Numerical study on thermal performance of TiO2, Fe3O4 and NiCr/engine oil in an inclined wavy pip

The essential intention of the existing article is to illustrate the effect of wall properties on flow and thermal behavior, through a sinusoidal inclined wavy pipe. To succeed this phenomena we assume a sinusoidal pipe consist of wavy surface, whose walls traveling down to its borders and located at an inclined position, moreover titanium dioxide (TiO₂), ferrosoferric oxide (Fe₃O₄) and nichrome (80% Ni and 20% Cr) are considered as nano-particles and unused engine oil is assumed as a base fluid. The arising mathematical equations for thermal and flow ratio with wall slip impact are solved by mathematica. Also, evaluate graphically the thermal and flow behavior of nanofluids for multi values of solid volume fractions (η), rigidity parameter (M₁), stiffness parameter (M₂), viscous damping parameter (M₃), Grashof number (G_r), slip parameter (β) and heat generation parameter (H) also discuss the streamlines for different values of solid volume fraction.     

An experiment study on fluid heat and mass transfer properties in porous media using MRI

The objective of this study was to understand fluid heat and mass transfer processes in porous media with different pore structures. High-resolution Magnetic Resonance Imaging was used to measure fluid flow velocity and temperature maps in porous media. Firstly, three orthogonal velocity components (V _x , V _y , and V _z ) of single phase flow measurement were evaluated. The flow distribution in porous media is rather heterogeneous, and it is consistent with heterogeneous pore structure, and the velocity in large pore is high. Then we presented initial results from the extension of this work to two-phase flow. The CO₂ channeling phenomena were obvious. And the CO₂ velocity was calculated from saturation of water. Finally, the linearity relationship between temperature and the MRI parameter was determined for porous media, and we measured the temperature distribution of water saturated porous media. The study provides useful data for heat and mass process during CO₂ storage.     

Numerical treatment of Casson nanofluid Bioconvectional flow with heat transfer due to stretching cylinder/plate: Variable physical properties

PurposeThe purpose of the current framework is to scrutinize the two-dimensional flow and heat transfer of Casson nanofluid over cylinder/plate along with impacts of thermophoresis and Brownian motion effects. Also, the effects of exponential thermal sink/source, bioconvection, and motile microorganisms are taken.Methodology/ApproachThe resulting non-linear equations (PDEs) are reformed into nonlinear ODEs by using appropriate similarity variables. The resultant non-linear (ODEs) were numerically evaluated by the use of the Bvp4c package in the mathematical solver MATLAB.FindingsThe numerical and graphical illustration regarding outcomes represents the performance of flow-involved physical parameters on velocity, temperature, concentration, and microorganism profiles. Additionally, the skin friction coefficient, local Nusselt number, local Sherwood number, and local microorganism density number are computed numerically for the current presented system. We noted that the velocity profile diminishes for the rising estimations of magnetic and mixed convection parameters. The Prandtl number corresponds with the declining performance of the temperature profile observed. The enhancement in the values of the Solutal Biot number and Brownian motion parameter increased in the concentration profile.OriginalityIn specific, this framework focuses on the rising heat transfer of Casson nanofluid with bioconvection by using a shooting mathematical model. The novel approach of the presented study is the use of motile microorganisms with exponential thermal sink/source in a Casson nano-fluid through a cylinder/plate. A presented study performed first time in the author’s opinion. Understanding the flow characteristics and behaviors of these nanofluids is crucial for the scientific community in the developing subject of nanofluids.     

Modeling and computational framework of radiative hybrid nanofluid configured by a stretching surface subject to entropy generation: Using Keller box scheme

This study examines the characteristics of the velocity, thermal field and entropy profiles for hybrid nanofluid flow passing through a starching sheet with thermal radiation. The carbon nanotube (SWCNT and MWCNT) are used as a nanoparticles with Cattaneo-Christov (CC) heat flux. Ethylene glycol is utilized as a base fluid in this case. To achieve an improved solution, the fluid flow over the geometric properties is designed using highly non-linear PDEs, and the governing equations must be converted into dimensionless non-similar equation systems using the highly efficient well-known Keller-box scheme in computational software MATLAB. The practical feasibility of these solutions is determined by the range of the controlling parameters. The velocity distribution reduces as the magnetic parameter estimate increases, however, the temperature field and entropy production increase as the magnetic parameter fluctuation esclates. As the slip parameter is increased, the velocity field diminish. The thermal field is enhanced for rising the radiation parameter, and the entropy profile is boosted for increasing Brinkman parameter values. The findings of this research might have a significant impact on industries where local cooling and heating via impingement jets are needed in electronic devices, heat sinks, drying technologies, and so on. To the best of the authors' knowledge, this is the first effort to employ a hybrid nanofluid to analyze entropy formation due to magnetohydrodynamics flow over a starching sheet.     

A significant impact of Carreau Yasuda material near a zero velocity region

This goal of this study is to examine the incompressible steady 2D flow of MHD Carreau Yasuda model along with the heat generation and chemical reaction near a zero velocity region. The magnetic field and thermally conducting fluid towards a stretching cylinder are very significant due to its usage in the various manufacturing sector. Chemical reactions are widely practice in everyday life as turning nutrition into energy fuel for our body, food change, fireworks expulsions, removing grimes, photosynthesis, etc. The nonlinear flow model equations and their corresponding boundary conditions are changed into non-dimensional shape using similarity variables. The role of vital parameters is discussed with the assistance of MATLAB software by BVP4C method. It is concluded that the momentum increases for rising the curvature and stretching ratio parameter. This is examined that the heat field improves for rising behavior of the magnetic force, curvature coefficient and heat generation. The fluid concentration upsurges due to curvature and magnetic field parameter while reverse results shown due to chemical reaction parameter. We graphically investigate the impression of magnetic effect and chemical force for heat and mass profiles.     

Magnetohydrodynamic (MHD) flow of nanofluid with double stratification and slip conditions

This paper concerns with the analysis of double stratification in magnetohydrodynamic (MHD) flow of nanofluid by a stretching cylinder. Brownian motion and thermophoresis effects are present in the transport equations. The flow is subjected to velocity, thermal and solutal slip conditions. Non-linear ordinary differential equations are obtained from the governing non-linear partial differential equations after using appropriate transformations. The resulting non-linear ordinary differential equations are solved for the convergent series solutions. The velocity, temperature and concentration profiles are illustrated for different emerging parameters. Velocity distribution decays for higher estimation of velocity slip parameter. Furthermore, temperature decreases and concentration enhances for higher values of thermal stratification parameter and thermophoresis parameter, respectively. Numerical results for the skin friction, Nusselt number and Sherwood number are also presented and examined. Comparison between the published limiting solutions and present results is found in an excellent agreement.     

Peristaltic activity in blood flow of Casson nanoliquid with irreversibility aspects in vertical non-uniform channel

Due to the illuminating function of nanoliquids in several technological and medicinal domains, particularly in liquid transport processes known as peristalsis, inquisitive researchers have investigated the flow of peristaltic nanofluids. Consequently, the current study investigates the entropy production and magnetic influence on the peristaltic transport of heat and mass transport of Casson nanofluid in a non-uniform channel under convective circumstances. Utilizing the perturbation approach, fields of concentration, temperature, and velocity are derived from non-linear coupled partial differential equations (PDE). Entropy generation studies have been done. In addition, the influence of associated factors via specific physical terms, including the Sherwood number, the skin-friction coefficient, and the Nusselt number, for both Casson and Newtonian liquids, as well as the trapping phenomena, is visually examined.     

Microcalorimetric performance of the growth in culture of Escherichia coli,Proteus mirabilis and their mixtures in different proportions

Microcalorimetry is a technique that determines the heat flow produced as a result of microbial activities. The heat variations resulting from chemical reactions, which take place during metabolism, can be used to monitor bacterial growth in a culture medium. However, there are very few studies using calorimetry to investigate the relationships between two bacteria. In this work, we studied the interaction between E. coli and P. mirabilis, two bacteria belonging to the family Enterobacteriaceae. We have prepared three samples, mixing both enterobacteria at a concentration of 10³ CFU mL^?1 but in different proportions. Experimental equipment used was a Calvet microcalorimeter, where a constant temperature of 309.65 K was maintained. Then, we compared the shape of the heat flow–time curves of single microorganisms and their mixtures. Also, we calculated the thermokinetic parameters such as growth constant (k), generation time (G), detection time (t _d) and the amount of heat released (Q). The results obtained showed that when E. coli and P. mirabilis were put together in the culture medium, the growth profile of P. mirabilis seemed to dominate, even at low proportions in the sample.     

Computational modelling of radiative Maxwell fluid flow over a stretching sheet containing nanoparticles with chemical reaction

In the presence of thermal radiation, heat generation/absorption, and chemical reaction, the heat and mass transmission characteristics of a 2-D electrically conducting incompressible Maxwell fluid past a stretched sheet have been examined. There are various real-world applications for this issue, notably the extrusion of polymers and metal thinning. The transport equations take into account Brownian motion as well as thermophoresis when there is a chemical reaction involved. By making use of the relevant similarity variables, the PDEs that govern the stream and the boundary conditions that go along with them may be non-dimensionalized. The ensuing transformed ODEs are solved using the fourth- and fifth-order Runge-Kutta-Fehlberg scheme. It has been determined and quantitatively examined how the different embedded thermo-physical factors influence the velocity, temperature, and concentration. A case study comparison between our findings and those published in the literature reveals a high degree of agreement. Raising the value of the chemical reaction parameter causes a narrowing of the concentration distribution while increasing the temperature causes thermal radiation to have a greater impact. As the quantity of Nt increases, the thickness of the boundary layer grows, causing the surface temperature to increase, ensuing in a temperature increase.     

Propriétés viscoélastiques du poly(éthylène téréphtalate) en déformations homogène et plastique

The viscoelastic behaviour of poly(ethylene terephthalate) drawn at two temperatures, viz. 80 (homogenous drawing) and 20° (cold drawing), has been examined in order to characterize the influence of the thermomechanical history in the vicinity of the glass transition temperature T_g (transition α). Moreover, the shrinkage behaviour which is produced near T_g allows characterization of the elastic and viscous components which are developed through these two drawing processes.     

The effects of the spinodal microstructure on the electrical properties of TiO2-SnO2 ceramics

The electrical properties of ceramics within the TiO₂-SnO₂ system which exhibit spinodal decomposition were investigated under different annealing conditions. Changes in the lattice parameter and the phase evolution of the spinodal decomposition, measured in terms of the volume fraction transformed X(t), were examined as a function of annealing time using X-ray diffraction. The room temperature dielectric properties were measured and compared to dielectric mixing rules. Doping with pentavalent Nb was found to slow the decomposition kinetics and a high permittivity (ε_r>1000) was induced. The origin of the high permittivity is linked to the formation of an electrically heterogeneous structure which is derived from the spinodal microstructure. Lastly, it was observed that Nb-doped TiO₂-SnO₂ ceramics exhibited non-linear current-voltage behavior which can be attributed to the negative temperature coefficient of resistance effect.     

Solvent influence on the viscosity-temperature relationship for dilute polybutadiene solutions

The temperature dependence of the viscosity of dilute polybutadiene solutions has been described by an Arrhenius expression according to Moore's treatment. The activation energy of flow was found to depend on both concentration and molecular weight through an empirical parameter, K_e. This parameter was positive in toluene, zero in decalin and negative in dioxane. This behaviour is discussed in connection with the temperature dependence of the expansion coefficient (x_η) and the excluded volume parameter (z). A recent Yamakawa-Tanaka expression relating x_η and z was used in the theoretical calculation of K_e.     

PVC/MMT nanocomposites

Poly(vinyl chloride) (PVC) nanocomposites with sodium montmorillonite (Na-MMT) and organically modified MMT (O-MMT) have been prepared by melt processing using mixing and extrusion techniques. The differential scanning calorimetry (DSC) with stochastic temperature modulation (TOPEM?) results show that the glass transition temperature (T _g) of PVC is slightly higher than T _g of PVC/Na-MMT and PVC/O-MMT which would indicate that MMT plays a role of an internal plasticizer that increases the distance between the PVC macrochains. The DSC TOPEM non-reversing heat flow profiles show enthalpy relaxation effects, and the lowest value has been found for pristine PVC—the presence of MMT (both Na+ and ammonium salt modified) may generate a certain orientation level of PVC macrochains during the extrusion process. Specific heat vs temperature dependencies at different frequencies revealed that the best fit to the single profile was found for PVC/Na-MMT nanocomposite, and this observation may be related to internal stability of the composite material as confirmed by analysis of the change in the specific heat (Δc _p).     

Heat transfer analysis of tangent hyperbolic nanofluid in a ciliated tube with entropy generation

In this paper, we analyze the effect of heat transfer on the flow of tangent hyperbolic nanofluid in a ciliated tube (fallopian tube where embryo in blood make the development). This study will be beneficial for the researchers and medical experts in the field of embryology. The nanoparticles are beneficial to remove the cysts from the fallopian tube where development of embryo takes place. To resolves the ciliary flow problems, medical doctors use nanoparticles (drug delivery) that may create a temperature gradient. The heat transfer helps to optimize the energy for which the entropy generation is reduced. Therefore, in this research we discuss the heat transfer effect on tangent hyperbolic nanofluid and entropy generation due to ciliary movement. The governing partial differential equations are solved by HPM and software MATHEMATICA?. Effect of viscoelastic parameter, nanoparticles, cilia length and Brinkman number on the velocity, temperature and entropy generation has been illustrated with the help of graphs. Graphical results show that thermal conductivity of fluid increases by adding nanoparticles. The entropy generation due to nanoparticles will decrease the viscosity near the tube wall and blood through tube will flow with normal pressure.

     

A study of heat and mass transfer of Non-Newtonian fluid with surface chemical reaction

Considering the significance of non-Newtonian fluid usage in manufacturing such as molten plastics, polymeric materials, pulps, and so on, significant efforts have been made to investigate the phenomenon of non-Newtonian fluids. In this article the influences of heat and mass transfer on non-Newtonian Walter's B fluid flow over uppermost catalytic surface of a paraboloid is encountered. An elasticity of the fluid layer is considered in the freestream together with heat source/sink and has the tendency to cause heat flow in the fluid saturated domain. The flow problem of two-dimensional Walter's B fluid is represented using Law of conservation of mass, momentum, heat, and concentration along with thermal and solutal chemical reactive boundary conditions. The governing equations are non-linear partial differential equation and are non-dimensionalized by employing stream function and similarity transformation. The final dimensionless equations yielded are coupled non-linear ordinary differential equations. Furthermore, shooting technique along with RK-4th order method is used to get the numerical results. Graphs and tables are modeled by using MATLAB software to check the effects of Walter's B parameter, Chemical reaction parameter and Thickness parameter on temperature, velocity, and concentration profiles. Tabular analysis shows the results of some physical parameters like skin friction coefficient, Nusselt number and Sherwood number due to the variation of Walter's B parameter, thickness parameter and chemical reactive parameter.     

Estimation of Particle Capture Zone Characteristics in Magnetic Filtration Processes

The real properties of the geometry of the capture region of the particles in the pores of the magnetic filters which are formed by magnetized ferromagnetic microparticles are investigated. The flow velocity profile of the liquid in this region is determined and the effect of the velocity profile to keep the particles in the pores is examined. The magnetic and the hydrodynamic powers have been expressed explicitly by considering, the pore geometry, magnetized property and the flow velocity. Obtained expression was explained on the V _m /V _f ratio, which is named as magnetic and flow velocities rate in filtering and separation processes. According to this expression, the volume and surface ratios of the particles which are accumulated in the particles capture region are taken into account. From theory and practice point of view, the derived expressions and results are put into a form to make easy to use for design, control and optimization of the filters.     

A new approach to the determination of column overload characteristics in reversed-phase liquid chromatography

Column overloading is very common during the separations of basic analytes in analytical scale reversed-phase liquid chromatography (RPLC). Due to the complex interactions of ionic analytes with stationary and mobile phases, only a very small amount of ionized sample compared to the amount of nonpolar solute can be injected before the peak shape is distorted by non-linear chromatographic processes. Often the amount that can be injected before overload is observed is so small that the signal is quite noisy, thereby making the measured plate count imprecise and possibly inaccurate. The purpose of the present study was to develop a practical method for the precise measurement of the plate count and a column overload parameter using a simple but mathematically rigorous model of Langmuirian non-linear chromatography. An “overload profile”, i.e. a plot of apparent plate count versus amount injected, is characterized by two parameters: the limiting plate count (N₀) and the column sample loading capacity (ω_0.5). The limiting plate count is the plate count that should be observed when the amount of sample injected is so small that a linear isotherm pertains. The column sample loading capacity, which is taken as the sample load that leads to a plate count equal to half of the limiting plate count, is a measure of the maximum amount of sample that can be injected into that column. The approach was tested by applying it to the study of cationic analytes in RPLC. We show that N₀ under constant conditions (column length, flow rate, mobile phase composition, etc.) is almost independent of column type (manufacturer); however, different column types (at the same length, diameter and flow rate) exhibit clear differences in their sample loading capacity (ω_0.5). We believe that for most well packed type B columns, the column sample loading capacity and not the limiting plate count is the more important property that accounts for most of the apparent differences in peak width when different types of columns are examined.     

The use of DSC to determine the Curie temperature of metallic glasses

The subject of metallic glasses is introduced. These materials have technological potential, but only if their stability is adequate. It is, therefore, important to study their transformations on annealing, especially structural relaxation. The ferromagnetic Curie temperature, T_c, is a particularly useful parameter for monitoring structural relaxation and it can be measured by differential scanning calorimetry (DSC). The DSC method is convenient and accurate if temperature lags are corrected for. Ways of performing this correction in the DuPont DSC system are reviewed and a new method is proposed and tested. The experimental details of determining the T_c of metallic glasses are given. Finally, the relaxation behaviour of Fe₈₀B₂₀ glass, as studied by measuring its T_c, is reviewed. This behaviour is similar to that of conventional oxide glasses.     

Experimental design for copper cementation process in fixed bed reactor using two-level factorial design

This work deals with cementation of copper onto iron grid in a fixed bed reactor. The influence of several parameters is studied, namely: initial concentration of copper [Cu²⁺]₀, temperature and flow rate. Moreover, their influence on the copper cementation reaction is investigated statistically by the experimental design in view of industrial application. The estimation and the comparison of the parameter’s effects are realized by using two-level factorial design. The analysis of these effects permits to state that the most influential factor is initial concentration of copper [Cu²⁺]₀ with an effect of (+2.4566), the second in the order is the temperature with an effect of (+0.18959), the third is the flow rate of the electrolytic solution with an effect of (?0.4226). The significance interactions found by the design of experiments are between initial concentrations of copper ions–flow rate (x₁x₃) with an effect (b₁₃ = +0.6965).     

Excess heat capacities of binary mixtures of carbon tetrachloride with n-alkanes at 298.15 K

A Picker flow microcalorimeter was used to determine molar excess heat capacities C_P^E at 298.15 K for mixtures of carbon tetrachloride + n-heptane, n-nonane, and n-decane. The excess heat capacities are negative in all cases. The absolute value |C_P^E| increases with increasing chain length of the alkane. A formal interchange parameter, c_P12, is calculated and its dependence on n-alkane chain length is discussed briefly in terms of molecular orientations.