Self-similar analytical solutions for blast waves in inhomogeneous atmospheres with frozen-in-magnetic field

In the present paper, we have made an attempt to study the effects of the presence of a magnetic field on the cavity formation inside a blast wave propagating into a perfectly conducting gas with density varying as some power of distance from the plane or line of explosion. In order to obtain the closed form solutions for the flow variables inside the blast wave and to solve the problem of cavity formation analytically, a relation is taken between the ordinary pressure and the total pressure. It i s found that if the value of the inhomogeneity index is greater than a critical value (a function of M_A - Alfven Mach Number, - adiabatic index and i - wave geometry index), a contact discontinuity appears at some point inside the blast wave and the cavity formation occurs. The effect of the presence of magnetic field is found to increase the tendency of cavity formation.Received: 21 February 2003, Published online: 4 August 2003PACS: 47.40.-x Compressible flows; shock and detonation phenomena - 47.65.+a Magnetohydrodynamics and electrohydrodynamics     

Diluted tributyl phosphate as an extraetant for silver

Summary A new method is devised for the rapid solvent extraction of silver with diluted tributyl phosphate. Thus 40% TBP in butanol quantitatively extracts silver (49.8g) from 1M nitric acid that is 2M in lithium nitrate as salting-out agent. Silver is stripped with dilute ammonia and is determined photometrically at 495 ran as its red-violet complex withp-diethylaminobenzylidenerhodanine. The effect of acidity, varying TBP concentration and salting-out agent was studied. The probable composition of the extractable species is thought to be AgNO₃·(TBP)₃ or HAg(NO₃)₂(TBP)₃. Silver can be extracted in presence of a large number of elements with which it is associated in alloys, minerals or fission products. The method is simple, selective and rapid and needs only 30 minutes for the separation and determination.

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Zusammenfassung Eine neue Methode der Silberextraktion mit verd. Tributylphosphat (TBP) wurde angegeben. Mit 40% TBP in Butanol wird Silber (49,8g) aus 1-m Salpetersäure, die 2 Mole Lithiumnitrat pro Liter als Aussalzmittel enthält, quantitativ extrahiert. Das Silber wird dann mit verd. Ammoniak abgeschieden und photometrisch bei 495 nm als rotvioletter Komplex mit p-Diäthylbenzylidenrhodanin gemessen. Der Einfluß der Acidität, verschiedener TBP-Konzentration und des Augsalzmittels wurde untersucht. Die extrahierbare Verbindung hat wahrscheinlich die Zusammensetzung AgNO₃·(TBP)₃ oder HA_g(NO₃)₂(TBP)₃. Silber kann in Gegenwart vieler Elemente extrahiert werden, mit denen es in Legierungen, Mineralen oder Spaltprodukten vergesellschaftet ist. Das Verfahren ist einfach, selektiv und rasch. Für Trennung und Bestimmung sind 30 Minuten erforderlich.

     

On Extended Hermite-Fezér interpolation based on the zeros of Laguerre polynomials

Szász [2] proved the existence of an interpolatory polynomial which interpolates a given function at given data with some extended points. He also gave its explicit representation. We study the uniform convergence of the same, interpolating at the zeros of Laguerre polynomials with one point (as origin) extension.     

Effect of thermal conductivity on ultrasonic attenuation in praseodymium monochalcogenides

The ultrasonic attenuation in intermetallic praseodymium monochalcogenides are evaluated in the temperature interval 100–500 K along the crystallographic directions 〈100〉, 〈110〉, and 〈111〉 for longitudinal and shear waves. A comparison has been made with lanthanum monochalcogenides and other similar materials. Ultrasonic attenuation at different temperatures is mainly affected by the lattice thermal conductivity values of the materials at these temperatures. Thermoelastic loss is very small in comparison to the attenuation due to phonon-phonon interaction mechanism at higher temperatures.     

The Mossbauer effect on 119Sn nuclei in vanadium,platinum and niobium

The probabilities for recoilless resonant absorption of 23.8 keV γ-rays by ¹¹⁹Sn in matrices of vanadium, platinum and niobium have been calculated in the temperature ranges 80–400 K. The calculated results show a good agreement with the experimental data.     

Chaos control and function projective synchronization of fractional-order systems through the backstepping method

We study the chaos control and the function projective synchronization of a fractional-order T-system and Lorenz chaotic system using the backstepping method. Based on stability theory, we consider the condition for the local stability of nonlinear three-dimensional commensurate fractional-order system. Using the feedback control method, we control the chaos in the considered fractional-order T-system. We simulate the function projective synchronization between the fractional-order T-system and Lorenz system numerically using MATLAB and depict the results with plots.     

Glyceride‐Mimetic Prodrugs Incorporating Self‐Immolative Spacers Promote Lymphatic Transport,Avoid First‐Pass Metabolism,and Enhance Oral Bioavailability

First‐pass hepatic metabolism can significantly limit oral drug bioavailability. Drug transport from the intestine through the lymphatic system, rather than the portal vein, circumvents first‐pass metabolism. However, the majority of drugs do not have the requisite physicochemical properties to facilitate lymphatic access. Herein, we describe a prodrug strategy that promotes selective transport through the intestinal lymph vessels and subsequent release of drug in the systemic circulation, thereby enhancing oral bioavailability. Using testosterone (TST) as a model high first‐pass drug, glyceride‐mimetic prodrugs incorporating self‐immolative (SI) spacers, resulted in remarkable increases (up to 90‐fold) in TST plasma exposure when compared to the current commercial product testosterone undecanoate (TU). This approach opens new opportunities for the effective development of drugs where oral delivery is limited by first‐pass metabolism and provides a new avenue to enhance drug targeting to intestinal lymphoid tissue.     

Magnetised Strings in Λ-Dominated Anisotropic Universe

In this paper, we have searched the existence of Λ-dominated anisotropic universe filled with magnetized strings. The observed acceleration of universe has been explained by introducing a positive cosmological constant Λ in the Einstein’s field equation which is mathematically equivalent to dark energy with equation of state (EOS) parameter set equal to ?1. The present values of the matter and the dark energy parameters (Ω_m)₀ & (Ω_Λ)₀ are estimated for high red shift (.3 ≤ z ≤ 1.4) SN Ia supernova data’s of observed apparent magnitude along with their possible error taken from Union 2.1 compilation. It is found that the best fit value for (Ω_m)₀ & (Ω_Λ)₀ are 0.2920 & 0.7076 respectively which are in good agreement with recent astrophysical observations in the latest surveys like WMAP and Plank. Various physical parameters such as the matter and dark energy densities, the present age of the universe and the present value of deceleration parameter have been obtained on the basis of the values of (Ω_m)₀ & (Ω_Λ)₀.Also, we have estimated that the acceleration would have begun in the past at z = 0.6845 i. e. 6.2341 Gyrs before from now.