Effect of the injection-nozzle geometry on the interaction between a gas–liquid jet and a gas–solid fluidized bed

In industrial fluid cokers, bitumen is first mixed with steam in a premixer, and then fed to the atomization nozzle. The objective of this work was to evaluate the impact of both the premixer and the nozzle geometrical configuration on the quality of the liquid–solid contact resulting from injections of liquid into a gas–solid fluidized bed. To assess the quality of the liquid–solid contact a method based on electric conductance measurements of the bed material previously developed by the authors [9] was used. Liquid atomization efficiency in open air, spray geometry, and spray stability were also characterized to evaluate their effects on the nozzle spraying performance within the fluidized bed. This study indicated that spray stability is highly beneficial to the liquid–solid contact efficiency. In particular, fluid constrictions such as the series of converging and diverging sections within the nozzle have a stabilizing effect on the spray. Future optimization of the existing liquid-injection systems should consider alternative gas–liquid premixers and nozzle geometries to enhance the jet stability.     

Ranking of TOA Measurements Based on the Estimate of the NLOS Propagation Contribution in a Wireless Location System

The presence of non-line-of-sight (NLOS) propagation is a key issue that limits the accuracy of wireless location systems. The lack of direct sight causes the measurements obtained by location systems to be so unpredictable that they can produce high inaccuracies in the estimation of the mobile station location. In this paper we propose a novel technique to improve location reliability and accuracy in cases where NLOS propagation is present. For that, in registers of time of arrival (TOA) measurements taken from each base station (BS) in view, we detect the presence of NLOS propagation and estimate the ratio of the measurements coming from NLOS propagation. With this estimate we can assess how much is NLOS propagation affecting the measurements taken from each BS and then we can identify the best measurements and BSs to achieve the highest accuracies in location.     

Environmental Performance of Pseudomonas putida with a Uracylated Genome

A variant of the soil bacterium Pseudomonas putida with a genome containing a ∼20 % replacement of the whole of thymine (T) by uracil (U) was made by deleting genes ung (uracil DNA glycosylase) and dut (deoxyuridine 5′-triphosphate nucleotide hydrolase). Proteomic comparisons revealed that, of 281 up-regulated and 96 down-regulated proteins in the Δung Δdut cells, as compared to the wild-type, many were involved in nucleotide metabolism. Unexpectedly, genome uracylation did not greatly change the gross environmental endurance profile of P. putida, increased spontaneous mutagenesis by only twofold and supported expression of heterologous proteins well. As U-enriched DNA is potentially degraded by the base excision repair of recipients encoding a uracil DNA glycosylase, we then tested the spread potential of genetic material originating in the Δung Δdut cells either within the same species or in a commonly used Escherichia coli strain. Transformation and conjugation experiments revealed that horizontal gene transfer of U-containing plasmids fared worse than those made of standard DNA by two orders of magnitude. Although this figure does not guarantee the certainty of containment, it suggests a general strategy for curbing the dispersal of recombinant genetic constructs.     

Transient analysis of non-Markovian models using stochastic state classes

The method of stochastic state classes approaches the analysis of Generalised Semi Markov Processes (GSMPs) through the symbolic derivation of probability density functions over supports described by Difference Bounds Matrix (DBM) zones. This makes steady state analysis viable, provided that at least one regeneration point is visited by every cyclic behaviour of the model.We extend the approach providing a way to derive transient probabilities. To this end, stochastic state classes are extended with a supplementary timer that enables the symbolic derivation of the distribution of time at which a class can be entered. The approach is amenable to efficient implementation when model timings are given by expolynomial distributions, and it can be applied to perform transient analysis of GSMPs within any given time bound. In the special case of models underlying a Markov Regenerative Process (MRGP), the method can also be applied to the symbolic derivation of local and global kernels, which in turn provide transient probabilities through numerical integration of generalised renewal equations. Since much of the complexity of this analysis is due to the local kernel, we propose a selective derivation of its entries depending on the specific transient measure targeted by the analysis.     

Does bottle color protect red wine from photo‐oxidation?

Even if bottled red wines have an extended shelf life, they undergo several chemical changes, and producers are well aware of the importance of the packaging. However, there is a lack of research into the effect of light on their composition. Therefore, the storage conditions of a Sangiovese wines with respect to artificial light exposure (present/absent) and bottle color (transparent, brown, and green) were investigated. Thirty‐five chemical characteristics (physicochemical, UV‐VIS indexes, and volatile compounds) were recorded after 6 months of storage. Light exposure caused significant differences in total SO₂ and a shift from red to yellow/orange color. For wines kept in transparent bottles, total red pigments, total phenol index, monomeric anthocyanins, copigmentation, chemical age, and some volatile compounds showed significant differences, depending on whether it was exposed to light or not. On the contrary, light exposure was found not significant for the wine stored in green and brown bottles, Finally, an overall increase in variability was found for light‐exposed wine in transparent bottles which could be considered, in itself, a measure of lack of quality.