NATIONAL CENTER FOR SCIENTIFIC RESEARCH (CENIC) CHEMICAL SCIENCES JOURNAL

ANALYSIS OF ATMOSPHERIC CORROSION AFFECTIONS ON REINFORCED CONCRETE STRUCTURES IN CRUCITA, PORTOVIEJO, MANABÍ, ECUADOR

2025-02-28T11:55:16-05:00

A study on atmospheric corrosion affectations analysis in 10 reinforced concrete structures located at different distances from the coastline in Crucita, Manabí, Ecuador was carried out. To define the type of service life of the structures was the main objective. Compressive Strength (Rc-MPa) obtained from Sclerometry, Apparent Electrical Resistivity (ρ-kΩ/cm) and Corrosion Current Intensity (Ic-µA/cm²) were measured in a column in each of the structures. The results showed that the 10 reinforced concrete structures were found in its residual service life without functioning, confirmed by visual observation. From the behavior of Rc, ρ and Ic values it was possible to confirm that the concrete used did not present the necessary and sufficient quality for the structures to have maintained over time its initial service life conditions of the project, such as aesthetics, functionality and safety in the coastal zone with high construction potential. According to the fit of statistical models based on multiple linear regressions, it was further demonstrated that Rc and Total Chloride Ion Concentration (), including its penetration mechanism from the surface to the concrete interior, were necessary and very influential factors in the adequate durability performance of concrete. It was demonstrated, as a first experience in Ecuador and not much taken into account worldwide, to calculate whenever possible, the coefficient, as another indicator in the evaluation of the quality of concrete, which represents, in addition to the speed with which the could penetrate in the concrete, the relationship between the concrete quality with the natural environment of

EVALUATION OF THE FORMATION OF BIOPRODUCTS OF INTEREST TO MEOR

2025-05-29T15:22:58-04:00

Among the most prevalent problems affecting the oil industry is the low efficiency of hydrocarbon extraction from natural reservoirs. Given this situation, the use of biotechnology as a tool for enhanced oil recovery has become an attractive and economically feasible alternative. In this regard, there has been renewed interest worldwide in methodologies that include the use of microorganisms. MEOR (Microbial Enhanced Oil Recovery) is a general term that refers to the use of microorganisms such as bacteria and/or archae and their metabolic products (acids, gases, biopolymers, biosurfactants and others). MEOR microbiological processes are considered advantageous over physical-chemical variants because they are cheaper, consume less energy, do not depend on oil prices and do not use substances that are aggressive to the environment because they are biodegradable. The objective of the research was to evaluate the potential of native microorganisms from drilling wells for use in MEOR processes. Microorganisms were isolated from the Cuban Northern Oil Belt sector, where characteristics of interest were assessed, such as acid and gas production, qualitative determination of biofilm formation (presence of exopolysaccharides) through adherence to Congo red, as well as the production of bio-surfactants through three different methods: drop collapse, interfacial tension and oil dispersion. From the tests carried out on the strains, Strain No. 241-2 was found to be the most satisfactory for continuing with the MEOR process tests. Strains No. 237-1 and 237-2 were discarded for future research, as they did not meet any of the requirements in the tests carried out.

OZONE BLEACHING OF CELLULOSIC FIBRES. EXPERIENCE WITH TOWELS

2025-05-29T15:46:16-04:00

The bleaching method with hydrogen peroxide is expensive due to the high consumption of products, water and energy, while with ozone it is very advantageous. The objective of this study was to evaluate the use of ozone in the bleaching of towel samples, made of terry fiber fabric, 100 % cotton. Raw and pretreated samples (desizing-scouring) were used, at pH 5, with water content of 30 %. The experiments were carried out at room temperature, with exposure times: 5 to 30 min; gas flows: 10 and 20 L h-1; concentrations of ozone in the gas: 40 to 80 mg L-1. The degree of whiteness (GB) and degree of polymerization (GP) were measured, comparing them with bleaching with hydrogen peroxide for dyeing. The pretreatment of the fabric indicated a favorable effect, but the increase in gas flow did not. Ozone bleaching was improved by increasing the time and the concentration of ozone in the gas. However, short times are recommended to avoid damage to the fabric. The efficiency of the process improved by increasing the humidity of the reactor inlet gas. Under the experimental conditions evaluated, no effect on hydrophilicity was observed. The GB of the pretreated and ozonated samples up to 10 min, applying dry gas, was similar to the conventional process for dyeing pastel tones, but with some degradation. While, applying the wet gas, the ozonized raw fabric (10 min) reached a GB to dye medium to dark tones without affecting the required GP. Bleaching of raw fabrics was.

APLICACIÓN DE LA CIENCIA SENSORIAL MOLECULAR EN LA DETERMINACIÓN DEL SABOR DE LOS ALIMENTOS: UNA REVISIÓN

2025-05-30T11:54:28-04:00

Molecular sensory science (MSS) or sensomics represents a multidisciplinary and integrated methodology focused on exploring the sensory attributes of food at the molecular level. By focusing on the molecular interactions responsible for flavor and aroma, MSS has revolutionized the way flavors are determined and characterized. The object of the present work was to examine the methodologies, applications, and emerging trends in molecular sensory analysis, emphasizing its role in the food industry. The most commonly used methods for the development of MSS are discussed, as well as a thematic search in the Scopus database on MSC up to 2024. Within the MSS approach, gas chromatography coupled with mass spectrometry and olfactometry has been used to determine the key odor-active compounds. Dilution analysis, detection frequency, and time-intensity methods are used to identify these aroma-active compounds. Additionally, Odor Activity Values (OAVs) are calculated to determine the individual contribution of each volatile compound to the characteristic aroma of the food. Furthermore, aroma reconstitution tests and omission tests are conducted to confirm the importance of these key compounds in shaping the overall flavor profile of the food. Key advances were shown, such as gas chromatography-olfactometry (GC-O), gas chromatography-olfactometry-mass spectrometry (GC-MS-O), aroma extract dilution analysis (AEDA), and the role of omics technologies, which have impacted MSS in optimizing flavor, food quality, and consumer acceptance.