Purpose This paper aims to numerically solve the transient magnetohydrodynamic pulsatile two-dimensional (2D) flow of micropolar blood with heat and mass transfer through the injection of magnetic nanoparticles (MNPs) that are transported inside the blood vessel and captured in the stenosis by the action of an external magnetic field, based on the nanofluids transport model of Buongiorno (which takes into account the Brownian and thermophoretic mechanisms) and micropolar fluids transport model of Eringen (which considers the microrotational movements of blood cells). Design/methodology/approach A transient 2D transport model for blood flow with heat and mass transfer was developed based on the laws of conservation of linear momentum, angular momentum, energy and mass in their dimensionless form. The problem was then solved by means of an analytical approach, a numerical solution applied directly to the original model (2D transient model) and a numerical solution with spatial discretization of the radial direction through the method of lines (one-dimensional transient model) and then computationally implemented using the NDSolve subroutine of the numerical-symbolic computing platform Mathematica 13.0. Findings The velocity field slightly decreases in the stenosis region due to magnetic effects and reduced microrotation. Temperature rises locally from Joule heating. Fraction of nanoparticles (NPs) increases near the stenosis as reduced velocity enhances diffusion over convection. High NP concentrations appear near the injection site. Along the stenosis, NPs accumulate at the wall due to magnetic attraction. NP transport is primarily radial, from the center toward the wall. Streamlines converge in the stenosis, confirming accumulation. Magnetic field intensity and mean velocity have minimal influence. Higher NP death rates reduce NP presence, while low death rates allow pulsatile flow to enhance NP retention. Originality/value This study is highly important because of modeling blood as a micropolar fluid in which blood cells have their own rotational movement, using the Eringen micropolar fluid model (1966); modeling blood flow through injection, mass transfer and capture of MNPs by the action of the magnetic field in the stenosis region; considering the effects of thermophoresis and Brownian motion for blood flow with MNPs through the application of the Buongiorno nanofluid transport model (2006); and admitting the existence of a kinetic process of MNP death related to drug delivery to the target tissue.

The technique of numerical inversion of the Laplace transform is applied to solve the population balance equation (PBE). The model considers the dispersed phase systems in which nucleation and heterogeneous condensation are present. The studied phenomena model corresponds to a nonlinear integro-partial-differential equation. Test cases are solved considering two different collision mechanisms, the first-order removal mechanism and the effect of simultaneous coagulation and growth. Numerical results are compared with the analytical solution and with the literature. Based on these results, the technique applied in this work demonstrates to be a tool to solve problems in particulate systems, particularly for aerosol modeling where coagulation is the most important inter-particle mechanism affecting the size distribution.

The Piper hispidinervium leaves and thin stems were dried under laboratory and field conditions. Laboratory drying was performed using a shade dryer operating with and without forced convection and an oven dryer operating at 30 and 40 °C. Field experiments were conducted using solar dryers with three different covers, i.e., transparent, black plastic, and palm straw covers. The essential oil extraction was performed by steam distillation, and the safrole content was analyzed by gas chromatography. Five mathematical models (Page, logarithmic, Henderson and Pabis, fractional, and diffusion) were fitted with the experimental data and compared based on the coefficient of determination (R2), root mean square error (RMSE) and χ2. Results suggest that the best model was the logarithmic model (R2 > 0.99, RMSE < 0.000 5, and χ2 < 0.005). With sufficient drying, the safrole content increased up to 95% of the extracted oil; however, when the drying time was prolonged, both the oil yield and safrole content of the extracted oil decreased.

Hibiscus sabdariffa L. is a naturalized medicinal species in Brazil commonly called a “vinagreira” and is a member of the Malvaceae Juss. family, which has a rich potential of bioactive compounds presenting extracts with antioxidant, antibacterial, anti-inflammatory, hepatoprotective, antiviral, antidiabetic, and antiobesity, among others. The production of secondary metabolites of medicinal plants using biotechnological tools such as the culture of callus of plant tissues is increasingly being used to produce high-quality compounds under in vitro conditions. From this perspective, the objective of this work was to analyze the chemical compounds of the leaves and callus culture of H. sabdariffa using techniques of Gas Chromatography Coupled to the Mass Spectrum (GC-MS),. The analysis methodology used consisted of removal of liposoluble compounds, acid hydrolysis, and derivatization, all stages were submitted to ultrasonic-assisted agitation, using a reduced amount of biomass. Based on the results obtained in the study, a total of 38 metabolites identified by GC-MS analysis can be observed. Among the identified substances, protocatechuic acid (26A) stands out as the main constituent, with a relative abundance of 26.86% and 16.68% for leaves and callus of H. sabdariffa, respectively. The principal component analysis (PCA) allowed the discrimination of the chemical composition of each sample, being useful for the observation and detection of the compounds trends patterns. The analysis of the hierarchical group combined with the heat map represented the visual relationship between the samples of the data set indicating the values of higher and lower concentrations of chemical compounds respectively, confirming that protocatechuic acid is the most abundant, for the leaves and callus of H. sabdariffa, followed by eicosanoid and isocitric acid, produced only in callus. It was concluded that the GC-MS technique combined with chemometric tools, helped identify the diversity of the compounds present in the leaves and callus of H. sabdariffa and that callus culture enables the production of bioactive compounds continuously and uniformly in a controlled environment and free of contamination.

This study describes a comparative of the lipidomic profiles of the leaves of the species Crinum americanum L, Crinum jagus, Crinum erubescens, Hippeastrum puniceum and Hymenocallis littoralis belonging to the Amaryllidaceae family and the potential pharmaceutical metabolites applications. The extract obtained by ultrasound-assisted extraction with n-hexane was submitted to transesterification with MeOH/KOH and derivatization with BSTFA+1% of CSTS. It was applied analytical thin-layer chromatography with chemical reaction (ATLC-CR) and gas chromatography coupled to mass spectroscopy (GC/MS). To discriminate the similarities and differences between the researched species, a critical statistical analysis of the results was performed applying the Heatmap and principal component analysis (PCA) methodologies. The results indicated the presence of the following metabolic classes: monoacylglycerol (MAG), diacylglycerol (DAG), triacylglycerol (TAG), free fatty acids (AGL), steroids (ST), terpenes (TP), phospholipids (FL) and tocopherols (TF), and identify 50 metabolites in the samples, mainly saturated and unsaturated fatty acids and organic acids. Hexadecanoic acid is the major metabolite of all the investigated species, ranging from 16.00% to 23.44% of the extract's composition. The results of statistical analysis also reveal that the extracts from five Amaryllidaceae species have diverse metabolites with demonstrated the grouping between the same genera due to their lipid composition. (C) 2021 SAAB. Published by Elsevier B.V. All rights reserved.

In this paper, we analyze the transient magnetohydrodynamic (MHD) flow of an incompressible micropolar fluid between a porous parallel-plates channel. The fluid is electrically-conducting subjected to radiation described by the Cogley-Vincent-Gilles formulation and with convective thermal boundary conditions at the plates. The solution methodology employed is the hybrid numerical-analytical approach known as the Generalized Integral Transform Technique (GITT). The consistency of the integral transform method in handling such a class of problem is illustrated through convergence analyses, and the influence of physical parameters such as radiation, and micropolar parameters, and Hartman number. The wall shear stress, the coupled stress coefficient, and heat flux at the walls were also calculated, demonstrating that increasing the gyroviscosity decreases the wall stresses magnitudes. Furthermore, the results show that increasing the radiation heat transfer decreases the fluid temperature distribution. Additionally, the velocity is damped, and the angular velocity is increased by the Lorentz force in the presence of a magnetic field.

The generalized integral transform technique (GITT) is employed in the hybrid numerical-analytical solution of the two-dimensional Navier-Stokes and energy equations in wavy walls channels. The flow is considered laminar and incompressible for a Newtonian fluid with temperature-independent physical properties, while the walls temperatures are kept uniform along the channel length. The streamfunction-only formulation is adopted, which eliminates the pressure field and automatically satisfies the continuity equation. A thorough convergence analysis is performed for the streamfunction field, temperature field, friction factor, and local Nusselt number to illustrate the method robustness. The verification of the present GITT results is also performed by comparing the centerline velocity, friction factor, average temperature, and local Nusselt number with equivalent results from the COMSOL Multiphysics simulation platform, with overall very good agreement. The influence of the governing parameters such as Reynolds number and wavy-wall amplitude on the velocity and temperature fields is also analyzed, demonstrating their importance in the convective heat transfer behavior.

biofluido em um canal de placa paralela

The main goal of the present work is to show the procedure, application and main features of the hybrid numerical-analytical approach known as GITT (Generalized Integral Transform Technique) by solving an unsteady, one-dimensional magnetohydrodynamic (MHD) oscillatory flow of a micropolar and incompressible fluid with heat and mass transfer through a permeable vertical plate embedded in a porous medium in the presence of chemical reaction. The mathematical formulation of the studied model was obtained from the equation of motion and the mass and energy balances by considering laminar and incompressible flow subjected to a constant transverse magnetic field with constant physical properties. Convergence analysis was performed and presented to illustrate the consistency of the integral transform technique. Linear and angular velocities distribution, temperature and concentration profiles were generated and numerically verified with an approximate solution found in the literature and with the results of the method of lines (MOL) with good agreement. The effects of some governing parameters, namely, dimensionless time, magnetic field parameter, Schmidt and Prandtl numbers, permeability and chemical reaction parameters, on these fields were presented. The effects of these parameters on the local skin friction coefficient, the couple stress coefficient, the local Nusselt number and the local Sherwood number were also critically evaluated. Therefore, results show that the linear velocity decreases with increasing magnetic field parameter, while the angular velocity increases with increasing the same and the linear and angular velocities and the concentration field decrease as the Schmidt number increases while the temperature field decreases with increasing Prandtl number.

RESUMO – O presente trabalho busca aplicar a solucao hibrida da Tecnica da Transformada Integral Generalizada na solucao da equacao da conducao de calor em aletas longitudinais bidimensionais de perfil nao-variavel com condutividade termica dependente da temperatura com geracao de energia decaindo exponencialmente com a posicao caracterizando um problema nao-linear e nao-homogeneo. Para isso, foi utilizada a formulacao em termos de variaveis adimensionais com objetivo de simplificar o estudo do dominio da solucao, a partir do balanco de energia aplicado no volume de controle. Foram estudados dois casos limites para Biot tendendo a zero e infinito obtendo-se resultados semelhantes aos obtidos pela sub-rotina FPS2H da biblioteca ISML contida na linguagem de programacao cientifica Fortran 90/95.