Highly Accurate Coiflet wavelet-Homotopy Solution of Jeffery-Hamel Problem at Extreme Parameters

The magnetised Jeffery-Hamel flow due to a point sink or source in convergent and divergent channels is studied. The simplified governing equation ruled by the Reynolds number, the Hartmann number and the divergent-convergent angle with appropriate boundary conditions are solved by the newly proposed Coiflet wavelet-homotopy method. Highly accurate solutions are obtained, whose accuracy is rigidly checked. As compared with the traditional homotopy analysis method, our proposed technique has higher computational efficiency and larger applicable range of physical parameters. Results show that our proposed technique is very convenient to handle strong nonlinear problems without special treatment. It is expected that this technique can be further applied to study complex nonlinear problems in science and engineering involving into extreme physical parameters. Besides, the influence of physically important quantities on the flow is discussed. It is found that wall stretching and shrinking exhibits totally different roles on the flow development. The enhanced Lorenz force affects the flow behaviours significantly for both convergent and divergent cases.

Impact of Cross-Diffusion on Methanol-Based Fe3O4 Nanofluid

This paper reports the impact of cross-diffusion on persistently moving a thin needle in a radiative hydromagnetic nanofluid flow. To validate the deviation in a border layer, we measured the flow features of two fluids such as methanol-magnetite and methanol. The converted ODEs are explicated by R-K centered shooting scheme. The consequences of extreme parameters on the existing profiles are depicted via graphs and numerical outcomes of tables. The study experiences that the velocity and temperature functions decrease with enhancing the needle size. The hypothesis of Soret and Dufour subjective to improve the thermal field, but it reduces the concentration. Further, it is noticed that the flow deterioration and strengthening of the thermal field have been perceived by the powers of Lorentz properties. The methanol-magnetite based nanofluid has higher thermal conductivity associated with methanol.

Appraisal of Main Extreme Parameters of Earthquakes in Nigeria Using the Weibull Equations

This study investigated earthquake occurrences in Nigeria using the Weibull equations. The data employed in this study was the historical and instrumental data recorded from 1933 to 2018. The relationship between intensity scale and Richter magnitude scale given by Gutenberg and Richter was used to convert from intensity scale to Richter scale. The Weibull equations were used to compute probabilities and return periods of earthquakes. The findings of the study revealed that the return period for an earthquake of magnitude 6.5 on Richter’s scale is 86 years; an earthquake of magnitude 4.7 is 34.4 years; an earthquake of magnitude 4.2 is 17.2 years and earthquake of magnitudes 2-3.7 is between 5.56-14.3years. This implies that Nigeria may not likely experience any earthquake of magnitude 6.5 till the year 2025 since earthquake of magnitude 6.5 last occurred in 1939 but the probability of occurrence is 1.16% or 0.0116. Earthquakes of highest magnitudes 6.5, 4.7 and 4.2 on Richter’s scale for a 100 year period which indicate the most hazardous in the location with probabilities exceedance of 1.16%, 2.91% and 4.65% were evaluated. It was observed that as the time increases the probability of occurrence of these earthquakes increases with it and vice versa with magnitude 4.2 having (99.1%), magnitude 4.7 having (94.8%) and magnitude 6.5 having (80.07%). But earthquake forecast or prediction is still a complicated issue due to saturation of earthquake magnitudes and variation in seismic data collection by different seismic stations and networks. The implication of this study is that the findings will help Nigeria government to protect its people, infrastructures and the constructions that are going to take place especially earthquake – prone areas like southwestern Nigeria.

Experimental Realization of an Extreme-Parameter Omnidirectional Cloak

An ideal transformation-based omnidirectional cloak always relies on metamaterials with extreme parameters, which were previously thought to be too difficult to realize. For such a reason, in previous experimental proposals of invisibility cloaks, the extreme parameters requirements are usually abandoned, leading to inherent scattering. Here, we report on the first experimental demonstration of an omnidirectional cloak that satisfies the extreme parameters requirement, which can hide objects in a homogenous background. Instead of using resonant metamaterials that usually involve unavoidable absorptive loss, the extreme parameters are achieved using a nonresonant metamaterial comprising arrays of subwavelength metallic channels manufactured with 3D metal printing technology. A high level transmission of electromagnetic wave propagating through the present omnidirectional cloak, as well as significant reduction of scattering field, is demonstrated both numerically and experimentally. Our work may also inspire experimental realizations of the other full-parameter omnidirectional optical devices such as concentrator, rotators, and optical illusion apparatuses.

Severe parasympathicotonia in men with hypertension is accompanied by an increase in the chronic venous diseases’ signs

Aim. To study the relationship of subjective and objective signs of chronic venous diseases (CVD) with the state of the autonomic nervous system (ANS) in men with arterial hypertension (AH).Material and methods. The object of the study were 74 men with AH at the age of 30-50 years with SBP level 148 (144-155) mm Hg. and DBP 101 (92-108) mm Hg. Two groups of 20 people were selected with the extreme parameters of vegetative index (Kerdo index).Results. The most common complaints in patients with severe parasympathicotonia were pain in the legs and fatigue when walking, cramps in the calf muscles, oedema and sural trophic disorders. An objective examination of patients with severe vagotonia revealed a more frequent occurrence of the leading symptom of CVD — oedema.Conclusion. AH with severe parasympathicotonia in men 30-50 years old is characterized by an increase in the frequency of subjective and objective signs of CVD, which indicates the role of ANS in the development of CVD in AH.

Combined electromachine generators for energy-efficient mini-power plants

The design, principle of operation and features of new combined electric machine – generator-transformer unit (GTU) are considered. The units are designed for generating units of mini thermal power plants with extreme parameters of moving media (steam-gas, gas-liquid, etc.) at high pressure and temperature. The possibility of reliable and efficient conversion of electric power by means of electric machines directly in sealed objects with extreme environmental conditions with help of new GTU is shown.