by direct jet identification. In these measurements pseudorapidity (Δη) and azimuthal (Δφ) differences are used to extract the shape of the near-side peak formed by particles associated with a higher p_{T} trigger particle (1<p_{T,trig}<8  GeV/c). A combined fit of the near-side peak and long-range correlations is applied to the data allowing the extraction of the centrality evolution of the peak shape in Pb-Pb collisions at sqrt[s_{NN}]=2.76  TeV. A significant broadening of the peak in the Δη direction at low p_{T} is found from peripheral to central collisions, which vanishes above 4  GeV/c, while in the Δφ direction the peak is almost independent of centrality. For the 10% most central collisions and 1<p_{T,assoc}<2  GeV/c, 1<p_{T,trig}<3  GeV/c a novel feature is observed: a depletion develops around the center of the peak. The results are compared to pp collisions at the same center of mass energy and ampt model simulations. The comparison to the investigated models suggests that the broadening and the development of the depletion is connected to the strength of radial and longitudinal flow.