Effects Of Different Physical Factors Research Articles

Thermophoresis & Soret-DuFour on MHD Mixed Convection of a Nano Fluid with a Porous Medium over a Stretching Sheet with a Non-Uniform Heat Source/Sink

This work aimed to examine the effects of thermal diffusion (Soret) and diffusion-thermo (DuFour) on MHD mixed convective flow of a viscous nanofluid across a stretching sheet under a magnetic field embedded in a porous medium in the presence of non-uniform heat source/sink and chemical reaction. The governing equations are transformed into a set of ordinary differential equations using the similarity transformation approach. They are subsequently resolved computationally by use of the efficient Keller box method. The effects of different physical factors on concentration, temperature, and velocity profiles are graphically shown. Increasing Du values decreases temperature, although concentration profiles indicate the reverse. As temperature rises, the chemical reaction parameter Kr values increase, while the concentration profile decreases. The temperature was found to rise when the space-dependent (A1) and temperature-dependent (B1) parameters for heat source/sink increased. Additionally, a tabular presentation of the skin friction coefficient, Nusselt number, and Sherwood number behaviour is provided. Mixed convection heat and mass transfer flows are very important in manufacturing for designing reliable equipment, nuclear power plants, gas turbines, and various propulsion devices for aircraft, rockets, satellites, and spacecraft. The effects of non-uniform heat sources/sinks, thermophoresis, and chemical reactions on mixed convection flow play an important role in space technology and high-temperature processes.

INTELLIGENT NUMERICAL METHOD FOR STUDYING MAXWELL WILLIAMSON NANOFLUID FLOW WITH ACTIVATION ENERGY

The use of artificial intelligence and its techniques has become increasingly widespread in recent times. It is being used to solve stiff non-linear equations. Additionally, nanofluids play a pivotal role in studying heat transfer. All of this was the motivation for doing this work. This work investigates a two-dimensional magnetohydrodynamic stretched flow (2D-MHDSF) of Maxwell Williamson nanofluid (MWNF) affected by bioconvection and activation energy numerically through Levenberg-Marquardt backpropagation method (LMBM)-based artificial neural network approach. The mathematical formulation for the problem was obtained through non-linear partial differential equations (PDEs). The leading PDEs were transmitted into non-linear ordinary differential equations by similarity transformation variables. The reference results for the 2D-MHDSF-MWNF model are produced by the Lobatto IIIA method through different scenarios of specific parameters for the flow velocity, fluid temperature, nanoparticle concentration, and motile density profiles. Using obtained results as a dataset to apply the testing, training, and validation steps of the suggested LMBM for the 2D-MHDSF-MWNF model. The mean squared error, analysis of regression, and error histograms are presented to prove the efficiency and precision of the proposed method. The numerical results of LMBM are displayed as a study of the effects of different physical factors on flow dynamics for 2D-MHDSF-MWNF.

Effect of extraction conditions on obtaining pectin from agroindustrial coffee by-products

To present a proposal to reduce the waste generated in coffee agroindustrial production and explore potential applications of by-products, this study presents the effects of different physical factors (pH, temperature, and reflux time) on the extraction of pectin from coffee husks Coffea arabica, discarded in coffee farms of San Juan de Rioseco area after the desiccation process. The extraction is carried out by hydrolysis in an acidic medium using hydrochloric acid, precipitation by coagulation with 96% ethanol, filtration, and subsequent drying at 45 °C. Finally, the quality of the pectin obtained is evaluated by infrared spectrophotometry to determine the degree of esterification as well as the yield of the extractions carried out under different conditions. High methoxyl pectins, between 56% and 75% of esterification and yields that do not exceed 1% are obtained from wet material. An inverse temperature-degree of the esterification relationship and a direct time-yield relationship was found, according to an analysis of the main components and surface graphs, finding that the best extraction conditions are pH 2.0, temperature 90 ° C after 1 hour. The results suggest that byproducts from the coffee agro-industrial process are a promising source of pectin.

Effects of different physical factors on potato protein-chitosan complexes considering Hofmeister series and Maillard reaction.

Potato protein possesses strong potential for application in the food industry due to its outstanding nutritional and functional properties. However, the inevitable industrial processing often brings adverse effects. The use of a polysaccharide and protein complex is a promising way to improve the performance of potato protein. This work aimed to investigate the effects of different physical factors on the potato protein/chitosan (PP/CS) complex system. The addition of NaCl was not conductive to the formation of PP/CS complexes, resulting in significantly decreased peak turbidities from 1.29 to 0.75. The effect of different ions on PP/CS system matched with the Hofmeister series in the following order: Li+ > Control > Na+ > K+ ; SCN- > I- > NO3 - > Br- ≈ Control > Cl- > SO4 2- , among which the salting-in ions (Li+ , Br- , NO3 - , I- and SCN- ) tended to promote the formation of PP/CS complexes. The turbidity increased significantly when the reaction temperature rose to 45 °C and above, and peak turbidity was obtained at lower pH values. The PP/CS system reaction at 45 °C led to the highest whiteness value, and the Maillard reaction could occur when the temperature was above 45 °C. The results of the present study confirmed that different physical factors led to strong influences on PP/CS complexes, especially when considering the Hofmeister series and the Maillard reaction. These findings could have significant implications for the utilization of potato protein in complex food systems. © 2023 Society of Chemical Industry.

Effect of different physical factors on the synthesis of spherical gold nanoparticles towards cost-effective biomedical applications.

Gold nanoparticles (AuNPs) have great potential to contribute to numerous application fields of biomedicine, which are highly dependent on their physicochemical properties, such as size and shape. Due to the final characteristics, nanoparticles (NPs) are primarily affected by different factors of reaction conditions; the present study aimed to evaluate the effects of manipulating the main physical parameters of the Turkevich method to optimise the fabrication of citrated capped AuNPs in a spherical shape, desirable final size, and efficiency. For this purpose, various experiments of citrate-capped spherical AuNPs synthesis were designed to study the roles of a wide range of initial pH values and temperature of reaction, Na3 Cit/HAuCl4 molar ratio, and two order reagent additions, method I and method II, in the final characterisations and reaction efficacy. Prepared NPs synthesised with different experiments were characterised by dynamic light scattering, UV-Visible, and fourier transform infrared spectroscopy. Furthermore, NPs obtained from optimised synthesis conditions were more detailed using UV-Visible, transmission electron microscopy, and XRD. The findings indicated that the final size and synthesis efficacy of citrated capped spherical AuNPs were significantly affected by all studied synthesis parameters and the order addition of reagents. The higher initial reaction temperature and Na3 Cit/HAuCl4 Molar ratio provided a smaller particle size with desirable synthesis efficacy. Besides, final optimised NPs were provided in cubic crystal structures, and each NP's single crystal was obtained. In sum, our findings indicated that optimising synthesis conditions could improve size distribution, morphology, crystallite size, and structures of final NPS, as well as efficiency, which is a principal factor associated with future cost-effective productions on large scales. Further studies are needed in this regard.

Impact of physical factors on bio-control potential of Lawsonia inermis leaf extract and bio-formulations as fungicides

The present study is carried out to ascertain the effect of different physical factors (sunlight, temperature, pH) and storage conditions on the antimicrobial efficacy of Lawsonia inermis leaf extracts and bio-formulation against the Alternaria alternata. In addition, the phytotoxic potential of 100% alcoholic crude extract as well as the acetone fraction of young leaves of Lawsonia inermis was also checked on seed germination of chilli (Capsicum annuum). Results showed that there was no adverse effect of wet heat (50–100 °C) and dry heat (40–90 °C) on extract and bio-formulation efficacy. Storage for 6 and 12 months had no adverse effect on extract and bio-formulation efficacy and the antifungal activity was observed similar to freshly prepared extract. We have used concentrations of 5,10, 15, 20 and 25 mg/ml to perform a phytotoxicity assay. The measurement of phytotoxicity was done by using the Standard blotter method and the result revealed that 5, 10 and 15 mg/ml concentration of the extract was non phytotoxic and were further used for in vivo experiments. These plant extracts and bio-formulations have extensive antimicrobial potential to be explored for application in sustainable agriculture.

Effect of Different Physical Factors on efficacy of Thevetia Peruviana leaf extract and bio-formulations

Plant extract possess various secondary metabolites which are antifungal in nature and can be used as a safer alternative to the synthetic fungicides. As we all know that the chemical fungicides are harmful not only for humans but also for animals, other vegetation and for complete ecosystem. To overcome this problem, we have to focused on another alternative which are biologically libel and nonhazardous also. In the present study, herbal formulation was prepared in various combination ratios with Thevetia peruviana leaf extracts, cow dung and neem oil cake. The major aim of this short study is to check the stability of the said plant extracts and prepared herbal formulation on various physical factors like heat, temperature, pH, sunlight and storage etc. The extracts and herbal formulations were exposed to varying conditions of the parameters selected for a precise time period, and then observing the effect as a function of change in the crude extract activity, herbal formulation activity and change minimum inhibitory concentration of plant extract against the Alternaria solani. Control set of MIC, and extract free medium were maintained for comparison in each set of experiment against Alternaria solani. Results suggested that efficacy of leaf extracts and different formulations was not affected by wet heat up to 100 °C while slight reduction in antifungal activity of the plant extract and herbal formulations were observed with dry heat at 100 °C. In addition, slight reduction in activity of extract and herbal formulations was observed with change in pH. However antifungal activity of plant extract as well as herbal formulations, remain unaffected at alkaline pH (pH 9) and neutral pH (pH7). Storage for 6 and 12 months had no negative effect on extract and herbal formulation efficacy and the antifungal activity was observed similar to freshly prepared extract activity. The present study concluded that the plant disease or plant pathogens can be controlled by plant extract and plant based bioformulations by increasing the shelf life with some little changes in the physical parameters such as light, temperature, pH and storage.

Coherent structures of nonlinear barotropic-baroclinic interaction in unequal depth two-layer model

The nonlinear barotropic-baroclinic interaction theory is of great importance for the understanding of the atmosphere and the oceans. In this paper, a mathematical model based on analytical methods is established to discuss the propagation of the coherent structure of the nonlinear barotropic-baroclinic interaction of two-layer fluids in geophysics. It is the first time that the coupled Boussinesq equations are derived by using perturbation and spatiotemporal extensions transformations to simulate the evolutions of nonlinear barotropic and baroclinic waves. The solitary wave solutions are analytically obtained to explain the excitation, propagation and decrease of the coherent structures. The physical mechanism of the nonlinear wave-wave coherent structures is discussed by considering the effects of different physical factors, such as the topography, the Earth’s rotation and the basic shear flow. It is found that both topography and beta parameter have essential effects on the evolutions of the coherent structures. Furthermore, the effect of the unequal-depth parameter on the propagation of coherent structures is discussed.

Dynamic characteristics and stability of pipe-in-pipe system conveying two-phase flow in thermal environment

Pipe-in-pipe (PIP) systems are utilized widely in modern petroleum industry owing to their good insulation effect. In present work, a novel mathematical model for the free vibration of the fluid-conveying cantilevered PIP system considering thermal effect and two-phase flow is proposed. The insulation layer connecting two concentric pipes is simplified as the distributed springs and dampers here. The governing equation of the pipe system is then derived using Hamilton's principle based on Euler-Bernoulli beam theory. Then the Galerkin method is applied to the free vibration analysis. In the numerical section, parametric analysis is performed to elucidate the effects of different physical factors, such as environment temperature, equivalent stiffness and damper of the insulation layer, structural damping, two-phase flow, and axial load on the dynamic characteristic and stability of the PIP system through the forms of Argand diagram, stability map, and time history diagram. The results show that the PIP system has an advantage over a single fluid-conveying pipe in terms of stability considering thermal effect, axial load, and structural damping. Besides, different from single pipe, two different frequencies are found for each vibration mode, and two-pipe coupled flutter instability occurs to the PIP system as the fluid velocity exceeds the critical fluid velocity. The theoretical work is helpful to improve the analysis and design of the PIP system with consideration of internal two-phase flow and environmental temperature.

The Effects of Low Doses of Gamma-Radiation on Growth and Membrane Activity of Pseudomonas aeruginosa GRP3 and Escherichia coli M17.

Microorganisms are part of the natural environments and reflect the effects of different physical factors of surrounding environment, such as gamma (γ) radiation. This work was devoted to the study of the influence of low doses of γ radiation with the intensity of 2.56 μW (m2 s)-1 (absorbed doses were 3.8 mGy for the radiation of 15 min and 7.2 mGy-for 30 min) on Escherichia coli M-17 and Pseudomonas aeruginosa GRP3 wild type cells. The changes of bacterial, growth, survival, morphology, and membrane activity had been studied after γ irradiation. Verified microbiological (specific growth rate, lag phase duration, colony-forming units (CFU) number, and light microscopy digital image analysis), biochemical (ATPase activity of bacterial membrane vesicles), and biophysical (H+ fluxes throughout cytoplasmic membrane of bacteria) methods were used for assessment of radiation implications on bacteria. It was shown that growth specific rate, lag phase duration and CFU number of these bacteria were lowered after irradiation, and average cell surface area was decreased too. Moreover ion fluxes of bacteria were changed: for P. aeruginosa they were decreased and for E. coli-increased. The N,N'-dicyclohexylcarbodiimide (DCCD) sensitive fluxes were also changed which were indicative for the membrane-associated F0F1-ATPase enzyme. ATPase activity of irradiated membrane vesicles was decreased for P. aeruginosa and stimulated for E. coli. Furthermore, DCCD sensitive ATPase activity was also changed. The results obtained suggest that these bacteria especially, P. aeruginosa are sensitive to γ radiation and might be used for developing new monitoring methods for estimating environmental changes after γ irradiation.

Hydrogen production by reaction of aluminum with water

The hydrogen production by reaction of aluminum foils and powders with KOH aqueous alkaline solutions was studied. Effect of different physical factors on the specific hydrogen production rate was analyzed. The efficiency of activation of aluminum by copper was examined. Three variants of contacting copper with aluminum were considered: 1) preliminary chemical coating of the aluminum surface, 2) embedding copper into the melt of aluminum or pressing the aluminum – copper powder mixture, 3) continuous supplying copper to the aluminum surface during the reaction.The results showed that presence of copper on the surface or in the bulk of aluminum essentially increased the effective hydrogen production rate. The filtration corrosion in pressed aluminum powder was found.Hydrogen production at reaction of aluminum with NaCl + CuSO4 solutions was studied.

PHONON TRANSPORT AND THERMAL CONDUCTIVITY IN TWO-DIMENSIONAL MATERIALS

Two-dimensional materials, such as graphene, boron nitride and transition metal dichalcogenides, have attracted increased interest due to their potential applications in electronics and optoelectronics. Thermal transport in two-dimensional materials could be quite different from three-dimensional bulk materials. This article reviews the progress on experimental measurements and theoretical modeling of phonon transport and thermal conductivity in two-dimensional materials. We focus our review on a few typical two-dimensional materials, including graphene, boron nitride, silicene, transition metal dichalcogenides, and black phosphorus. The effects of different physical factors, such as sample size, strain and defects, on thermal transport in Two-dimensional materials are summarized. We also discuss the environmental effect on the thermal transport of two-dimensional materials, such as substrate and when two-dimensional materials are presented in heterostructures and intercalated with inorganic components or organic molecules.

Stability analysis of axial reflection symmetric spacetime

In this paper, we explore instability regions of non-static axial reflection symmetric spacetime with anisotropic source in the interior. We impose linear perturbation on the Einstein field equations and dynamical equations to establish the collapse equation. The effects of different physical factors like energy density and anisotropic stresses on the instability regions are studied under Newtonian and post-Newtonian limits. We conclude that stiffness parameter has a significant role in this analysis while the reflection terms increase instability ranges of non-static axial collapse.

Interactive effects of temperature and salinity on population dynamics of the calanoid copepod Acartia tonsa

The euryhaline, eurytherm copepod Acartia tonsa plays a key role in many marine food webs as a grazer on phytoplankton and as prey species for commercially important planktivorous fishes. The different populations of this cosmopolitan species experience a wide range of environmental conditions. This study aims to elucidate the response of A. tonsa to changes in multiple environmental factors. The effects of temperature (T), salinity (S) and the interaction of both variables on recruitment processes were investigated to show potential influences of changes in environmental conditions on its life cycle and population dynamics. Estuarine conditions appeared to be optimal for reproduction, despite the marine origin of the population. Interactive effects of T × S were more pronounced when the population was exposed for a longer period of time to constant laboratory conditions. Potential resting eggs were identified based on morphology and hatching characteristics, and were mainly produced at high S and low T. Our results emphasize the importance of investigating the combined effects of different physical factors to gain a better understanding of potential changes in population dynamics resulting from climate-induced changes in key environmental factors.

The effects of physical factors on the quality of the dual high-energy identification of the material of an inspected object

A significance criterion was formulated for the effect of physical factors on the quality of the dual high-energy identification of the material of an inspected object. Some recommendations on its practical application are given. A series of calculations on the estimation of the effects of different physical factors on the quality of identification was performed for an MIB 4.5/7.5 small commercially produced betatron. The considered factors were the deviation of the maximum energy high-energy X-rays from the nominal values, the radiation scattered in an inspected object, and the radiation scattered in the structure of a customs inspection complex. These studies proved the necessity of taking the considered factors into account in the design of customs inspection complexes with the possibility of the dual high-energy identification of the material of an inspected object and its fragments.

Detection of Cr6+ by the Sulfur Oxidizing Bacteria Biosensor: Effect of Different Physical Factors

A biosensor based on sulfur-oxidizing bacteria (SOB) for detection of toxic chemicals in water was developed. SOB are acidophilic microorganisms that get their energy through the oxidation of reduced sulfur compounds in the presence of oxygen to produce sulfuric acid. The reaction results in an increase in electrical conductivity (EC) and a decrease in pH. The bioassay is based on the inhibition of SOB in the presence of toxic chemicals by measuring changes in EC and pH. The effect of different physical factors such as HRT, inorganic sulfur (S°) particle size, and temperature on detection of Cr(6+) was studied. The detection of Cr(6+) (50 ppb) was improved by decreasing the hydraulic retention time (HRT) from 30 to 10 min and increasing S° particle size from 1 to 4.75 mm. Detection time was shorter at 30 °C compared to 45 °C and the SOB were active over a wide range of temperatures with a maximum temperature for growth at 45 °C. This novel biosensor is simple, highly sensitive to low Cr(6+) concentrations (50 ppb), and also minimizes detection time. The present findings can be applied to the proper continuous screening of water ecosystem toxicity.

Modeling Bidirectional Texture Functions with Multivariate Spherical Radial Basis Functions

This paper presents a novel parametric representation for bidirectional texture functions. Our method mainly relies on two original techniques, namely, multivariate spherical radial basis functions (SRBFs) and optimized parameterization. First, since the surface appearance of a real-world object is frequently a mixed effect of different physical factors, the proposed sum-of-products model based on multivariate SRBFs especially provides an intrinsic and efficient representation for heterogenous materials. Second, optimized parameterization particularly aims at overcoming the major disadvantage of traditional fixed parameterization. By using a parametric model to account for variable transformations, the parameterization process can be tightly integrated with multivariate SRBFs into a unified framework. Finally, a hierarchical fitting algorithm for bidirectional texture functions is developed to exploit spatial coherence and reduce computational cost. Our experimental results further reveal that the proposed representation can easily achieve high-quality approximation and real-time rendering performance.

Natural convection of an electrically conducting fluid in a spherical layer. 1. Formulation of the problem

Natural-convection heat transfer of an electrically conducting fluid in a spherical layer modeling the earth’s liquid core is considered. The effect of different physical factors on fluid flow in a spherical interlayer is analyzed.