Impact of autocatalysis chemical reaction on nonlinear radiative heat transfer of unsteady three-dimensional Eyring–Powell magneto-nanofluid flow

The structure of the chaotic attractor of a system is mainly determined by the nonlinear functions in system equations. By using a new saw-tooth wave function and a new stair function, a novel complex grid multiwing chaotic system which belongs to non-Shil’nikov chaotic system with non-hyperbolic equilibrium points is proposed in this paper. It is particularly interesting that the complex grid multiwing attractors are generated by increasing the number of non-hyperbolic equilibrium points, which are different from the traditional methods of realising multiwing attractors by adding the index-2 saddle-focus equilibrium points in double-wing chaotic systems. The basic dynamical properties of the new system, such as dissipativity, phase portraits, the stability of the equilibria, the time-domain waveform, power spectrum, bifurcation diagram, Lyapunov exponents, and so on, are investigated by theoretical analysis and numerical simulations. Furthermore, the corresponding electronic circuit is designed and simulated on the Multisim platform. The Multisim simulation results and the hardware experimental results are in good agreement with the numerical simulations of the same system on Matlab platform, which verify the feasibility of this new grid multiwing chaotic system.     

Importance of Darcy–Forchheimer porous medium in 3D convective flow of carbon nanotubes

This article explores Darcy–Forchheimer 3D flow of water-based carbon nanomaterial (CNTs). A bi-directional linear stretchable surface has been used to create the flow. Flow in porous space is represented by Darcy–Forchheimer expression. Heat transfer mechanism is explored through convective heating. Results for single-wall (SWCNTs) and multi-wall (MWCNTs) carbon nanotubes have been presented and compared. The reduction of partial differential system into nonlinear ordinary differential system is made through suitable variables. Optimal homotopic scheme is used for solutions development of governing flow problem. Optimal homotopic solution expressions for velocities and temperature are studied through graphs by considering various estimations of physical variables. Skin friction coefficients and local Nusselt number are analyzed through plots. Our findings show that the skin friction coefficients and local Nusselt number are enhanced for larger values of nanoparticles volume fraction.     

Synthesis,Crystal Structure,and Spectral Study of a Novel Indenoimidazole Carboxylic Acid Amide

Russian Journal of Organic Chemistry - 3a,8a-Dihydroxy-2,8-dioxo-1,3a,8,8a-tetrahydro-2H-indeno[1,2-d]imidazole-3-carboxamide has been synthesized in 85% yield from ninhydrin and biuret via a green...     

Preconcentration of milk proteins using octadecylated monolithic silica microchip

Sample preparation is a bottleneck in systems for chemical analysis and it is a required step in order to remove interference and preconcentrate the target analytes. Much research in recent years has focused on porous monolithic materials since they are highly permeable to liquid flow and show high mass transfer compared with common packed beds. This study has focused on the use of a glass microchip containing an inorganic silica-based monolithic material modified with octadecyl groups for preconcentration of milk proteins from skimmed cows’ milk that vary in molecular weight, hydrophobicity, and abundance. Comparison between the fabricated device and a commercial cartridge for the preconcentration of proteins in skimmed cows’ milk showed the ability of the device to successfully enrich protein mixtures from the sample. The three replicate experiments showed that the RSD of the mass to charge ratio of milk proteins ranged from 0.01 to 0.46%. In addition, it was found that there were no significant differences between the observed and reported masses of the milk proteins and the relative percentage error of the molecular masses ranged between 0.03 and 0.90%. The fact that the small amounts of sample required and short sample preparation time suggest that this new microfluidic device may be a viable alternative to existing procedures for protein extraction from real samples.     

Selective cyclization of S-substituted pyrimidinethione: Synthesis and antimicrobial evaluation of novel polysubstituted thiazolopyrimidine and thiazolodipyrimidine derivatives

The synthetic strategy is based on alkylation of 4-aryl-N-(4-chlorophenyl)-6-methyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxamide derivatives IV a–g , with some alkyl halides and α-haloketones, namely, methyl iodide, chloroacetonitrile, and phenacyl bromide to give the corresponding S-substituted derivatives Va–c . Treatment of IVa–c with ethyl bromoacetate in ethanol under reflux in the presence of potassium hydroxide solution led to the formation of N-(4-chlorophenyl)-7-methyl-3-oxo-5-(aryl)-2,3-dihydro-5H-thiazolo[3,2-a]pyrimidine-6-carboxamide derivative VIII a–c in a single-step synthesis. On the other hand, compound IVa reacted with α-halo carbonitriles, namely, chloro acetonitrile, and monobromo malononitrile, to produce directly thiazolo[3,2-a]pyrimidine derivatives Xa and Xb , respectively, Compound Xb also reacted with each of formic acid, formamide, and ammonium thiocyanate to form thiazolodipyrimidine derivatives XI–XIII , respectively. Compound VIIIa–c coupled with arenediazonium salts in pyridine to give the corresponding 2-arylhydrazo derivatives XVIa–e . Compounds IV a–g and VIIIa–c were resynthesized under microwave irradiation. Some of the newly synthesized compounds were tested for their antimicrobial activities.     

High-Efficiency Three-Party Quantum Key Agreement Protocol with Quantum Dense Coding and Bell States

We propose a high-efficiency three-party quantum key agreement protocol, by utilizing two-photon polarization-entangled Bell states and a few single-photon polarization states as the information carriers, and we use the quantum dense coding method to improve its efficiency. In this protocol, each participant performs one of four unitary operations to encode their sub-secret key on the passing photons which contain two parts, the first quantum qubits of Bell states and a small number of single-photon states. At the end of this protocol, based on very little information announced by other, all participants involved can deduce the same final shared key simultaneously. We analyze the security and the efficiency of this protocol, showing that it has a high efficiency and can resist both outside attacks and inside attacks. As a consequence, our protocol is a secure and efficient three-party quantum key agreement protocol.

     

A Green-Naghdi Model in a 2D Problem of a Mode I Crack in an Isotropic Thermoelastic Plate

In this article, the generalized thermoelastic theory under Green and Naghdi models are used to study the thermoelastic interaction in an isotropic material containing a finite crack inside the material. The crack boundary is due to a prescribed temperature and stress distribution. Based on the Green-Naghdi type II and type III models, the formulation is applied to generalized thermoelasticity with an appropriate choice of parameters. Numerical solutions of the displacement components, temperature, and stress components are obtained using the finite element method. The results have been verified numerically and are represented graphically. Comparisons were made with expected results from Green and Naghdi model of type III and Green and Naghdi model of type II.     

High-capacity quantum secure direct communication with two-photon six-qubit hyperentangled states

This study proposes the first high-capacity quantum secure direct communication(QSDC) with two-photon six-qubit hyperentangled Bell states in two longitudinal momentum and polarization degrees of freedom(DOFs) of photon pairs, which can be generated using two 0.5 mm-thick type-I β barium borate crystal slabs aligned one behind the other and an eight-hole screen. The secret message can be independently encoded on the photon pairs with 64 unitary operations in all three DOFs. This protocol has a higher capacity than previous QSDC protocols because each photon pair can carry 6 bits of information, not just 2 or 4 bits.Our QSDC protocol decreases the influence of decoherence from environment noise by exploiting the decoy photons to check the security of the transmission of the first photon sequence. Compared with two-way QSDC protocols, our QSDC protocol is immune to an attack by an eavesdropper using Trojan horse attack strategies because it is a one-way quantum communication.The QSDC protocol has good applications in the future quantum communication because of all these features.