Gravitational collapse in higher-dimensional charged-Vaidya space-time

We analyze here the gravitational collapse of higher-dimensional charged-Vaidya spacetime. We show that singularities arising in a charged null fluid in higher dimension are always naked violating at least strong cosmic censorship hypothesis (CCH), though not necessarily weak CCH. We show that earlier conclusions on the occurrence of naked singularities in four-dimensional case can be extended essentially in the same manner in 5D case also     

A single server queue in a hard-real-time environment

We consider a single server first in first out queue in which each arriving task has to be completed within a certain period of time (its deadline). More precisely, each arriving task has its own deadline - a non-negative real number - and as soon as the response time of one task exceeds its deadline, the whole system in considered to have failed. (In that sense the deadline is hard.) The main practical motivation for analyzing such queues comes from the need to evaluate mathematically the reliability of computer systems working with real time constraints (space or aircraft systems for instance). We shall therefore be mainly concerned with the analytical characterization of the transient behavior of such a queue in order to determine the probability of meeting all hard deadlines during a finite period of time (the ‘mission time’). The probabilistic methods for analyzing such systems are suggested by earlier work on impatience in telecommunication systems [1,2].     

Two queues with alternating service and server breakdown

We consider a queueing system with two stations served by a single server in a cyclic manner. We assume that at most one customer can be served at a station when the server arrives at the station. The system is subject to service interuption that arises from server breakdown. When a server breakdown occurs, the server must be repaired before service can resume. We obtain the approximate mean delay of customers in the system.     

Synthesis of organic-inorganic hybrid mesoporous tin oxophosphate in the presence of anionic surfactant

Synthesis of novel mesoporous hybrid tin oxophosphate is reported from phenylphosphonic acid as the only precursor of phosphorus in the presence of anionic surfactant (SDS), which possesses a wormhole mesoporous structure and is stable even after calcination at 550 degrees C.     

Convenient Synthesis of Novel Quinazoline Congeners via Copper Catalyzed C–N/C–S Coupling and Their Biological Evaluation

A library of novel quinazoline scaffolds endowed with semicarbazide/oxadiazole thiol motif synthesized via an efficient and sustainable copper catalyzed C–N/C–S coupling is reported, making the presented methodology extremely valuable from economic and environmental point of view. Among the all synthesized compounds screened for in vitro antibacterial, antifungal, and anti‐TB activity, 7b , 7c , 7f , 9b , 9c , 9i , and 9j showed excellent inhibitory effect on particular strain of bacteria, fungi, and M. tuberculosis H37Rv as well. All the newly synthesized derivatives were well characterized by their IR, ¹H NMR, ¹³C NMR, mass spectroscopy as well as elemental analysis.     

Highly efficient bio-sorption of trivalent f-elements using wild type Rhizopus arrhizus dead fungus

Journal of Radioanalytical and Nuclear Chemistry - Wild type Rhizopus arrhizus biomass was demonstrated as highly efficient bio-sorbent for trivalent f-elements. Both Am3+ and Eu3+ were found to...     

Recognition and Sensing of Guanidine-containing Biomolecules in Aqueous Medium

Russian Journal of Organic Chemistry - A dicarboxylate-based fluorescent receptor has been synthesized for the recognition of the guanidinium ion and guanidine-containing biomolecules in aqueous...     

Catalyst- and halogen-free regioselective Friedel-Crafts α-ketoacylations

Fast, efficient and green! Highly regioselective and efficient catalyst- and halogen-free Friedel-Crafts α-ketoacylation reactions leading to heterocycles functionalized with a very versatile 1,3-diketone moiety are described. The reactions rely on microwave-assisted domino Wolff rearrangement/Friedel-Crafts sequences from 2-diazo-1,3-diketones via transient, highly reactive α-keto ketene intermediates.