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A dynamic fluid system using ozonated water flowing over the bovine peritoneal membrane was developed. Histological analyses were performed to verify the maximum time of ozone exposure to maintain ...

We consider the equations of a rotating incompressible non-Newtonian fluid flow of grade two in a three dimensional torus. We prove two different results of global existence of strong solutions. In the first case, we consider that the elasticity coefficient α is arbitrary and we suppose that the third components of the vertical average of the initial data and of the forcing term are small compared to the horizontal components. In the second case, we consider a forcing term and initial data of arbitrary size but we restrict the size of α. In both cases, we show that the limit system is composed of a linear system and a second grade fluid system with two variables and three components.

Green inhibitors are promising alternatives to toxic corrosion inhibitors. Recently, several researches are conducted to investigate the anti-corrosive property of henna extract in different media....

We introduce a method to train a bio-inspired neural network model, having the characteristics of spiking-timing-dependent interaction and learning, in a manner of supervised learning. We assume the spiking neural network model has the tendency to obey the charge conservation principle or the junction rule on a long (or the learning dynamics) time scale. The tendency makes the distribution of connectivities is determined depending on not only the incoming stimuli to input neurons but also the outgoing stimuli from output neurons as if a solution of the finite elementary method in a fluid system. We apply the learning method to several cases in simulations and find the adoption of the conservation principle exerts desired effects on the neural network learning. Finally, we discuss the significance and the drawbacks of the introduced method and compare it with the supervised learning method implemented by the artificial neural network model.

Background Parabolic trough solar collectors (PTSCs) are used to focus the solar rays on absorber tube. The main aim of this paper is to investigate the effects of applying novel corrugated absorber tube filled with hybrid nanofluid on energy efficiency of a novel double fluid PTSC to achieve the maximum energy efficiency value. Method The Eulerian-Eulerian two-phase model is employed for modelling the PTSC and evaluating its energy efficiency. Numerical study is carried out for different values of Reynolds number (Re), nanoparticles volume fraction (ϕ) and geometrical parameters of novel corrugated absorber tube. Findings It is found that usage of corrugated absorber tube has a significant effect on energy efficiency of single- or double fluid parabolic trough solar collectors. Besides it is understood that usage of double fluid system for collector with smooth channel can also increase the energy efficiency, but not more than using corrugated channel for single fluid collector. Moreover, usage of double fluid system at higher Re is also efficient. The results also show that the efficiency of the PTSC enhances with increasing the nanoparticles concentration. Finally, the optimum model of corrugated absorber tube is presented.

We establish the existence of global solutions and $L^q$ time-decay of a three dimensional chemotaxis system with chemoattractant and repellent. We show the existence of global solutions by the energy method. We also study $L^q$ time-decay for the linear homogeneous system by using Fourier transform and finding Green's matrix. Then, we find $L^q$ time-decay for the nonlinear system using solution representation by Duhamel's principle and time-weighted estimate.

The Keller-Segel-Stokes type system with indirect signal production, as given by { n t + u ⋅ ∇ n = Δ n − ∇ ⋅ ( n S ( n ) ∇ v ) , x ∈ Ω , t > 0 , v t + u ⋅ ∇ v = Δ v − v + w , x ∈ Ω , t > 0 , w t + u ⋅ ∇ w = Δ w − w + n , x ∈ Ω , t > 0 , u t + ∇ P = Δ u + n ∇ ϕ , ∇ ⋅ u = 0 , x ∈ Ω , t > 0 , is considered in a bounded domain Ω ⊂ R N , N ∈ { 2 , 3 } , with smooth boundary, where ϕ ∈ C 2 ( Ω ‾ ) and S ∈ C 2 ( [ 0 , ∞ ) ) . Under the assumption that there exist C S > 0 and α ≥ 0 such that | S ( n ) | ≤ C S ( n + 1 ) − α for all n ≥ 0 , it is shown that for all suitably regular initial data an associated initial-boundary value problem possesses a globally defined bounded classical solution in the case N = 2 . In the case of N = 3 , the conclusion is also true provided α > 1 9 .

The chemotaxis-Stokes system{nt+u·∇n=Δn−∇·(n∇c),ct+u·∇c=Δc−nc,ut=Δu+∇P+n∇ϕ, ∇·u=0, (⋆)is considered in a bounded domain Ω⊂R3 with smooth boundary. The corresponding solution theory is quite wel...

We present regularized phase flield model for description of threephase «fluid–fluid–solid» system, where solid body obeys elastic rheology. It is assumed that one of the liquid phases chemically interacts with the solid one. As the corresponding equations of chemical kinetics, simple model equations describing a bimolecular reaction are considered. A feature of the model under consideration is its preliminary regularization according to quasi-hydrodynamic technique. A fully explicit finite difference approximation of this model is presented. Results of a simulation in two-dimensional setting are presented.

A numerical thermodynamic model is proposed for one of the most important geological fluid systems, the ternary H2O–CO2–NaCl system, at P-T conditions of the middle and lower crust and crust-mantle boundary (up to P = 20 kbar and up to T = 1400°C). The form of the model is analoguous to the model developed earlier for the system H2O–CO2–CaCl2. The model is based on an equation for the Gibbs excess free energy for the fluid H2O–CO2–NaCl, also including terms responsible for the interaction of the fluid with the solid phase of NaCl. The model allows predicting physical-chemical properties of fluids, which participate in the majority of deep petrogenic processes: the phase state of the system (homogeneous or multi-phase fluid, presence or absence of solid NaCl), chemical activities of the components, densities of the fluid phases, and concentrations of the components in the co-existing phases. The P-T dependencies of coefficients of the equation for the Gibbs excess free energy are expressed via molar volumes of water and CO2 at corresponding pressure and temperature. The numerical parameters of the model are obtained by fitting experimental data on the phase state of the fluid system in the range of pressures from 1 to 9 kbar and temperatures from 500 to 930°C. Our parametrization of the P-T dependencies provides applicability of the model for pressures and temperatures beyond the experimental region, namely up to P = 20 kbar and up to T = 1400°C. The validity of the model above these P-T parameters is limited due the properties of the thermodynamic description of the CO2 employed.

There are microfractures and fractures in the carbonate formation of M oilfield, which are easy to cause collapse and borehole instability. On the basis of the liquefiable cleanflo drilling fluid system for open hole completion of horizontal wells designed in the early stage, this paper has carried out the research work of matching acidizing completion fluid system. In this paper, the influence factors, cleaning ability, compatibility, acidizing situation and protection effect of acidizing completion fluid system are evaluated in laboratory. The way of density adjustment and specific dosage of NaCl and hcoona were established to inhibit the formation of salt crystallization. HTA solid acid and JCI are used to counteract each other to reduce the corrosion of casing steel. The core displacement results show that the permeability recovery value of carbonate core after completion fluid treatment can reach 97.54%, and that of sandstone core after treatment can reach 114.7%. Moreover, the completion fluid system also has a certain acidizing effect, which can not only clean and remove the plugging, but also serve as the early induction of acidizing and stimulation.

We consider the coupled chemotaxis–Navier–Stokes system with logistic source term [Formula: see text] in a bounded, smooth domain [Formula: see text], where [Formula: see text] and where [Formula: see text], [Formula: see text] and [Formula: see text] are given parameters. Although the degradation here is weaker than the usual quadratic case, it is proved that for any sufficiently regular initial data, the initial-value problem for this system under no-flux boundary conditions for [Formula: see text] and [Formula: see text] and homogeneous Dirichlet boundary condition for [Formula: see text] possesses at least one globally defined weak solution. And this weak solution becomes smooth after some waiting time provided [Formula: see text].

In this paper we deal with the initial-boundary value problem for a chemotaxis-fluid model involving a complicated nonlinear coupling term, precisely, the following self-consistent system with porous medium diffusion { n t + u ⋅ ∇ n = Δ n m − ∇ ⋅ ( n ∇ c ) + ∇ ⋅ ( n ∇ ϕ ) , x ∈ Ω , t > 0 , c t + u ⋅ ∇ c = Δ c − n c , x ∈ Ω , t > 0 , u t + ∇ P = Δ u − n ∇ ϕ + n ∇ c , x ∈ Ω , t > 0 , ∇ ⋅ u = 0 , x ∈ Ω , t > 0 , under no-flux boundary conditions in a bounded domain Ω ⊂ R 3 with smooth boundary. One of the novelties here is that both the effect of gravity (potential force) on cells and the effect of the chemotactic force on fluid is considered, which leads to the stronger coupling than the most-studied chemotaxis-fluid model for swimming bacteria proposed in [28] . We shall establish the existence of global weak solutions whenever m > 4 3 , thereby supplementing previously gained knowledge on its two-dimensional version.

In this paper, the two-dimensional incompressible chemotaxis fluid with logical source is studied as following: nt+u⋅∇n=Δn−∇⋅(n∇c)+n−n2,ct+u⋅∇c=Δc−nc,ut+u⋅∇u+∇P=Δu−n∇φ,∇⋅u=0. By taking advantage of...

We numerically investigate the linear instability problem of Poiseuille flow in a channel partially filled with a porous medium on the bottom side. We are primarily interested in the influence of the interface momentum distribution including stress continuity and jump interface conditions. A spectral collocation method is applied in solving the fully coupled instability problem arising from the adjacent porous and free channel flows. The results show that the “interface stress coefficient” in a negative range has a larger effect on the trajectory of the eigenvalues than that in the positive range, especially the most unstable mode. Moreover, with a low permeability in the porous region, the interface momentum distribution has less effect on the stability of core flow. And when the “interface stress coefficient” is equal to its minimum negative value, the flow passing through the channel is at its most stable state. If the “interface stress coefficient” varies in a positive range, the degree of fluid stability is predicted to slightly diminish due to stress continuity condition at the interface.

In this paper we are concerned with the initial boundary value problem for the micropolar fluid system in nonsmooth domains with mixed boundary conditions. The considered boundary conditions are of two types: Navier’s slip conditions on solid surfaces and Neumann-type boundary conditions on free surfaces. The Dirichlet boundary condition for the microrotation of the fluid is commonly used in practice. However, the well-posedness of problems with different types of boundary conditions for microrotation are completely unexplored. The present paper is devoted to the proof of the existence, regularity and uniqueness of the solution in distribution spaces.

In the present study, centrifugal pump noise is examined with increasing the redial gapbetween the impeller and pump casing. Increasing the radial gap will be obtained byimpeller trimming. Impeller trimming is the process of decreasing the diameter of animpeller by machining to decrease the energy added to the fluid system. The impellertrimming leads to a reduction both of pump flow rate and head. A closed loop withcirculation pump is designed and fabricated to study the effect of impeller trimming oncentrifugal pump performance and pump noise. Pump performance is obtained for thethree impellers at constant drive speeds. Also, sound pressure level and frequencyspectrum of noise is measured at different circumferential positions around impeller forthree impeller diameters in the same casing. Results of pump performance at constantspeed are found to be in good agreement with affinity laws. Finally, the sound pressurelevel is found to increase with impeller trimming at some locations around the impellerand decreases at others due local changes in flow behavior. فى ھذه الدراسة؛ سيتم البحث فى ز يادة المسافة القطرية بين دفاع المضخة الطاردة المرکزية وغلافھا و تأثير ذلکعلى کفاءة المضخة وکذلک الضوضاء الصادرة منھا. تتم عملية القطع فى حافة دفاع المضخة الطاردة المرکزيةعن طريق اجراء عملية خراطة عليھ بغرضتقليل الطاقة التى يعطيھا للسائل وعندھا فيقل کلا من کمية السائلالخارج من المضخة وضغطھ. تأتى ھذه الطريقة والتى الغرضمنھا تقل يل کمية السائل الخارج من المضخة کبديلعن غلق بلف الطرد تجنبا لما قد يحدث من فقد فى الطاقة. لھذا تعتبر ھذه العملية أکثر توفيرا و کفاءة مقارنة بشراءمضخة جديدة تعطى کمية السائل المطلوبة. وذلک مع الآخذ في الاعتبار تأثير تقليل قطر الدفاع على الضوضاءالمتولدة من المضخة لما فيھ من تأثير على بعضالمستخدمين مثل المستشفيات والبنوک الخ.وضع تصميم لدائرة مياه مغلقة بھا مضخة طاردة مرکزية وتم تصنيعھا لدراسة تأثير القطع فى حافة دفاع المضخةالطاردة المرکزية على أداء المضخة والضوضاء الصادرة منھا. وتم رسم کلا من منحنى الأداء والقدرة للمضخة عند الثلاثة أقطار المشار إليھا عند ثبوت سرعة الدوران وتم التأکد من صحة النتائج وفقا لل (قوانين التقارب).وکذا تم قياس مستوى ضغط الصوت والتحليل الطيفى عند أکثر من موضع لدفاع المضخة وذلک لثلاثة أقطارمختلفة للدفاع عند نفس غطاء المضخة.وجدت النتائج الخاصة بمنحنى الأداء والقدرة موافقة للنتائج النظرية المستنتجة من ال (قوانين التقارب). وقد وجدتزيادة في مستوى ضغط الصوت مع تقليل کمية السائل التى تخرج من المضخة. وکذلک وجدت زيادة فى مستوىضغط الصوت مع تقليل قطر الدفاع عند بعض المواضع ووجد نقصان فى مستوى ضغط الصوت عند مواضعأخرى. يختلف مستوى ضغط الصوت بين موضع لأخر على دفاع المضخة لنفس کمية السائل وقطر الدفاع.

We consider generalized models on coral broadcast spawning phenomena involving diffusion, advection, chemotaxis, and reactions when egg and sperm densities are different. We prove the global-in-time existence of the regular solutions of the models as well as their temporal decays in two and three dimensions. We also show that the total masses of egg and sperm density have positive lower bounds as time tends to infinity in three dimensions., 27 pages

In this paper, we investigate the chemotaxis-fluid system with singular sensitivity and logistic source in bounded convex domain with smooth boundary. We present the global existence of very weak solutions under appropriate regularity assumptions on the initial data. Then, we show that system possesses a global bounded classical solution. Finally, we present a unique globally bounded classical solution for a fluid-free system. In addition, the asymptotic behavior of the solutions is studied, and our results generalize and improve some well-known results in the literature, and partially results are new.

This paper is devoted to investigating the existence and uniqueness of mild solution to the 3D incompressible micropolar fluid system in the Fourier-Herz framework. By taking advantage of microlocal analysis and the mutual effect in the same frequency range of convection term, we give a special initial data (u0, ω0) whose norm of $$F\dot B_{1, q}^{- 1}\left({q > 2} \right)$$ is arbitrarily small, however, the couple (u0, ω0) produces a solution which is arbitrarily large in $$F\dot B_{1, q}^{- 1}$$ after an arbitrarily short time. This implies the system is ill-posed in the sense of “norm inflation” as q > 2.

A nonlocal form of a two-layer fluid system is proposed by a simple symmetry reduction, then by applying multiple scale method to it a general nonlocal two place variable coefficient modified KdV (VCmKdV) equation with shifted space and delayed time reversal is derived. Various exact solutions of the VCmKdV equation, including elliptic periodic waves, solitary waves and interaction solutions between solitons and periodic waves are obtained and analyzed graphically. As an illustration, an approximate solution of the original nonlocal two-layer fluid system is also given.