Impact of Melting Heat Transfer and Variable Characteristics on an MHD Non-Newtonian Shear-Thinning Fluid Flow with Gyrotactic Microorganisms over a Nonlinear Stretched Surface

The objective of this work is to examine how temperature-dependent thermal conductivity and concentration-dependent molecular diffusion affect Reiner-Philippoff nanofluid flow past a nonlinear stretching sheet. At the interface of the elongated surface zero-mass flux and melting heat condition are incorporated. The formulated mathematical problem is simplified by implementing suitable similarity transformations. For the numerical solution bvp4c is utilized. The parameters emerging in the model are discussed versus allied profiles through graphical illustrations. It is perceived that the velocity of the fluid decays on incrementing the Bingham number. The gyrotactic microorganism profile declines on amplifying the Peclet number. The validation of the proposed model is also added to this study. .

Shape Effect of Nanoparticles on Nanofluid Flow Containing Gyrotactic Microorganisms

In this paper,we discussed the effect of nanoparticles shape on bioconvection nanofluid flow over the vertical cone in a permeable medium.The nanofluid contains water,Al2O3 nanoparticles with sphere(spherical)and lamina(non-spherical)shapes and motile microorganisms.The phenomena of heat absorption/generation,Joule heating and thermal radiation with chemical reactions have been incorporated.The similarity transformations technique is used to transform a governing system of partial differential equations into ordinary differential equations.The numerical bvp4c MATLAB program is used to find the solution of ordinary differential equations.The interesting aspects of pertinent parameters on mass transfer,energy,concentration,and density of themotilemicroorganisms’profiles are computed and discussed.Our analysis depicts that the performance of sphere shape nanoparticles in the form of velocity distribution,temperature distribution,skin friction,Sherwood number and Motile density number is better than lamina(non-spherical)shapes nanoparticles.

Laminar MHD natural convection of nanofluid containing gyrotactic microorganisms over vertical wavy surface saturated non-Darcian porous media

Magnetohydrodynamic （MHD） bioconvection of an incompressible electrically conducting nanofluid near a vertical wavy surface saturated porous medium containing both nanoparticle and gyrotactic microorganisms is investigated. The nanofluid is represented by a model that includes both Brownian motion and thermophoresis effects. A suitable set of non-dimensional variables are used to transform the governing boundary layer equations into a dimensionless form. The resulting nonlinear system is mapped to the vertical flat plate domain, and a non-similar solution is used to the obtained equations. The obtained non-similar system is then solved numerically using the fourth-order Runge-Kutta method. The influence of various physical parameters on the local Nusselt number, the local Sherwood number, the local density number of the motile microorganisms, the dimensionless velocity, the dimensionless temperature, and the rescaled density of motile microorganisms is studied. It is found that the local Nusselt number, the local Sherwood number, and the local density number of the motile microorganisms decrease by increasing either the Grashof number or the magnetic field parameter.

Mixed convection in gravity-driven nano-liquid film containing both nanoparticles and gyrotactic microorganisms

Analysis of a gravity-induced film flow of a fluid containing both nanoparticles and gyrotactic microorganisms along a convectively heated vertical surface is presented.The Buongiorno model is applied. Two kinds of boundary conditions, the passive and the active boundary conditions, are considered to investigate this film flow phenomenon.Through a set of similarity variables, the ordinary differential equations that describe the conservation of the momentum, the thermal energy, the nanoparticles, and the microorganisms are derived and then solved numerically by an efficient finite difference technique.The effects of various physical parameters on the profiles of momentum, thermal energy,nanoparticles, microorganisms, local skin friction, local Nusselt number, local wall mass flux, and local wall motile microorganisms flux are investigated. It is expected that the passively controlled nanofluid model can be much more easily achieved and applied in real circumstances than the actively controlled model.

MHD Boundary Layer Flow of a Power-Law Nanofluid Containing Gyrotactic Microorganisms Over an Exponentially Stretching Surface

This study focusses on the numerical investigations of boundary layer flow for magnetohydrodynamic(MHD)and a power-law nanofluid containing gyrotactic microorganisms on an exponentially stretching surface with zero nanoparticle mass flux and convective heating.The nonlinear system of the governing equations is transformed and solved by Runge-Kutta-Fehlberg method.The impacts of the transverse magnetic field,bioconvection parameters,Lewis number,nanofluid parameters,Prandtl number and power-law index on the velocity,temperature,nanoparticle volume fraction,density of motile microorganism profiles is explored.In addition,the impacts of these parameters on local skin-friction coefficient,local Nusselt,local Sherwood numbers and local density number of the motile microorganisms are discussed.The results reveal that the power law index is considered an important factor in this study.Due to neglecting the buoyancy force term,the bioconvection and nanofluid parameters have slight effects on the velocity profiles.The resultant Lorentz force,from increasing the magnetic field parameter,try to decrease the velocity profiles and increase the rescaled density of motile microorganisms,temperature and nanoparticle volume fraction profiles.Physically,an augmentation of power-law index drops the reduced local skin-friction and reduced Sherwood number,while it increases reduced Nusselt number and reduced local density number of motile microorganisms.

Behaviour of Roofing Materials Facing to Micro-Organisms

An accelerated water-streaming test was used to evaluate several roofing materials regarding their behavior to colonization by algae, by closely reproducing the phenomenon of natural biological soiling. A set of roofing materials with defined physical and chemical characteristics was thus investigated against the colonization by algae. Porosity, roughness and chemical composition showed to be factors of influence in the establishment of those micro-organisms.

Insight into Dynamics of Hydromagnetic Flow of Micropolar Fluid Containing Nanoparticles and Gyrotactic Microorganisms at Weak and Strong Concentrations of Microelements: Homotopy Analysis Method

The mathematical model of bioconvection flow of micropolar fluid through a vertical surface containing nanoparticles and gyrotactic microorganisms is presented in this study. In the study, weak and strong concentrations of microstructures are explored. In the energy and concentration equations, the Catteneo-Christov diffusion models are used to explain temperature and concentration diffusions with thermal and solutal relaxation durations, respectively. The governing equations describing the fluid flow are transformed and parameterized through similarity variables. The approximate analytical solution is obtained by using Homotopy Analysis Method (HAM). The impacts of relevant parameters on the various distributions are investigated and illustrated. It is discovered that increasing the value of the micropolar parameter results in an increase in the microrotation distribution for strong concentrations of microstructures while decreasing the microrotation distribution for weak concentrations of microstructures.

High Optical Magnification Three-Dimensional Integral Imaging of Biological Micro-organism

A high optical magnification three-dimensional imaging system is proposed using an optic microscope whose ocular （eyepiece） is retained and the structure of the transmission mode is not destroyed. The elemental image array is captured through the micro lens array. Due to the front diffuse transmission element, each micro lens sees a slightly different spatial perspective of the scene, and a different independent image is formed in each micro lens channel. Each micro lens channel is imaged by a Fourier lens and captured by a CCD. The design translating the stage in x or y provides no parallax. Compared with the conventional integral imaging of micro-objects, the optical magnification of micro-objects in the proposed system can enhanced remarkably. The principle of the enhancement of the image depth is explained in detail and the experimental results are presented.

含微小颗粒的非牛顿生物Sutterby流体在感应磁场旋转圆盘上的流动性

本研究的主要目标是研究含有微小颗粒的非牛顿Sutterby流体的流动性,以及微生物回旋运动引起感应磁场的影响。流动设置在一对圆盘之间,圆盘间充满了含有微小颗粒和趋旋微生物的Sutterby流体。在流动控制中考虑了Arrhenius动力学和热辐射的影响。利用相关的相似变换将所建立的数学模型修改为非线性常微分方程。为了计算非线性常微分方程的数值解,使用微分变换程序(DTM)。对于非线性问题,积分变换技术执行难度大。因此,使用基于Taylor展开的微分变换方法以获得多项式解作为解析解。为了提高公式化数学建模的收敛性,将Padé近似与微分变换方法相结合。讨论了不同无量纲因子对速度、温度场、浓度分布和运动回旋微生物剖面的影响,用表格形式对两块板上的扭矩进行计算和显示。

含趋旋微生物纳米流体在拉伸缸表面上的边界层流动分析

考虑趋旋微生物的影响,研究纳米流体在拉伸缸表面上的稳态二维边界层流动问题.建立控制方程,采用打靶法和Runge-Kutta法进行数值求解,对不同物理参数下的速度场、温度场、浓度场和运动微生物密度场的变化趋势进行图形化分析.结果表明,在靠近缸体表面处,速度、温度、体积分数和微生物密度均随着曲率参数的增大而减小,而在远离缸体表面时变化情况却相反;微生物密度随着Brown运动参数、Peclet数、Schmidt数和生物对流常数的增大而减小,而随着热泳参数的增大而增大.

Antibacterial activity of Lawsonia inermis Linn(Henna) against Pseudomonas aeruginosa

Objective:To investigate the antibacterial activity of henna(Lawsonia inermis Linn) obtained from different regions of Oman against a wide array of micro-organisms.Methods:fresh henna samples were obtained from different regions of Oman as leaves and seeds,100 g fresh and dry leaves and SO g of fresh and dry seeds were separately soaked in 500 mL of ethanol for three days,respectively,with frequent agitation.The mixture was filtered,and the crude extract was collected.The crude extract was then heated,at 48 ℃ in a water bath to evaporate its liquid content.The dry crude henna extract was then tested for its antibacterial activity using well-diffusion antibiotic susceptibility technique.Henna extracts were investigated for their antibacterial activity at different concentrations against a wide array of different micro-organisms including a laboratory standard bacterial strain of Pseudomonas aeruginosa(NCTC 10662)(A aeruginosa) and eleven fresh clinical isolates of P.aeruginosa obtained from patients attending the Sultan Qaboos University Hospital(SQUH).2-Hydroxy-p-Nathoqinone-Tech(2-HPNT, MW=174.16,C_(10)H_40_3) was included as control(at 50%concentration) along with the henna samples tested.Results:Henna samples demonstrated antibacterial activity against all isolates but the highest susceptibility was against P.aeruginosa with henna samples obtained from Al-sharqyia region.Conclusions:Omani henna from Al-sharqyia region demonstrates high in vitro anti-P. aeruginosa activity compared with many henna samples from different regions of Oman.

趋旋性微生物在幂律流体饱和水平多孔层中的热-生物对流稳定性分析

基于趋旋性微生物和幂律流体模型,研究了在含有非 Newton 流体饱和多孔介质中生物对流的线性稳定性问题.利用 Galerkin 数值方法求解了该系统的控制方程,得到生物Rayleigh 数的数值解,讨论了非 Newton 流体的幂律指数对生物对流稳定性在假塑性流体和膨胀性流体间的变化规律.研究结果表明,随着幂律流体的速度增大,幂律指数对生物对流稳定性的影响会发生变化,并且这种变化会受到热Rayleigh 数和生物 Lewis 数的影响.另外,微生物趋旋性特征越明显,生物对流系统就越不稳定,而适当增大非 Newton 流体的幂律指数则有利于系统的稳定性.

牛顿加热条件下近弹性表面Jeffrey流变流体中浮游微生物的游动和纳米流体的悬浮特征

生物对流在可持续、环境友好型燃料电池技术中具有重要作用。这种设计的生物数学模型需要不断的改进,以在实验和计算结果中取得强有力的一致性。实际上,微生物在工业产品的制造过程中,特别是在肥料工业中,运输各种成分。通过与物质散热相关的物理现象来测量分子结构的传热特性。受仿生燃料电池近壁流动现象的启发,本文运用数值方法研究了在靠近伸展壁面的流变性Jeffery流体中运动的旋控微生物的横向游动。通过适当的相似度变换,将主导物理模型转化为非线性ODE系统。采用R-K Fehlberg打靶法在数学软件上进行数值模拟,得到所有物理条件对旋控微生物的速度、温度、浓度和体积分数的影响。结果表明,由于布朗运动和热泳参数的影响,表面的热通量和质量通量以及运动微生物的密度均有所下降。与已有文献进行比较,验证对流边界条件下极限情况结果的有效性。

Sustainable Bio-Conversion of Rice Straw Waste into High Quality Organic Fertilizer

The aim of this study is to investigate the effect of different additives including biochar, effective micro-organisms (EM), animal manure and commercial microbial inoculants on the bioconversion of rice straw. Different compost piles were constructed, and each contained 50 kg of rice straw and mixture of natural rocks to enrich the compost nutritional value. The physical, chemical and biological parameters indicating the decomposition of organic material, maturation and quality of the organic fertilizer product were investigated during the composting process. A rapid increase in compost temperature was obtained in inoculated piles. All piles reached maturation after around 42 days. All analysis of the properties of the final compost products indicated that it was in the range of the matured level and can be used as organic fertilizer without limitation. The highest decomposition rate and highest organic fertilizer quality were obtained in the pile inoculated with EM and 10% biochar compared to other treatments.

Three-dimensional free bio-convection of nanofluid near stagnation point on general curved isothermal surface

In this paper, the three-dimensional nanofluid bio-convection near a stagnation attachment is studied. With a set of similarity variables, the governing equations embodying the conservation of total mass, momentum, thermal energy, nanoparticles and microorganisms are reduced to a set of fully coupled nonlinear differential equations. The homotopy analysis method （HAM）-finite difference method （FDM） technique is used to obtain exact solutions. The effect of various physical parameters on distribution of the motile microorganisms and the important physical quantities of practical interests are presented and discussed.

Propulsive matrix of a helical flagellum

We study the propulsion matrix of bacterial flagella numerically using slender body theory and the regularized Stokeslet method in a biologically relevant parameter regime. All three independent elements of the matrix are measured by computing propulsive force and torque generated by a rotating flagellum, and the drag force on a translating flagellum. Nu- merical results are compared with the predictions of resistive force theory, which is often used to interpret micro-organism propulsion. Neglecting hydrodynamic interactions between different parts of a flagellum in resistive force theory leads to both qualitative and quantitative discrepancies between the theoretical prediction of resistive force theory and the numerical results. We improve the original theory by empirically incorporating the effects of hydrodynamic interactions and propose new expressions for propulsive matrix elements that are accurate over the parameter regime explored.

Bioconvection in Casson nanofluid flow with Gyrotactic microorganisms and variable surface heat flux

This paper presents a two-dimensional unsteady laminar boundary layer mixed convection flow heat and mass transfer along a vertical plate filled with Casson nanofluid located in a porous quiescent medium that contains both nanoparticles and gyrotactic microorganisms. This permeable vertical plate is assumed to be moving in the same direction as the free stream velocity. The flow is subject to a variable heat flux, a zero nanoparticle flux and a constant density of motile microorganisms on the surface. The free stream velocity is time-dependent resulting in a non-similar solution. The transport equations are solved using the bivariate spectral quasilinearization method. A grid independence test for the validity of the result is given. The significance of the inclusion of motile microorganisms to heat transfer processes is discussed. We show, inter alia, that introducing motile microorganisms into the flow reduces the skin friction coefficient and that the random motion of the nanoparticles improves the rate of transfer of the motile microorganisms.

Biomathematical model for gyrotactic free-forced bioconvection with oxygen diffusion in near-wall transport within a porous medium fuel cell

Bioconvection has shown significant promise for environmentally friendly,sustainable“green”fuel cell technologies.The improved design of such systems requires continuous refinements in biomatheatical modeling in conjunction with laboratory and fieldtesting.Motivated by exploring deeper the near-wall transport phenomena involved inbio-inspired fuel cells,in the present paper,we examine analytically and numericallythe combined free-forced convective steady boundary layer flow from a solid verticalflat plate embedded in a Darcian porous medium containing gyrotactic microorganisms.Gyrotaxis is one of the many taxes exhibited in biological microscale transport,andother examples include magneto-taxis,photo-taxis,chemotaxis and geo-taxis (reflecting the response of microorganisms to magnetic field,light,chemical concentration orgravity,respectively). The bioconvection fuel cell also contains difusing oxygen specicswhich mimics the cathodic behavior in a proton exchange membrane(PEM) systei.Thevertical wall is maintained at isosolutal (constant oxygen volume fraction and motilemicroorganism density) and iso-thermal conditions. Wall values of these quantities aresustained at higher values than the ambient temperature and concentration of oxygenand biological microorganism specics.Similarity transformations are applied to renderthe governing partial differential equations for mass,momentum,energy,oxygen speciesand microorganism species density into a system of ordinary differential equations. Theemerging eight order nonlinear coupled,ordinary differential boundary value problemfeatures several important dimensionless control parameters,namely Lewis number(Le),buoyancy ratio paraneter i.e. ratio of oxygen species buoyancy force to thermal buoy-ancy force(Nr), bioconvection Rayleigh number(Rb), bioconvection Lewis number(Lb),bioconvection Peclet number(Pe) and the mixed convection parameter(e) spanning theentire range of free and forced convection. The transformed nonlinear system of equationswith boundary conditions is solved numerically by a finite difference met.hod with centraldifferencing,tridiagonal matrix manipulation and an iterative procedure.Computationsare validated with the symbolic Maple 14.0 software.The influence of buoyancy andbioconvection parameters on the dimensionless temperature,velocity,oxygen concentration and motile microorganism density distribution,Nusselt,Sherwood and gradient ofmotile microorganism density are studied. The work clearly shows the benefit of utilizingbiological organisms in fuel cell design and presents a logical biomathematical modeling framework for simulating such systems.In particular,the deployment of gyrotacticmicroorganisns is shown to stimulate improved transport characteristics in heat andmormentum at the fuel cell wall.

Impact of Domestic Solid Waste Management on Wet Land Water Quality: Case of Abomey-Calavi Municipality in Benin Republic

The waste management is a major environmental challenge in all the countries. In the Republic of Benin, in absence of controlled landfill, the wetlands are filling in by solid household waste to set up housing environments. This study aimed at identifying the various forms of wetlands water pollutions originated by this practice. Physico-chemical parameters of sampling water were determined by using Ionic chromatography and spectrometry of atomic absorption. The microorganisms indicating fecal peril were identified by the conventional techniques of microbiology. Water quality of a witness well was also used to assess the general water quality of the backfilled wetland. The results revealed the water samples collected from backefilled wetlands were mineralized (898.32 ± 6.13 μs/cm), rich in chlorinate (237.80 ± 4.23 mg/L) and nitrates ions (224.10 ± 3.42 mg/L). They are more colored (399.23 ± 3.01 Pt/Co) and more turbid (62.5 ± 2.48 NTU) than those of the unfilled wetlands. The results of microbiological analysis shown the presence of the cysts of Giardia lamblia (590/100 L) and cysts of Entamoeba histolytica (13/100 L) in all water, except those of witness well. The frequency of water contamination by bacteria indicating general degradation is 86.4%. The embankment of the wetlands by the solid household waste leads to the water pollution.

Significance of activation energy and Wu's slip features in Cross nanofluid with motile microorganisms

The current article investigates the impact of the bioconvection in an unsteady flow of magnetized Cross nanofluid with gyrotactic microorganisms and activation energy over a linearly stretched configuration.The analysis has been performed by utilizing the realistic Wu's slip boundary and zero mass flux conditions.The effects of nonlinear thermal radiation and the activation energy are also addressed.The governing flow equations are deduced to a dimensionless form by considering suitable transformations which are numerically targeted via a shooting algorithm.The physical visualization of each physical parameter governing the flow problem has been displayed graphically for distribution of velocity,temperature,concentration and motile microorganisms.The numerical treatment for the variation of skin friction coefficient,local Nusselt number,local Sherwood number and motile density number is performed in tabular forms.