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Copyright of Revista Medica del IMSS is the property of Direccion de Prestaciones Medicas - IMSS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The paper describes the protection circuit designed as a technological improvement in OZONEY SL, Ozone Generator Equipment designed by engineers at National Center for Scientific Research. This ozone generator is utilized on treatment of water from 450l/h. Ambient air is used to produce ozone gas by means of high voltage. The new design was necessary because of the difficulties produced by absence of water supply for treatment. Some failures affect the equipment if it does not have water to treat. In this case some equipment installed in different organizations has been damaged, because the equipment has been designed to work automatically according to the consumption. To solve this problem a new block of Control and Protection was incorporated to protect the equipment. This paper describes the new control and protection circuit, the block diagrams and how to connect to the original equipment. [ABSTRACT FROM AUTHOR]

Copyright of Revista EIA is the property of Escuela de Ingenieria de Antioquia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Dilemas Contemporáneos: Educación, Política y Valores is the property of Dilemas Contemporaneos: Educacion, Politica y Valores and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The ozone generation systems generally use the pulse amplitude modulation (PAM) to vary or control the ozone concentration. The results obtained after the implementation of pulse density modulation (PDM) in the power supply system of an ozone generation and the improvement achieved in the efficiency curve is presented in this paper. PAM and PDM techniques were applied in ozone generation system with push-pull inverter resonant self. The adjusted voltage amplitude of the PDM waveform power is determined from the condition of the PAM waveform where the maximum efficiency was obtained; Thus achieving increased efficiency in 60% of operating points ozone generation system. [ABSTRACT FROM AUTHOR]

In this paper, the results obtained by analyzing time series of ground level energy of the solar radiation in the 305 nm band and stratospheric ozone layer thickness are shown. The most relevant feature found is the independence of the variability of the ground level energy with respect to the short period variations of the ozone layer, being the meteorological local effects those which more heavily affect the variability. [ABSTRACT FROM AUTHOR]

Ozone efficiency in the water treatment systems is widely published in national and international papers. The criteria design of the treatment plants have changed over the years with increasing knowledge about the mechanism through which ozone reacts with chemical and microbiological pollutants. It recognizes the existence of a relationship between morphological and physiological characteristics of microorganisms and their resistance to ozone. However, there are few studies reported about the mechanisms by which ozone inactivates microorganisms in aqueous media. The aim of this study was to evaluate the effect of ozone on cytoplasmic membrane and enzymes related to oxidative balance on two microorganisms: Escherichia coli ATCC 25922 and Salmonella enterica var. Thyphimurium ATCC 12 048. From a kinetic study was determined, the variation of the efflux of potassium, changes in SH groups and the action exerted by ozone on the enzymes catalase and superoxide dismutase. The results showed an involvement of SH groups present, mainly, in protein and the potassium efflux outside microbial cells, demonstrating that these compound are among the first targets of ozone on microorganisms. An increased activity of the catalase enzyme and a decreased activity of superoxide dismutase enzyme were observed. The decrease in the relationship between these two enzymes suggests that the antioxidant systems of microorganisms are not able to counteract the damage caused by ozone. [ABSTRACT FROM AUTHOR]

Ozone efficiency in the water treatment systems is widely published in national and international papers. The criteria design of the treatment plants have changed over the years with increasing knowledge about the mechanism through which ozone reacts with chemical and microbiological pollutants. It recognizes the existence of a relationship between morphological and physiological characteristics of microorganisms and their resistance to ozone. However, there are few studies reported about the mechanisms by which ozone inactivates microorganisms in aqueous media. The aim of this study was to evaluate the effect of ozone on cytoplasmic membrane and enzymes related to oxidative balance on two microorganisms: Escherichia coli ATCC 25922 and Salmonella enterica var. Thyphimurium ATCC 12 048. From a kinetic study was determined, the variation of the efflux of potassium, changes in SH groups and the action exerted by ozone on the enzymes catalase and superoxide dismutase. The results showed an involvement of SH groups present, mainly, in protein and the potassium efflux outside microbial cells, demonstrating that these compound are among the first targets of ozone on microorganisms. An increased activity of the catalase enzyme and a decreased activity of superoxide dismutase enzyme were observed. The decrease in the relationship between these two enzymes suggests that the antioxidant systems of microorganisms are not able to counteract the damage caused by ozone. [ABSTRACT FROM AUTHOR]

This paper compares experimental results on methylene blue (MB) removal systems based on ozone oxidation, zeolite adsorption, and simultaneous adsorption-oxidation using ozone in the presence of natural zeolite. The effect of pH (2-8), and the presence of radical scavengers (sodium acetate) on process rates and removal efficiencies are assessed at laboratory scale. The experimental system consisted of a IL differential circular flow reactor and an ozone generator rated at 5 g O3/h. Results show that ozone oxidation combined with zeolite adsorption increases the overall MB oxidation rate with respect to ozonation process and zeolite adsorption. In presence of free radical scavenger only a 25% of reduction on MB removal rate are observed in the simultaneous treatment, as compared with 70% when ozonation treatment is used, suggesting that MB oxidation reactions take mainly place on the zeolite surface. [ABSTRACT FROM AUTHOR]

The objectives of the paper consisted of the evaluation of the economic impact and the water microbiological quality, by applying ozone disinfection. This technology has been installed in water bottled industry, as well as in facilities for the breeding of pathogenic germ-free animals located in the National Center of Laboratory Animal Production and in the Genetic and Biotechnology Engineering Center facilities, where the laboratory animals remain during different drugs evaluation. A procedure to estimate the applied ozone dose and the dissolved ozone concentration at the contact column exit was used. The use of a single contact stage in the practice was valid. The ozone applied in the water treatment as in the bottling of water, as in production units of laboratory animals has a high economic and technical feasibility as compared to other treatments. Ozone guarantees efficient water disinfection. An appropriate treatment for the elimination of microbiological contamination for Pseudomonas aeruginosa in water bottled industry was not found. However, the water ozonization during the bottling process and sanitizing the plant lines, with a high dissolved ozone concentration, provides an adequate disinfection. The conventional thermal water treatment used for the consumption of laboratory animals is difficult and very expensive, being the annual production cost of the ozone treatment around seven times cheaper. [ABSTRACT FROM AUTHOR]

This paper presents the ozonization evaluation of a secondary effluent. Parameters of reactor design as the value of the initial demand and the kinetic constant of consumption of ozone were determined. The obtained values were 1,6 mg/L and 0,192 min-1 respectively. As well as, ozone effluent disinfection was evaluated to determine the most appropriate operation conditions, to guarantee a sure disinfection and to diminish the environmental impact. The ozonization effect on the quality effluent parameters was evaluated. They were chemistry oxygen demand, the absorbance value to 254 nm, conductivity, pH, biochemical oxygen demand and total suspended solids total. The ozone disinfection was very effective for the inactivation of total and fecal coliforms with a Ct of 5 mg.min/L. On the other hand, the secondary effluent was inoculated with a concentration of 3,4 x 10² UFC/mL of Pseudomonas aeruginosa, to simulate a potential contamination. This pathogen microorganism is frequent in this wastewater and it is resistant to the chloration. The results indicated that a dose of 7 mg/L during 5 minutes is enough. The ozone reduces the environmental impact as disinfection stage, since the high chlorine doses generate residual concentrations higher than 3 mg/L. Which is not desirable and it constitutes an ecological risk for the population health, that is supplied of the water receiver body. A design of the contact system was proposed. The chlorination tank can be used as ozonization reactor with a minimum of modifications. The investment costs can be reduced. This diminishes the investment cost for construction cost reduction. A bubble reactor with double baffles is proposed. It is composed by two mixing chambers. The countercurrent contact among the phases is guaranteed. In the third chamber ozone is not injected. The double baffles are recommended to avoid the short circuit effect. [ABSTRACT FROM AUTHOR]

Prior studies have proven that proton Nuclear Magnetic Resonance technique can be used to follow up ozone reaction with unsaturated fatty acids. In this paper, ozonation of sunflower oil at a different applied ozone dosage was carried out and peroxide index and aldehydes contents were determined. The reaction products were identified using Proton Nuclear Magnetic Resonance Spectroscopy (¹H NMR). The principal signal intensities values were used for following the reaction course between ozone and sunflower oil. The reaction was following up to peroxide index values of 1 202 mmol-equiv/kg . The intensities of olefinic proton signals decreased with the gradual increase in ozone concentration but without disappearing completely. The Criegee ozonides obtained at 107.1 mg/g of ozone doses were approximately 7.4 folds higher than that at the beginning of reaction. The aldehyde protons were observed as a weak intensity signal in all the spectra. The signals belonging to olefinic protons from hydroperoxides appeared weak with the increase in ozone doses. Signals from other oxygenized groups were assigned. It was concluded that the higher applied ozone doses the higher the ozonation reaction advance corresponding with a higher oxygenized compounds formation. [ABSTRACT FROM AUTHOR]

Copyright of Revista Mutis is the property of Revista Mutis and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)