Institute Ingenieria Quimica

Dieciocho de Julio, Uruguay

Institute Ingenieria Quimica

Dieciocho de Julio, Uruguay

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Troconis De Rincon O.M.,University of Zulia | Sanchez M.,University of Zulia | Millano V.,University of Zulia | Fernandez R.,University of Zulia | And 25 more authors.
Concrete under Severe Conditions: Environment and Loading - Proceedings of the 6th International Conference on Concrete under Severe Conditions, CONSEC'10 | Year: 2010

This investigation presents some of the results from an Iberoamerican project called DURACON in a five-year period (nine countries, 16 sites). This project correlates the influence of urban and marine meteorochemical parameters on the performance of reinforced concrete structures. The environment was evaluated using ISO Standard 9223 and the concrete was characterized physically by measuring compressive strength, elastic modulus, total and effective porosity, as well as resistance to water absorption. After a one-year exposure period, the results of the corrosion potentiality and probability analysis of the reinforcement in the different test stations show that the concrete prepared in Venezuela is the one that has the greatest probability of carbonation-induced corrosion of the reinforcement, with the test site at Cali, Colombia being the one that would induce least corrosion. These results are comparable with those found using electrochemical measurements, after a five-year exposure period. © 2010 Taylor & Francis Group, London.


Loperena L.,Institute Ingenieria Quimica | Soria V.,Institute Ingenieria Quimica | Varela H.,Institute Ingenieria Quimica | Lupo S.,Institute Biologia | And 7 more authors.
World Journal of Microbiology and Biotechnology | Year: 2012

Antarctic environments can sustain a great diversity of well-adapted microorganisms known as psychrophiles or psychrotrophs. The potential of these microorganisms as a resource of enzymes able to maintain their activity and stability at low temperature for technological applications has stimulated interest in exploration and isolation of microbes from this extreme environment. Enzymes produced by these organisms have a considerable potential for technological applications because they are known to have higher enzymatic activities at lower temperatures than their mesophilic and thermophilic counterparts. A total of 518 Antarctic microorganisms, were isolated during Antarctic expeditions organized by the Instituto Antártico Uruguayo. Samples of particules suspended in air, ice, sea and freshwater, soil, sediment, bird and marine animal faeces, dead animals, algae, plants, rocks and microbial mats were collected from different sites in maritime Antarctica. We report enzymatic activities present in 161 microorganisms (120 bacteria, 31 yeasts and 10 filamentous fungi) isolated from these locations. Enzymatic performance was evaluated at 4 and 20°C. Most of yeasts and bacteria grew better at 20°C than at 4°C, however the opposite was observed with the fungi. Amylase, lipase and protease activities were frequently found in bacterial strains. Yeasts and fungal isolates typically exhibited lipase, celullase and gelatinase activities. Bacterial isolates with highest enzymatic activities were identified by 16S rDNA sequence analysis as Pseudomonas spp., Psychrobacter sp., Arthrobacter spp., Bacillus sp. and Carnobacterium sp. Yeasts and fungal strains, with multiple enzymatic activities, belonged to Cryptococcus victoriae, Trichosporon pullulans and Geomyces pannorum. © 2012 Springer Science+Business Media B.V.


Troconis De Rincon O.M.,University of Zulia | Sanchez M.,University of Zulia | Millano V.,University of Zulia | Fernandez R.,University of Zulia | And 25 more authors.
18th International Corrosion Congress 2011 | Year: 2011

This investigation presents some of the results from an Iberoamerican project called "Effect of the environment on reinforcement durability" (DURACON) in its six years period. This project correlates the influence of urban and marine meteorochemical parameters on the performance of reinforced concrete structures. The present paper presents the results from 16 test sites distributed among nine countries (Bolivia, Chile, Colombia, Costa Rica, Mexico, Spain, Uruguay, Portugal and Venezuela). The environment was evaluated using ISO Standard 9223 and the concrete was characterized physically by measuring compressive strength, elastic modulus, total and effective porosity, as well as the effective porosity and resistance to water absorption using the Fagerlund method. To that effect, concrete specimens (with and without reinforcement) were prepared for electrochemical and physical/mechanical/chemical tests using the existing materials in each participating country, following strict procedures which enabled the preparation of similar concrete specimens. Two water/cement (w/c) ratios (0.45 and 0.65) were selected, where 0.45 w/c ratio concrete had a minimum cement content of 400 kg/m 3 and the one with 0.65 w/c ratio a minimum 28-day compressive strength of 210 kg/cm 2. Type I Portland cement, siliceous sand, and crushed rock as coarse aggregates (13-mm maximum nominal size) were used. After a one-year exposure period, the results of the corrosion potentiality and probability analysis of the reinforcement in the different test stations show that the concrete prepared in Venezuela is the one that has the greatest probability of carbonation-induced corrosion of the reinforcement, with the test site at Cali, Colombia being the one that would induce least corrosion. These results are comparable with those found using electrochemical measurements, after a six-year exposure period. The results also showed high carbonation aggressiveness of the tropical environments, being Venezuela one of the countries in Iberoamerica, with the most aggressive ones.


Bianchi A.C.,Institute Ingenieria Quimica | Olazabal L.,Laboratorio Tecnologico del Uruguay | Torre A.,Laboratorio Tecnologico del Uruguay | Loperena L.,Institute Ingenieria Quimica
World Journal of Microbiology and Biotechnology | Year: 2014

Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are long-chain polyunsaturated fatty acids (PUFAs) that belong to the omega-3 group. They are essential fatty acids found in phospholipid of cell membranes. There is strong evidence that these nutrients may also favorably modulate many diseases. Primary sources of omega-3 PUFAs in the human diet are fish and fish-derived products. The fishing industry worldwide, however, is becoming unable to satisfy the growing demand for these PUFAs. A promising cost-effective alternative source of PUFAs is bacterial production. We identified 40 Antarctic marine bacterial isolates by 16S rRNA gene sequence analysis. Fifteen genera in three phyla were represented in the collection. Isolates were tested for ability to produce EPA using a method in which their ability to reduce 2,3,5-triphenyltetrazolium chloride (TTC) is determined and by gas chromatography coupled to mass spectrometry (GC-MS). All isolates could reduce TTC, and GC-MS analysis showed that four produced EPA and that six produced DHA. We show for the first time that isolates identified as Cellulophaga, Pibocella and Polaribacter can produce EPA and DHA, only DHA or only EPA, respectively. One isolate, Shewanella sp. (strain 8-5), is indicated to be a good candidate for further study to optimize growth and EPA production. In conclusion, a rapid method was tested for identification of new EPA producing strains from marine environments. New EPA and DHA producing strains were found as well as a potentially useful PUFA production strain. © 2014 Springer Science+Business Media Dordrecht.


Ohanian M.,Institute Ingenieria Quimica | Martinez-Luaces V.,Institute Ingenieria Quimica
International Journal of Corrosion | Year: 2014

The potential distribution in tubes of a heat exchanger is simulated when applying cathodic polarization to its extremes. The comparison of two methods to achieve this goal is presented: a numeric solution based on boundary elements carried out with the commercial software Beasy-GID and a semianalytical method developed by the authors. The mathematical model, the simplifications considered, and the problem solving are shown. Since both approaches use polarization curves as a boundary condition, experimental polarization curves (voltage versus current density) were determined in the laboratory under flow conditions and cylindrical cell geometry. The results obtained suggest the impossibility of extending the protection along the whole tube length; therefore, other protection methods are considered. © 2014 Mauricio Ohanian and Víctor Martínez-Luaces.


PubMed | Institute Ingenieria Quimica
Type: Journal Article | Journal: World journal of microbiology & biotechnology | Year: 2012

Antarctic environments can sustain a great diversity of well-adapted microorganisms known as psychrophiles or psychrotrophs. The potential of these microorganisms as a resource of enzymes able to maintain their activity and stability at low temperature for technological applications has stimulated interest in exploration and isolation of microbes from this extreme environment. Enzymes produced by these organisms have a considerable potential for technological applications because they are known to have higher enzymatic activities at lower temperatures than their mesophilic and thermophilic counterparts. A total of 518 Antarctic microorganisms, were isolated during Antarctic expeditions organized by the Instituto Antrtico Uruguayo. Samples of particules suspended in air, ice, sea and freshwater, soil, sediment, bird and marine animal faeces, dead animals, algae, plants, rocks and microbial mats were collected from different sites in maritime Antarctica. We report enzymatic activities present in 161 microorganisms (120 bacteria, 31 yeasts and 10 filamentous fungi) isolated from these locations. Enzymatic performance was evaluated at 4 and 20C. Most of yeasts and bacteria grew better at 20C than at 4C, however the opposite was observed with the fungi. Amylase, lipase and protease activities were frequently found in bacterial strains. Yeasts and fungal isolates typically exhibited lipase, celullase and gelatinase activities. Bacterial isolates with highest enzymatic activities were identified by 16S rDNA sequence analysis as Pseudomonas spp., Psychrobacter sp., Arthrobacter spp., Bacillus sp. and Carnobacterium sp. Yeasts and fungal strains, with multiple enzymatic activities, belonged to Cryptococcus victoriae, Trichosporon pullulans and Geomyces pannorum.

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