Emission control of SO2 and NOx by irradiation methods

Microwave discharges at 2.45 GHz frequency and accelerated electron beams operated at atmospheric pressure in synthetic gas mixtures containing N(2), O(2), CO(2), SO(2), and NO(x) are investigated experimentally for various gas mixture constituents and operating conditions, with respect to their ability to purify exhaust gases. An original experimental unit easily adaptable for both separate and simultaneous irradiation with microwaves and electron beams was set up. The simultaneous treatment with accelerated electron beams and microwaves was found to increase the removal efficiency of NO(x) and SO(2) and also helped to reduce the total required dose rate with approximately 30%. Concomitant removal of NO(x) ( approximately 80%) and SO(2) (>95%) by precipitation with ammonia was achieved.     

Studies of 2.45 GHz microwave induced plasma abatement of CF4

Microwave plasmas at 2.45 GHz frequency operated at atmospheric pressure in synthetic gas mixtures containing N2 and CF4 are investigated experimentally for various operating conditions, with respect to their ability to destroy perfluorocompounds. It was found that the destruction and removal efficiency of the process is highly dependent on the total gas flow and concentration of CF4. Destruction and removal efficiencies of CF4 up to 98% have been achieved using 1.9 kW of microwave power at 16 L/min total flow rate.     

Electrodeposition of Cu from acidic sulphate solutions containing cetyltrimethylammonium bromide (CTAB)

In this paper we report a study of the electrodeposition of Cu from an acidic sulphate solution containing cetyltrimethylammonium bromide (CTAB). This investigation is based on cyclic voltammetry, in situ surface-enhanced Raman spectroscopy (SERS), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Adsorption of CTAB over a wide range of cathodic potentials was proved spectroelectrochemically, encompassing both conditions where compact and loose Cu grows (up to −0.4 and between −0.4 and −1 V vs. Ag/AgCl, respectively). Furthermore, we found that CTAB tends to react cathodically, undergoing the loss of the aliphatic tail at lower cathodic potentials and the formation of an allylic product at higher polarisations. CTAB deeply impacts the Cu growth mode: ordered ridges of compact Cu crystallites form at low cathodic potentials—where the electrodeposition process is strongly inhibited by CTAB adsorption—and nanoparticles grow under hydrogen-evolution conditions.     

Numerical Simulation of Re-Entry Flow: Heat Flux Evaluation

Abstract

The problem of heat transfer in a four channel plate heat exchanger involving the effect of unsymmetrical heat transfer in the outer two channels is studied analytically and experimentally. An energy balance over a control volume yields the governing system of differential equations that has been solved exactly for the cases of parallel flow and counterflow to give the temperature distribution in the channels. The results show that zero or even reversed heat flow may be obtained at the middle plate of the heat exchanger. Expressions for the heat exchanger efficiency and the log-mean temperature difference correction factor in terms of the heat capacity rate ratio and the number of transfer units are presented. Experiments carried out with a counterflow plate heat exchanger show reasonable agreement between the experimentally observed and the theoretically calculated efficiencies and mean driving temperature differences.     

The hepatopancreas enzymes of the crustaceans Munida and their potential application in cheese biotechnology

Proteolytic and peptidase activities were extracted from the hepatopancreas of the crustaceans Munida and characterized by enzymatic assay, 2D zymography and mass spectrometry. Results showed the presence of several isotrypsin-like and isochymotrypsin-like enzymes, aminopeptidases and carboxypeptidases A and B. Six different acidic forms of trypsin were detected using specific inhibitors and 2D zymography. Trypsin-like activity was higher than chymotrypsin-like activity. On the basis of previous evidences in food biotechnology and cheese production, the digestive enzymes of the crustaceans Munida were tested for their ability to degrade casein, a process involved in cheese production. As a result, the Munida enzymes were found to degrade the chymosin-derived β-casein fragment f193-209, one of the peptides associated with bitterness in cheese, revealing their possible application in cheese technology to lower the unpleasant bitter flavour in some cheeses.     

Economy analysis of the implementation of extruded tiles fabrication in a ceramic industry containing ornamental rock waste

As a result of the economic crisis faced in Brazil, industries in the red ceramic sector have economic problems. The objective of this work was to evaluate, technologically and economically, through analysis of economy, the implementation of the production of ceramic tiles, a material with higher added value than bricks and ceramic blocks, in a ceramic industry located in the state of Rio de Janeiro, Brazil. The ceramic tiles were produced containing the incorporation of ornamental rock waste (ORW). The state has a region that has a red ceramic pole, but produces only products with lower added value. For this, specimens were produced with four different ceramic masses burned at temperatures in the range of 800 to 1050°C. Three masses were produced with different clays from the region (ceramic mass 1, 2 and 3) and a ceramic mass 4 was evaluated containing the clay that presented the best results and with the inclusion of sand and ORW, aiming at the analysis of economy. It was found that the masses containing only clays showed satisfactory parameters of resistance, but showed deficiencies in water absorption. The fourth mass, however, presented acceptable values in all the evaluated properties and was chosen to carry out a full-scale industrial test, which enabled the development of economic analysis and an economic analysis using the theory of real options. The results obtained in this last stage were also positive, providing an internal rate of return of 16.82%, above the minimum practiced rate of 15%, proving the efficiency of the economy applied to the manufacture of extruded tiles in the industries of the study region.     

Outer Membrane Vesicles Derived from Klebsiella pneumoniae Are a Driving Force for Horizontal Gene Transfer

Gram-negative bacteria release Outer Membrane Vesicles (OMVs) into the extracellular environment. Recent studies recognized these vesicles as vectors to horizontal gene transfer; however, the parameters that mediate OMVs transfer within bacterial communities remain unclear. The present study highlights for the first time the transfer of plasmids containing resistance genes via OMVs derived from Klebsiella pneumoniae (K. pneumoniae). This mechanism confers DNA protection, it is plasmid copy number dependent with a ratio of 3.6 times among high copy number plasmid (pGR) versus low copy number plasmid (PRM), and the transformation efficiency was 3.6 times greater. Therefore, the DNA amount in the vesicular lumen and the efficacy of horizontal gene transfer was strictly dependent on the identity of the plasmid. Moreover, the role of K. pneumoniae-OMVs in interspecies transfer was described. The transfer ability was not related to the phylogenetic characteristics between the donor and the recipient species. K. pneumoniae-OMVs transferred plasmid to Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa and Burkholderia cepacia. These findings address the pivotal role of K. pneumoniae-OMVs as vectors for antimicrobial resistance genes spread, contributing to the development of antibiotic resistance in the microbial communities.     

Selection and Use of Phytate-Degrading LAB to Improve Cereal-Based Products by Mineral Solubilization During Dough Fermentation

ABSTRACT:  New producers of phytate-degrading enzymes, especially lactic acid bacteria (LAB), were used to improve mineral solubilization during dough fermentation. In all, among strains from different sources by microorganisms (150 lactic acid bacteria, 36 yeasts), 38 (24%) exhibited a clear zone around the colonies by hydrolyzing hexacalcium phytate contained in solid medium. When phytase-positive strains from plate assay were tested for phytase activity in liquid medium, 6 of the strains (37%) exhibited phytate-degrading activity in at least one of the 3 different media used. Of the LAB, the highest phytase values were found for  Enterococcus faecium  A86 (0.74 U/mL) and  Lactobacillus plantarum  H5 (0.71 U/mL). Two different starter cultures obtained by combinations of phytase-positive (phy+:  L. plantarum  H5 and L3,  Leuconostoc gelidum  A16, and  E. faecium  A86) or phytase-negative (phy−:  L. gelidum  LM249,  L. plantarum  H19, and  L. plantarum  L8) selected LAB strains, were used to measure mineral concentrations of iron, zinc, and manganese during dough fermentation. Although the 2 kinds of starter showed similar acidic values, the presence of phytate-degrading LAB strains increased mineral solubilization in comparison to the starter phy−.