Laminar and turbulent mass transfer simulations in a parallel plate reactor

Laminar and turbulent mass transfer in a parallel plate reactor at high Schmidt number obtained from numerical simulation is compared with literature data. In a first step, the fluid flow is determined numerically in the reactor by solving the Navier–Stokes equations. For turbulent flow, a low Reynolds number k— model is used to calculate the turbulent viscosity. Using the obtained flow field and turbulent viscosity, the current density distribution is calculated for different flow velocities by solving the equations describing the transport of multiple ions due to diffusion, convection and migration. For the laminar case, a very good agreement with literature data is obtained. For turbulent flow, different numerical models for turbulent mass transfer are proposed in the literature. A detailed study of the behaviour close to the wall of these different turbulence models is presented, together with a comparison of the calculated results with literature correlations. This allows identification of the benefits and disadvantages of each of the turbulence models for the numerical calculation of mass transfer at high Schmidt numbers in a parallel plate reactor.     

A comprehensive survey of industry practice in real-time systems

Real-Time Systems - This paper presents results and observations from a survey of 120 industry practitioners in the field of real-time embedded systems. The survey provides insights into the...     

What is moral about guilt? Acting “prosocially” at the disadvantage of others.

For centuries economists and psychologists have argued that the morality of moral emotions lies in the fact that they stimulate prosocial behavior and benefit others in a person's social environment. Many studies have shown that guilt, arguably the most exemplary moral emotion, indeed motivates prosocial behavior in dyadic social dilemma situations. When multiple persons are involved, however, the moral and prosocial nature of this emotion can be questioned. The present article shows how guilt can have beneficial effects for the victim of one's actions but also disadvantageous effects for other people in the social environment. A series of experiments, with various emotion inductions and dependent measures, all reveal that guilt motivates prosocial behavior toward the victim at the expense of others around—but not at the expense of oneself. These findings illustrate that a thorough understanding of the functioning of emotions is necessary to understand their moral nature. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Guaranteed frame rate: a better service for TCP/IP in ATM networks

Guaranteed frame rate, approved by the ATM Forum, is expected to become an important service category to efficiently support TCP/IP traffic in ATM networks. We first describe the GFR traffic contract in detail. We then present different types of switch implementations that have been proposed to support GFR. We analyze the performance of three of these switch implementations by simulations in two different network environments. These simulations show that the scheduler-based implementations provide a much better performance than the simple switch implementation. However, we also show that coupling an active packet discard mechanism to a scheduler-based switch implementation does not produce a performance gain when many TCP connections are multiplexed inside one ATM VC     

STM measurements on graphite using correlation averaging of the data

Images of the (0001) surface of highly oriented pyrolytic graphite observed using scanning tunnelling microscopy, in both constant distance and current imaging modes, show a strong asymmetry of the unit cell. This asymmetry depends on the tunnelling current and voltage. We have also found clear evidence that multiple-tip tunnelling occurs. To improve the resolution of the imaged unit cells, a method of correlation averaging is introduced.     

Phylogenetic classification of the major superfamily of membrane transport facilitators, as deduced from yeast genome sequencing

From the approximately 5000 open reading frames presently identified by systematic sequencing of the yeast genome, 100 Saccharomyces cerevisiae transport proteins belonging to the major facilitator superfamily (MFS), were assigned to 17 families on the basis of extensive database searches and binary comparisons. These families include multidrug resistance proteins and transport proteins for sugars, amino acids, uracil/allantoin, allantoate, phosphate, purine/cytosine, proteins, peptides, potassium, sulfate, and urea. Four new families of unknown function have been identified. For the sugar and amino acid transport proteins, alignments were made and phylogenetic trees were constructed allowing the identification of several clusters of proteins presumably exhibiting similar transport functions.