An Investigation into Forced Convection of a Nanofluid Flowing in a Rectangular Microchannel under the Influence of a Magnetic Field

In line with recent studies,where it has been shown that nanofluids containing graphene have a stronger capacity to boost the heat transfer coefficient with respect to ordinary nanofluids,experiments have been conducted using water with cobalt ferrite/graphene nanoparticles.In particular,a circular channel made of copper subjected to a constant heatflux has been considered.As nanoparticles are sensitive to the presence of a magneticfield,different conditions have been examined,allowing both the strength and the frequency of such afield to span relatively wide ranges and assuming different concentrations of nanoparticles.According to thefindings,the addition of nanoparticles to thefluid causes its rotation speed to increase by a factor of two,whereas ultraviolet radiation plays a negligible role.The amount of time required to attain the maximum rotation speed of the nanofluid and the Nusselt number have been measured under both constant and alternating magneticfields for a ferrofluid with a concentration of 0.5%and atflow Reynolds number of 550 and 1750.

Weak deflection angle and shadow cast by the charged-Kiselev black hole with cloud of strings in plasma

In this study,the gravitational deflection angle of photons in the weak field limit(or the weak deflection angle)and shadow cast by the electrically charged and spherically symmetric static Kiselev black hole(BH)in the string cloud background are investigated.The influences of the BH charge Q,quintessence parameterγ,and string cloud parameter a on the weak deflection angle are studied using the Gauss-Bonnet theorem.in addition to studying the influences on the radius of photon spheres and size of the BH shadow in the spacetime geometry of the chargedKiselev BH in string clouds.Moreover,we study the effects of plasma(uniform and non-uniform)on the weak deflection angle and shadow cast by the charged-Kiselev BH surrounded by the clouds of strings.In the presence of a uniform/nonuniform plasma medium,an increase in the string cloud parameter a increases the deflection angleα.In contrast,a decrease in the BH charge Q decreases the deflection angle.Further,we observe that an increase in the BH charge Q causes a decrease in the size of the shadow of the BH.We notice that,with an increase in the values of the parametersγand a,the size of the BH shadow increases,and therefore,the intensity of the gravitational field around the charged-Kiselev BH in string clouds increases.Thus,the gravitational field of the charged-Kiselev BH in the string cloud background is stronger than the field produced by the pure Reissner-Nordstrom BH.Moreover,we use the data released by the Event Horizon Telescope(EHT)collaboration,for the supermassive BHs M87*and Sgr A*,to obtain constraints on the values of the parametersγand a.

Probing Horava-Lifshitz gravity using particle and photon dynamics in the presence of plasma

We study the particle motion around a black hole(BH)in Horava-Lifshitz(HL)gravity with the Kehagias-Sfetsos(KS)parameter.First,the innermost stable circular orbit(ISCO)is obtained for massive particles around the BH in HL gravity.We find that the radii of the ISCOs decrease as the KS parameter decreases,meaning that the parameterΩcauses the orbits of particles to move inward with respect to that of the Schwarzschild BH case.Then,the optical properties of a KS BH are studied in detail,that is,the BH shadow and gravitational weak lensing.We demonstrate that the size of the BH shadow decreases under the influence of the KS parameter.

Discrete time dynamics of a SIRD reinfection model

This paper deals with a discrete-time dynamical system generated by a modified susceptible-infected-recovered-dead model(SIRD model;nonlinear operator)in threedimensional simplex.We introduce a novel approach that incorporates the SIRD model with the quadratic stochastic operator(QSO)that allows for real-time forecasting.The basic reproductive number Ro is obtained.We describe the set of fixed points of the operator and demonstrate that all fixed points are non-hyperbolic.Further,we study the asymptotical behavior of the trajectories of this system and show that SIRD operators havea regularity property.

Quantum effects on the black hole shadow and deflection angle in the presence of plasma

In this study,the optical properties of a renormalization group improved(RGI)Schwarzschild black hole(BH)are investigated in a plasma medium.Beginning with the equations of motion in a plasma medium,we aim to present the modifications in the shadow radius of the RGI BH.To this end,we compute the deflection angle of light in the weak gravity regime for uniform and non-uniform plasma media.Importantly,owing to the plasma media,we discover that the equations of motion for light obtained from the radiating and infalling/rest gas have to be modified.This,in turn,changes and modifies the expression for the intensity observed far away from the BH.Finally,we obtain the shadow images for the RGI BH for different plasma models.Although quantum effects change the background geometry,such effects are minimal,and practically detecting these effects using the current technology based on supermassive BH shadows is impossible.The parameterΩencodes the quantum effects,and in principle,one expects such quantum effects to play significant roles only for very small BHs.However,the effects of plasma media can play an important role in the optical appearance of BHs,as they affect and modify the equations of motion.

Photon motion and weak gravitational lensing in black-bounce spacetime

The effect of spacetime curvature on photon motion may offer an opportunity to propose new tests on gravity theories.In this study,we investigate and focus on the massless(photon)particle motion around blackbounce gravity.We analyze the horizon structure around a gravitational compact object described by black-bounce spacetime.The photon motion and the effect of gravitational weak lensing in vacuum and plasma are discussed,and the shadow radius of the compact object is also studied in black-bounce spacetime.Additionally,the magnification of the image is studied using the deflection angle of light rays.

Shadows and gravitational weak lensing by the Schwarzschild black hole in the string cloud background with quintessential field

In this study,we observe that,in the presence of the string cloud parameter a and the quintessence parameterγ,with the equation of state parameter,ω_(q) = -2/3the radius of the shadow of the Schwarzschild black hole increases as compared with that in the pure Schwarzschild black hole case.The existence of both quintessential dark energy and the cloud of strings increases the shadow size;hence,the strength of the gravitational field around the Schwarzschild black hole increases.Using the data collected by the Event Horizon Telescope(EHT)collaboration for M87*and Sgr A*,we obtain upper bounds on the values of a andγ.Further,we see the effects of a andγon the rate of emission energy for the Schwarzschild black hole.We notice that the rate of emission energy is higher in the presence of clouds of strings and quintessence.Moreover,we study the weak deflection angle using the Gauss-Bonnet theorem.We show the influence of a andγon the weak deflection angle.We notice that both a andγincrease the deflection angleα.

Some Theorems on Leibniz n-Algebras from the Category U_(n)(Lb)

We study the Leibniz n-algebra U_(n)(L),whose multiplication is defined via the bracket of a Leibniz algebra L as[x1,…,xn]=[x1,[…,[xn−2,[xn−1,xn]]…]].We show that U_(n)(L)is simple if and only if L is a simple Lie algebra.An analog of Levi's theorem for Leibniz algebras in U_(n)(Lb)is established and it is proven that the Leibniz n-kernel of U_(n)(L)for any semisimple Leibniz algebra L is the n-algebra U_(n)(L).

Fungal diversity notes 1512–1610: taxonomic and phylogenetic contributions on genera and species of fungal taxa

This article is the 14th in the Fungal Diversity Notes series,wherein we report 98 taxa distributed in two phyla,seven classes,26 orders and 50 families which are described and illustrated.Taxa in this study were collected from Australia,Brazil,Burkina Faso,Chile,China,Cyprus,Egypt,France,French Guiana,India,Indonesia,Italy,Laos,Mexico,Russia,Sri Lanka,Thailand,and Vietnam.There are 59 new taxa,39 new hosts and new geographical distributions with one new combination.The 59 new species comprise Angustimassarina kunmingense,Asterina lopi,Asterina brigadeirensis,Bartalinia bidenticola,Bartalinia caryotae,Buellia pruinocalcarea,Coltricia insularis,Colletotrichum fexuosum,Colletotrichum thasutense,Coniochaeta caraganae,Coniothyrium yuccicola,Dematipyriforma aquatic,Dematipyriforma globispora,Dematipyriforma nilotica,Distoseptispora bambusicola,Fulvifomes jawadhuvensis,Fulvifomes malaiyanurensis,Fulvifomes thiruvannamalaiensis,Fusarium purpurea,Gerronema atrovirens,Gerronema favum,Gerronema keralense,Gerronema kuruvense,Grammothele taiwanensis,Hongkongmyces changchunensis,Hypoxylon inaequale,Kirschsteiniothelia acutisporum,Kirschsteiniothelia crustaceum,Kirschsteiniothelia extensum,Kirschsteiniothelia septemseptatum,Kirschsteiniothelia spatiosum,Lecanora immersocalcarea,Lepiota subthailandica,Lindgomyces guizhouensis,Marthe asmius pallidoaurantiacus,Marasmius tangerinus,Neovaginatispora mangiferae,Pararamichloridium aquisubtropicum,Pestalotiopsis piraubensis,Phacidium chinaum,Phaeoisaria goiasensis,Phaeoseptum thailandicum,Pleurothecium aquisubtropicum,Pseudocercospora vernoniae,Pyrenophora verruculosa,Rhachomyces cruralis,Rhachomyces hyperommae,Rhachomyces magrinii,Rhachomyces platyprosophi,Rhizomarasmius cunninghamietorum,Skeletocutis cangshanensis,Skeletocutis subchrysella,Sporisorium anadelphiae-leptocomae,Tetraploa dashaoensis,Tomentella exiguelata,Tomentella fuscoaraneosa,Tricholomopsis lechatii,Vaginatispora favispora and Wetmoreana blastidiocalcarea.The new combination is Torula sundara.The 39 new records on hosts and geographical distribution comprise Apiospora guiyangensis,Aplosporella artocarpi,Ascochyta medicaginicola,Astrocystis bambusicola,Athelia rolfsii,Bambusicola bambusae,Bipolaris luttrellii,Botryosphaeria dothidea,Chlorophyllum squamulosum,Colletotrichum aeschynomenes,Colletotrichum pandanicola,Coprinopsis cinerea,Corylicola italica,Curvularia alcornii,Curvularia senegalensis,Diaporthe foeniculina,Diaporthe longicolla,Diaporthe phaseolorum,Diatrypella quercina,Fusarium brachygibbosum,Helicoma aquaticum,Lepiota metulispora,Lepiota pongduadensis,Lepiota subvenenata,Melanconiella meridionalis,Monotosporella erecta,Nodulosphaeria digitalis,Palmiascoma gregariascomum,Periconia byssoides,Periconia cortaderiae,Pleopunctum ellipsoideum,Psilocybe keralensis,Scedosporium apiospermum,Scedosporium dehoogii,Scedosporium marina,Spegazzinia deightonii,Torula fci,Wiesneriomyces laurinus and Xylaria venosula.All these taxa are supported by morphological and multigene phylogenetic analyses.This article allows the researchers to publish fungal collections which areimportant for future studies.An updated,accurate and timely report of fungus-host and fungus-geography is important.We also provide an updated list of fungal taxa published in the previous fungal diversity notes.In this list,erroneous taxa and synonyms are marked and corrected accordingly.