Positive Magnetic Effect Research Articles

The effect of slip velocity on the ferrofluid based squeeze film in longitudinally rough conical plates

This article makes an attempt to study and analyze the effect of slip velocity on the performance of a magnetic fluid based squeeze film in conical plates considering the longitudinal roughness pattern. The slip model of Beavers and Joseph has been deployed to calculate the effect of slip velocity. The stochastic averaging model of Christensen and Tonder has been used to evaluate the longitudinal roughness effect. The concerned stochastically averaged Reynolds type equation is solved to get the pressure distribution which results in the calculation of load carrying capacity. The findings indicate that the combined adverse effect of slip velocity and roughness can be overcome to a large extent by the positive effect of magnetization and the standard deviation in the case of negatively skewed roughness. This effect further enhances when variance(-ve) is in place. A significant aspect of our study is that in spite of the adverse effect of slip velocity the rough bearing system sustains certain amount of load, even in the absence of the flow which is rarely seen in the case of traditional lubricant based conical bearing system.

Jenkins model based ferrofluid lubrication of a curved rough annular squeeze film: Effect of slip velocity

This paper analyzes the combined effect of slip velocity and transverse roughness on the performance of a Jenkins model based ferrofluid lubrication of a squeeze film in curved rough annular plates. The slip model of Beavers and Joseph has been invoked to evaluate the effect of slip velocity. In order to find the effect of surface roughness the stochastic averaging model of Christensen and Tonder has been used. The pressure distribution is obtained by solving the concerned stochastically averaged Reynolds type equation. The load carrying capacity is calculated. The graphical representations of the results indicate that the effect of transverse surface roughness is adverse in general, however, the situation is relatively better in the case of negatively skewed roughness. Further, Jenkins model based ferrofluid lubrication offers some measures in reducing the adverse effect of roughness when slip parameter is kept at reduced level with a suitable ratio of curvature parameters. Lastly, the positive effect of magnetization gets a boost due to the combined effect of variance (-ve) and negatively skewed roughness suitably choosing the aspect ratio.

Enlarging bulblet by magnetic and chelating structures of nano-chitosan as supplementary fertilizer in Lilium

The nutrition is the effective component on the increasing size of the bulb in growth period. In this work, carboxymethyl chitosan and magnetic nano-chitosan in a size ≤ 20 nm were synthesized that can be taken up by plant roots. The purpose of this work was to evaluate carboxymethyl chitosan and magnetic nano-chitosan with chelating structures as supplementary fertilizers to increase yearling bulblet growth in Lilium. The application of magnetic nano-chitosan at a concentration of 15 mg·L-1 as compared to its lower concentrations, carboxymethyl chitosan and iron sulphate had better effect on the promoting the growth, development and protecting the shoot, and growth of bulblet. Higher growth and development of shoots and roots by high concentration of magnetic nano-chitosan could affect the enlarging bulblet. There was a positive magnetic effect on the enzyme structures and supplying the essential iron for plant. Furthermore, magnetic nano-chitosan can act as a chelating component to facilitate the uptake of elements.

Theoretical study of Shliomis model based magnetic squeeze film in rough curved annular plates with assorted porous structures

In present theoretical investigation, the effect of Shliomis model based ferrofluid lubrication on the squeeze film between curved rough annular plates with comparison between two different porous structures is discussed. Kozeny-Carman's formulation and Irmay's model are adopted for porous structures. The stochastic models of Christensen and Tonder have been used for characterizing transverse roughness. The associated Reynolds type equation is solved to obtain the pressure distribution leading to the calculation of the load carrying capacity. The graphical representations show that the adverse effect of transverse roughness can be minimized by the positive effect of magnetization in the case of negatively skewed roughness, suitably choosing curvature parameters. Further, this compensation appears to be more in the case of Irmay's model as compared to that of Kozeny- Carman's method, which makes the Irmay's model more suitable for adoption. It is observed that the effect of morphology parameter and volume concentration parameter increases the load carrying capacity of the bearing system.

English

This article aims to analyze the performance of a magnetic-fluid-based porous rough step bearing considering slip velocity. The Neuringer-Rosensweig model governs the fluid flow while the velocity slip is modeled by the method of Beavers and Joseph. The bearing surfaces are assumed transversely rough and the transverse surface roughness of the bearing surfaces is characterized by a stochastic random variable with non-zero mean, variance, and skewness. With the usual assumptions of hydrodynamic lubrication, the related stochastically averaged Reynolds’ equation for the fluid pressure is solved with appropriate boundary conditions, which is then used to calculate the loadcarrying capacity. It is found that although the bearing suffers owing to transverse surface roughness, the performance of the bearing system can be improved to some extent by the positive effect of magnetization, considering the slip parameter at the minimum; at least in the case of negatively skewed roughness. A comparison of this paper with some established investigations indicates that here, the reduction of loadcarrying capacity due to porosity and slip velocity is comparatively less, especially, when negative variance occurs. In augmenting the performance of the bearing system, the step ratio plays a central role, even if the slip parameter is at the minimum.

Relations between terrestrial magnetism and cosmic‐ray intensity

Certain relations between the variations of the Earth's horizontal magnetic force H and of the observed cosmic‐ray ionization J have been found in the continuous registrations of the cosmic‐ray ionization on the Hafelekar, 2300 meters above sea‐level (near Innsbruck, Austria) during the year 1936–37 as follows:(1) A positive magnetic effect, ME1 is indicated during magnetic storms with increase of J associated with increase of H and vice versa. A similar effect has been noticed rather often also in the daily mean values of J and H during magnetically undisturbed days. ME1 amounts to +0.57 per mille of the cosmic‐ray ionization for an increase of the horizontal force by one γ (0.00001 gauss).(2) The analysis of the daily mean values for one year discloses a second effect, ME2, of opposite sign (increase of H accompanied by decrease of J) and smaller than ME1. ME2, for the average of the year 1936–37, is about −0.20 per mille per γ.(3) A similar negative magnetic effect, ME3, is found from the strong correlation between the diurnal variation of H and J; ME3= −0.2 per mille per γ.(4) Another negative effect, ME4, can be derived from the anti‐parallel variations of the monthly means of H and J (seasonal curves); ME4 = −1 per mille per γ.The three first‐mentioned effects can be explained qualitatively by adopting the hypothesis of the electronic ring‐currents in the outer space around the globe. The seasonal effect is not yet explained and it seems possible that its connection with terrestrial magnetism is accidental, in spite of the strong correlation.