Pseudo-conservation laws in cyclic-service systems with a class of limited service policies

This paper considers a cyclic-service system with a class of limited service policies that consists of exhaustive limited, gated limited and general decrementing policies. Under these policies, the number of customers served consecutively during a server visit is limited by a vector of integers. The major results in this paper are derivations of expected amount of work left in the queues at the server departures for these three policies. Exact expressions of weighted sum of mean waiting times, known as pseudo-conservation laws, are subsequently obtained. The conservation laws for this class of policies contain unknown boundary probabilities. We estimate these probabilities using corresponding server vacation models. Numerical results presented for the exhaustive limited policy are noted to be very accurate compared with simulation results. Moreover, we have obtained analytical bounds for the weighted sums. Finally, we present a conservation law with mixed service policies, and mean waiting times for symmetric systems.This work was completed while the author was in the Ph.D. program at Rensselaer Polytechnic Institute.This work was partially supported by the Center for Advanced Technologies of the New York State.     

Studies on uracils: A facile one‐pot synthesis of pyrazolo[3,4‐d]pyrimidines

The reaction of 6‐hydrazino uracils 1 and nitrones 2 result in an efficient one‐pot synthesis of pyrazolo[3,4‐d]pyrimidines 3 in excellent yields. The isolation of the by‐product aniline from the reaction mixture supported the plausible mechanism for the formation of pyrazolo[3,4‐d]pyrimidines.     

Bildungskonstanten von Komplexen der 3-Hydroxynaphthalin-2-carbonsäure mit Pr(III), Nd(III), Gd(III), Dy(III), Er(III) und Yb(III)

The stability constants of the complexes of 3-hydroxynaphthalene-2-carboxylic acid with some lanthanides have been obtained potentiometrically in aqueous dioxane (50%,V/V) at three temperatures and keeping the ionic strength at 0.1M (KNO₃), usingIrving-Rossotti titration technique. The values of overall changes in G°, H°, and S° have also been evaluated.     

Complexation reaction of metal ions with peptide systems. Part IV. A potentiometric study of rare earth complexes of glycyl-L-proline

Amino acids and dipeptides are of biological importance and therefore their metal complexes are of special interest. Many workers have studied the complexes of various peptides with different transition metals in solution^{1 – 5}. Although the stability of complexes of lanthanum with amino acids has been studied^{6 – 11}, no work appears to have been done with dipeptide systems. In continuation to our previous work^{12, 13} on the complexation reactions of lanthanides with dipeptide systems, the present communication reports the stability constants and thermodynamic functions of Y(III), La(III), Ce(III), Pr(III) and Nd(III) with glycyl-L-proline in aqueous medium at 25, 35 and 45°C at 0.15 M (KNO₃) ionic strength. The Calvin—Bjerrum titration technique^{14, 15} as modified by Irving and Rossotti¹⁶ was used.