We present a study of residence time statistics for N renewal processes with a long tailed distribution of the waiting time. Such processes describe many nonequilibrium systems ranging from the intensity of N blinking quantum dots to the residence time of N Brownian particles. With numerical simulations and exact calculations, we show sharp transitions for a critical number of degrees of freedo...

the activation of carbon monoxide by oxygen on mg(100) surface has been investigated by x-ray photoelectron spectroscopy (xps). carbon monoxide is only weakly adsorbed (dispersion-type forces) on a magnesium surface. the xps result has shown that the dissociation of carbon monoxide leading to the formation of a metastable surface carbonate species occurs through the participation of an oxygen s...

In the core of Chemical Engineering is the reactor design that includes most of all scientific disciplines. The reactor, in general, are treated ideally: mixed and plug-flow patterns. Unfortunately, it is observed in the real world a very different behavior from that expected. Thus, to characterize nonideal reactors is used, among others, residence time distribution function E(t), mean residenc...

This paper shows that Danckwerts’ law for mean residence time in a vessel with continuous and steady throughflow holds for a stochastic model based on a Markov chain for the particle spatial position, under a set of three very general conditions on the transfer probabilities. These are natural conditions and represent mass balance conditions on the transfer between spatial regions in the proces...

Since the late 1950s, land reclamation from lakes has been a common human disturbance to ecosystems in China. It has greatly diminished the lake area, and altered natural ecological succession. However, little is known about its impact on the carbon (C) cycle. We conducted an experiment to examine the variations of chemical properties of dissolved organic matter (DOM) and C mineralization under...

AIM The aim was to assess the pharmacokinetic (PK) interaction of curcumin and glibenclamide (GL) in diabetic rats. MATERIALS AND METHODS Sprague-Dawley rats induced with diabetes were divided into 2 groups of six rats in each. Group I: GL (6 mg/kg po once daily) treatment in diabetic rats and group 2: Curcumin (50 mg/Kg po once daily) + GL (dose as above) in diabetic rats. Blood samples were...

The pharmacokinetic characteristics of cefepime were determined after first dose (n = 35) and again under steady-state conditions (n = 31) with a group of 37 infants and children. In eight subjects, a cefepime dose given by intramuscular injection was substituted for an intravenous dose, and disposition characteristics were studied again. Study subjects ranged in age from 2.1 months to 16.4 yea...

A 'first-passage-time' analysis is applied to enzyme kinetics. It is shown that the residence times determined in this way are directly related to the steady-state parameters and are particularly useful in analysis of isotopic exchange. A simple linear means is used for the calculation of these residence times that makes this method easily applicable to the numerical evaluation of complex model...

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