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Magnetic drug delivery known as smart technique in medicine is basically according to combining the drug inside capsules with the magnetic property or attaching the drug with magnetic surfaces at the micro- and nanoscale. In the present study, magnetic drug delivery in the aortic artery has been investigated. To approach the more realistic problem conditions of blood flow rheology, the effect of parameters such as non-Newtonian viscosity and oscillating input has been put into consideration. Also, the investigated geometrical parameters of arteries of the aortic arch have been chosen similar to the real size. The results indicate that an increase in the diameter of microparticles rises the efficiency of particles absorption. In addition, the influence of changing the direction of the wire carrying electricity and thus changing the direction of magnetic field on magnetic drug delivery has been examined in the geometry of the aortic arc and it is found that the highest particle absorption efficiency takes place in the case that the wire is parallel to the direction of y-axis. As an example, the results show that the rate of absorption efficiency for particles with 3 µm dia is 26.83% and 19.39% when the wire generating magnetic field is parallel to the direction of y-axis and z-axis, respectively, and this value is 10.91% for the case without a magnetic field. The number of particles released from different part of the aortic arch also is affected by the direction of magnetic field. This value illustrates that the percentage of particles released from different states, is equal when the magnetic field is absent and the wire carrying electricity is parallel to y-axis and z-axis. However, the number of particles released from the 2 outputs of the left carotid and left subclavian is less than the other 2 states (i.e., the state when there is not a magnetic field, and the state when the electric current direction is parallel to the y-axis direction) for the state when the wire carrying current is parallel to the z-axis.

An outer-connected dominating set for an arbitrary graph G is a set D ⊆ V such that D is a dominating set and the induced subgraph G[V\D] be connected. In this paper, we focus on the outer-conne...

The authentication of mobile users and establishing a shared key for wireless networks is becoming more emerging, as the number of users who want to roam into a foreign network to use a service inc...

In the present study, the exact solution of a nanofluid flow and mixed convection within a vertical cylindrical annulus with suction/injection, which is adjacent to the radial magnetic field, is presented with regard to the motion of cylinders’ walls. The impact of Brownian motion and shape factor on the thermal state of CuO–water nanofluid is also considered. The influence of such parameters as Hartmann number, mixed convection parameter, suction/injection, volume fraction of nanoparticles and motion of cylinders’ walls on flow and heat transfer is probed. The results show that the shape of the nanoparticles could change the thermal behavior of the nanofluid and when the nanoparticles are used in the shape of a platelet, the highest Nusselt number is obtained (about 2.5% increasement of Nusselt number on internal cylinders’ wall comparison to spherical shape). The results shed light on the fact that if, for example, the external cylinder is stationary and the internal cylinder moves in the direction of z axis, the maximum and minimum heat transfer take place on the walls of internal and external cylinders, respectively (for η = 300, about 15% increasement of Nusselt number on internal cylinders’ wall). Furthermore, the enhancement of radius ratio between two cylinders increases the rate of heat transfer and decreases the shear stress on the internal cylinder’s wall.

In this paper, a new computational method is proposed to solve a class of nonlinear stochastic differential equations (SDEs) driven by fractional Brownian motion (fBm). The method is based on a new class of orthogonal wavelets, namely the Chebyshev cardinal wavelets. These new basis functions have many useful properties such as orthogonality, spectral accuracy, and cardinality. The operational matrices of the derivative and the integration of these new wavelets are derived and used in the implementation of the proposed method. Based on the interpolation property of these new wavelets, a new algorithm is presented for computing nonlinear terms in such problems. The main advantage of the proposed method is the reduction of the problem to a simpler one, which consists of solving a system of nonlinear algebraic equations. The convergence and error analysis of the established method are investigated in the Sobolev space. Moreover, the reliability and applicability of the proposed method are demonstrated by solving several numerical examples. Finally, the application of the proposed method is illustrated by solving two well-known fractional stochastic models in the mathematical finance and the mathematical ecology.

Despite significant advances in left ventricular assist devices and the cannula, unfavorable events leading to the death of patients, including bleeding, infection, neurological disorders, hemolysis, and thrombosis, are still being reported. Local parameters of blood flow, including static flow, vorticity and critical values of shear stress on the wall of ventricle and cannula, increase the risk of thrombosis. Therefore, the analysis of blood flow domains inside the ventricle and cannula is necessary to investigate the probability of forming thrombosis in the cannula of left ventricular assist devices. In this study, blood flow is investigated in a Medtronic DLP 16F clinical cannula by using computational fluid dynamics through three-dimensional modeling of the left ventricle and cannula based on real geometry. Apart from the fact that blood is considered non-Newtonian fluid, the effect of heart movement in the left ventricle is also applied. In this research, blood flow in the cannula has been examined and some problems resulting from the use of the cannulas have been investigated. The results indicate that changing the geometry of input holes, such as their number and size, on the tip of the cannula, alter the probability of forming thrombosis and the standard mode shows a better performance.

The unsteady, viscous flow and mixed convection heat transfer of an incompressible fluid within a vertical concentric cylindrical annulus with time-dependent moving walls are investigated. Fluid is suctioned/injected through the cylinders' walls. Role of movement of the walls on flow and heat transfer inside the vertical annulus is sought. An exact solution of the Navier-Stokes and energy equations is obtained in this problem, for the first time. Here, the transfer of heat is from the hot cylinder walls with constant temperature to the cooler moving fluid. It is interesting to note that the results indicate that the time-dependency of the cylinder walls movement has no effect on the temperature profile. The results also indicate that, compared to other time functions, usage of inverse of time for velocity movement causes significant increase in velocity, stress tensor, and Nusselt number in the vicinity of the moving wall. Also, increasing the mixed convection and suction/injection parameters would increase the Nusselt number and decrease the stress tensor on the inner and outer cylinders no matter what the velocity function is chosen. Therefore, the flow and heat transfer is controllable using the velocity function of the wall movement and change of the other non-dimensional parameters.

This work presents in evaluation in regard to the addition of CNTs dispersion in water ultrasound before it incorporation to concrete mass. The dispersion of carbon Nano tubes have been achieved by use of surfactants and other chemical compounds along with vigorous agitation by signification. The various researches have reported varied results experimenting with different amounts of CNTs and different dispersion techniques leading to a conclusion that 0.03 to 0.5% additions of CNTs to cement enhance the properties greatly. Nano particles are filled the porosity of concrete, therefore reduced permeability and increased the concrete strength and its sustainability. In this research, Nano carbon tube for enhancing the physical properties was used. For the experimental work in this research 5 control specimens 50 x 50 x 50 mm and 5 samples containing 0.03% Nano carbon as percentage of sand and cement, specimens were made based on ASTM C349. With considering the results obtained from experiment, the 0.03% CNT multi wall added to the mortar the strength increased by 39%, this can be attributed to the dispersion of CNT in concrete and protecting concrete from progressive cracks. In the other words, treated CNT in composite concrete matrix, provided more surface connection due to high specific areas resulted transferring more forces, so they provided better connection, therefore preventing matrix surrounding from any micro-structures cracks of the samples were also improved properties greatly.

Carbon nanotubes have emerged as potential reinforcement material for metallic matrices since their discovery in 1991 by Japanese scientist Sumo Iijima. It is observed that carbon nanotubes were comprised of multifunctional properties and were ideal reinforcement material for metallic matrices. In the present work we report the development of carbon nanotubes with multi-walls reinforced commercial purity copper nanocomposites. The carbon nanotubes content was varied from 0.25 to 1.0 wt% in the copper matrix nanocomposites. Here, carbon nanotubes were also nickel coated for improving the interfacial bonding with the copper matrix. In order to obtain the good dispersion of carbon nanotubes in the copper matrix, both materials were subjected to ultrasonication and blending process using ball milling. Further sintered nanocomposites were subjected to upsetting forging process, which involves densification and shape change simultaneously. Microstructure studies were conducted using scanning and transmission electron microscopes to study the dispersion of carbon nanotubes. The effect of carbon nanotubes on the mechanical properties like microhardness and tensile strength of copper matrix nanocomposites is studied in detail.

Given a positive integer k and a graph G = (V, E), a function f from V to the power set of Ik is called a k-rainbow function if for each vertex v ∈ V, f(v)=∅ implies ∪u ∈ N(v)f(u)=Ik where N(v) is the set of all neighbors of vertex v and Ik = {1, …, k}. Finding a k-rainbow function of minimum weight of ∑v ∈ V|f(v)|, which is called the k-rainbow domination problem, is known to be NP-complete for arbitrary graphs and values of k. In this paper, we propose a dynamic programming algorithm to solve the k-rainbow domination problem for graphs with bounded tree-width tw in 𝒪((2k + 1+1)twn) time, where G has n vertices. Moreover, we also show that the same approach is applicable to solve the weighted k-rainbow domination problem with the same complexity. Therefore, both problems of k-rainbow and weighted k-rainbow domination belong to the class FPT, or fixed parameter tractable, with respect to tree-width. In addition to formally showing the correctness of our algorithms, we also implemented these algorithms to illustrate some examples.

The steady, viscous flow and mixed convection heat transfer of an incompressible electrically conducting fluid within a vertical cylindrical annulus with moving walls are investigated. This annulus is under the influence of a radial magnetic field and the fluid is suctioned/injected through the cylinders' walls. An exact solution of the Navier–Stokes equations and energy equation is derived in this problem where heat is transferred from the hot cylinder walls with constant temperature to the cooler moving fluid. The role of the movement of the annulus walls is studied on the flow and heat transfer of the fluid within the annulus, for the first time. The effects of other parameters, including Prandtl number, Hartman number, mixed convection parameter, suction/injection parameter and ratio of the radius, on the behavior of the flow and heat transfer of the fluid is also considered. The results indicate that if, for example, the internal cylinder wall moves in the direction of z-axis and the external cylinder is stationary, the maximum and minimum heat transfer occur on the walls of internal and external cylinders, respectively. Moreover, the augmentation of the radius ratio between the two cylinders increases the rate of heat transfer and decreases the shear stress on the wall of the internal and external cylinders, however, the results on the wall of external cylinder are exactly the reverse. Consequently, by changing the effective parameters used in this paper, the flow of the fluid can be controlled and the heat transfer of the fluid can be improved.

In this paper, we build a novel chaotic coupled lattice mapping with positive Lyapunov exponent, and introduce a novel chaotic image scrambling mechanism. Then, we propose a chaotic image encryption algorithm which uses the introduced chaotic coupled lattice mapping to apply permutation by iteratively applying the introduced chaotic image scrambling mechanism, and diffusing the pixel values. We use a sorting approach rather than quantizing the chaotic floating-point values to construct the diffusion matrix. We also study the security of the proposed algorithm concerning several security measures including brute-force attack, differential attack, key sensitivity, and statistical attacks. Moreover, the proposed algorithm is robust against data loss and noise attacks.

In this paper, an efficient and accurate computational method based on the Legendre wavelets (LWs) together with the Galerkin method is proposed for solving a class of nonlinear stochastic Ito–Volterra integral equations. For this purpose, a new stochastic operational matrix (SOM) for LWs is derived. A collocation method based on hat functions (HFs) is employed to derive a general procedure for forming this matrix. The LWs and their operational matrices of integration and stochastic Ito-integration and also some useful properties of these basis functions are used to transform such problems into corresponding nonlinear systems of algebraic equations, which can be simply solved to achieve the solution of such problems. Moreover, the efficiency of the proposed method is shown for some concrete examples. The results reveal that the proposed method is very accurate and efficient. Furthermore as some useful applications, the proposed method is applied to obtain approximate solutions for some stochastic problems in the mathematics finance, biology, physics and chemistry.

This study attempts to numerically investigate the hydro-thermal characteristics of a ferrofluid (water and 4 vol% Fe 3 O 4 ) in a counter-current horizontal double pipe heat exchanger, which is exposed to a non-uniform transverse magnetic field with different intensities. The magnetic field is generated by an electric current going through a wire located parallel to the inner tube and between two pipes. The single phase model and the control volume technique have been used to study the flow. The effects of magnetic field have been added to momentum equation by applying C++ codes in Ansys Fluent 14. The results show that applying this kind of magnetic field causes kelvin force to be produced perpendicular to the ferrofluid flow, changing axial velocity profile and creating a pair of vortices which leads to an increase in Nusselt number, friction factor and pressure drop. Comparing the enhancement percentage of Nusselt number, friction factor and pressure drop demonstrates that the optimum value of magnetic number for Re ff =50 is between Mn=1.33×10 6 and Mn=2.37×10 6 . So applying non-uniform transverse magnetic field can control the flow of ferrofluid and improve heat transfer process of double pipe heat exchanger.

In this paper, we will study neighborhood system S-approximation spaces, i.e., combination of S-approximation spaces with identical elements except that they have different knowledge mappings, e.g., the knowledge mappings differ due to different experimental conditions and/or sampling methodology. In such situations, there is a risk of contradictory knowledge sets which can lead to different decisions by the same query. These situations are studied in this paper in detail. Moreover, neighborhood system S-approximation spaces are investigated from a three-way decisions viewpoint with respect to different deciders. In addition, completeness results are shown for optimistic and pessimistic neighborhood system S-approximation spaces, i.e., these constructions can be represented by an ordinary S-approximation space. Also, the concept of knowledge significance is proposed and studied in detail, and we have shown that computing a minimal set of knowledge mappings for a neighborhood system S-approximation space is $${\mathbf {NP}}$$NP-hard. Finally, the paper is concluded by two illustrative medical examples.

Background: Long-term treatment with sodium valproate affects the lipid profile and serum homocysteine level. Studies have revealed different results in epileptic patients and there is very little data available regarding the effects of sodium valproate in serum homocysteine level and lipid profile in migraine patients. Objectives: The present study investigated the serum homocysteine level and lipid profile of migraine patients before and after sodium valproate prophylactic therapy. Methods: This study included 52 adult patients with migraines who were candidates for prophylactic migraine treatment by sodium valproate. None of the patients were affected by hyperlipidemia syndromes, cardiovascular disease, stroke, diabetes, gout, carotid stenosis, hypertension, and thyroid, metabolic, or hepatic disorders. The initial peripheral venous blood sample was collected before receiving sodium valproate. Patients received sodium valproate 500 mg daily. The second venous blood sample was taken 3 months later, during the treatment period. Serum levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL), triglyceride (TG), high-density lipoprotein cholesterol (HDL), and homocysteine were measured by standard methods. Results: The mean serum levels of TC, HDL, TG, and homocysteine increased significantly three months after treatment with sodium valproate. The mean serum level of LDL increased after treatment, however, the difference was not significant. Conclusions: Sodium valproate increases the level of serum lipids in patients with migraines; therefore, the risk of cardiovascular diseases may increase by the long-term use of this drug as a prophylactic treatment in migraine patients. Consequently, in patients with other risk factors of cardiovascular disease, sodium valproate should be prescribed with caution.