Relación entre el A/CA medido con el método del gradiente y el de las heteroforias en Pereira

El presente estudio busca determinar los valores promedio y la correlación de la razón A/CA, mediante evaluación con el método del gradiente y el de las heteroforias. El A/CA promedio con el método del gradiente y de las heteroforias fue de 1:3.15 y 1:4.89 respectivamente

Bisphenol A Mineralization by Integrated Ultrasound-UV-Iron (II) Treatment

ABSTRACT: Bisphenol A (BPA), an organic compound largely used in the plastic industry as a monomer for production of epoxy resins and polycarbonate, is an emerging contaminant that is released in the environment from bottles and packaging. BPA degradation (118 μmol L-1) under sonochemical conditions was investigated in this study, using a 300 kHz frequency, with a 80 W electrical power. Under these conditions, BPA was eliminated by the ultrasound process (∼90 min). However, even after long ultrasound irradiation periods (10 h), more than 50% of chemical oxygen demand (COD) and 80% of total organic carbon (TOC) remained in the solution, indicating that most BPA intermediates are recalcitrant toward ultrasonic action. Accumulation of hydrogen peroxide from °OH and °OOH radical recombination was also observed. To increase the efficiency of BPA treatment, experiments combined ultrasound with Fe2+ (100 μmol L-1) and/or UV radiation (254 nm):  Ultrasound/UV; Ultrasound/Fe2+; Ultrasound/UV/Fe2+. Both UV and Fe2+ induced hydrogen peroxide dissociation, leading to additional °OH radicals and complete COD and TOC removal. Thus difficulties in obtaining mineralization of micropollutants like BPA through ultrasonic action alone, can be overcome by the Ultrasound/UV/Fe2+ combination. Moreover, this technique was found to be the most cost-effective one. So, the integrated ultrasound-UV-iron(II) process was shown to be of interest for the treatment of wastewaters contaminated with BP

Intelligent fault detection system for microgrids

The dynamic features of microgrid operation, such as on-grid/off-grid operation mode, the intermittency of distributed generators, and its dynamic topology due to its ability to reconfigure itself, cause misfiring of conventional protection schemes. To solve this issue, adaptive protection schemes that use robust communication systems have been proposed for the protection of microgrids. However, the cost of this solution is significantly high. This paper presented an intelligent fault detection (FD) system for microgrids on the basis of local measurements and machine learning (ML) techniques. This proposed FD system provided a smart level to intelligent electronic devices (IED) installed on the microgrid through the integration of ML models. This allowed each IED to autonomously determine if a fault occurred on the microgrid, eliminating the requirement of robust communication infrastructure between IEDs for microgrid protection. Additionally, the proposed system presented a methodology composed of four stages, which allowed its implementation in any microgrid. In addition, each stage provided important recommendations for the proper use of ML techniques on the protection problem. The proposed FD system was validated on the modified IEEE 13-nodes test feeder. This took into consideration typical features of microgrids such as the load imbalance, reconfiguration, and off-grid/on-grid operation modes. The results demonstrated the flexibility and simplicity of the FD system in determining the best accuracy performance among several ML models. The ease of design’s implementation, formulation of parameters, and promising test results indicated the potential for real-life applications

Photocatalytic disinfection treatments: Viability, cultivability and metabolic changes of e. Coli using diferent mesurements methods

In this work, the oxidative stress was produced by the illumination of either fi xed TiO2 or suspended TiO2, and the relation between cultivability and viability under oxidative conditions was studied using a Direct Viable Count (DVC) and Fluorescence In Situ Hybridisation (FISH) methods. Under certain oxidative conditions simulating incomplete treatments, viable cells that had lost their cultivability were observed to recover all of their physiological functions when transferred to fresh nutrient media. Moreover, alterations in the nutrient assimilation processes were studied by 1H-NMR during and after the photocatalytic treatment. This allowed us to shed some light on how the damage chain propagates during the treatment. This work demonstrate that the Standard Plate Count (SPC) method commonly used to estimate the c ell populations during disinfection processes is ill adapted, whereas the FISH-DVC pair offers a reliable alternativeEn este trabajo, el estrés oxidativo producido con radiación en presencia TiO2 fijo o suspendido TiO2, y la relación entre cultivabilidad y viabilidad se han realizado, utilizando recuento directo de células viables (CDV) y fluorescencia de hibridación in situ (FISH). Se encontró que cuando el tratamiento es incompleto, las células viables que habían perdido su cultivabilidad pueden recuperar todas sus funciones fisiológicas, cuando son transferidas a un nuevo medio nutritivo. Por otra parte, las alteraciones en los procesos de asimilación de nutrientes fueron estudiados por 1H-RMN durante y después del tratamiento fotocatalítico. Esto permitió tener indicios sobre cómo se propaga la cadena de daños durante el tratamiento. Se demostró que el recuento en placa comúnmente usado para estimar la población de E coli en los procesos de desinfección no sería confiable, mientras que el método combinado FISH-DVC ofrece una alternativa fiabl

Relación acomodación convergencia por acomodación (AC/A) con el método del gradiente en un pequeño grupo poblacional de la ciudad de Pereira

The purpose of this study was to determine the average value of the relation AC/A estimated with the gradient method in a small population group of Pereira and to establish the most appropriate stimulus lens to calculate such synergy. Methods: 66 people were evaluated between 16 and 30 years old who had the following examination: inter pupilary distance, visual acuity, heterophories, near vision, far vision, induced phories, and AC/A gradient. Results: an AC/A gradient of 1:3,12 (SD =1.30) was obtained; with an stimulus lens of +1.00, 1:3,41 (SD = 1,59), -1.00 D 1:2,82 (SD = 1,45), -2.00 D, 1:3,11 (SD =1,27), y -3.00 D, 1:3,18 (SD =1,27). The best correlation was obtained with lenses -2.00 and -3.00 D (SD =0.76) and the worst with lenses +1.00 and -1.00 D (SD =0.15). Conclusions: the relation AC/A gradient was lower than the reported in literature and there was a significant variability when it was measured with different stimulus lenses.El propósito de este estudio fue determinar el valor promedio de la relación AC/A calculada con el método del gradiente en un pequeño grupo poblacional de la ciudad de Pereira y establecer el lente estímulo más pertinente para calcular esta sinergia. Metodología: se evaluaron 66 personas con edades entre 16 y 30 años, a los cuales se realizó: distancia interpupilar, agudeza visual, heteroforias visión lejana (VL) y visión próxima (VP), forias inducidas y AC/A gradiente. Resultados: se obtuvo un AC/A gradiente de 1:3,12 (SD =1.30); con el lente estímulo de +1.00, 1:3,41 (SD = 1,59), -1.00 D 1:2,82 (SD = 1,45), -2.00 D, 1:3,11 (SD =1,27), y -3.00 D, 1:3,18 (SD =1,27). La mejor correlación se obtuvo con los lentes de -2.00 y -3.00 D (SD =0.76) y la peor con los lentes de +1.00 y -1.00 D (SD =0.15). Conclusiones: la relación AC/A gradiente es menor a la reportada en la literatura y existe una significativa variabilidad al ser medida con diferentes lentes estímulo

Estudio para la ubicación de equipos detectores de falla en el sistema eléctrico de distribución

Se presenta la localización de fallas en el sistema eléctrico de distribución, combinando los métodos de onda viajera y transformada de Wavelet para el cálculo de la distancia de falla. Se analizan los resultados para proponer la instalación de indicadores de falla mediante los métodos de Elbow y K-means, la instalación de estos equipos permite obtener una ubicación de falla precisa.The localization of faults in the electrical distribution system is presented, combining the traveling wave and Wavelet transform methods for the calculation of the fault distance. The results are analyzed to propose the installation of fault indicators using the Elbow and K-means methods. The installation of this equipment allows to obtain an accurate fault location

Comparative behavior of relevant micropollutants in different water matrices by uv254 and simulated solar light irradiation and neutral photo-fenton process

This is a comparative study of photolytic degradation under exposure to UV254 nm and solar-simulator irradiation of a mixture of eight equally concentrated relevant micropollutants (atenolol, benzotriazole, clarithromycin, gabapentin, methylbenzotriazole, metformin, metoprolol and primidone; 2 µM of each compound) in the presence of H2O2 and Fe(II) in ultrapure water, Lake Geneva water, and effluent from a wastewater treatment plant (WWTP). The results indicate that the oxidation rate increased in the presence of low-concentration H2O2 and Fe(II), except for metformin and methylbenzotriazole. Fenton and photo-Fenton employing sunlight simulation reached low micropollutant removal rates. The water matrix plays an important role on photodegradation reaction yields

Degradation of emergent contaminants by UV, UV/H2O2 and neutral photo-fenton at pilot scale in a domestic wastewater treatment plant

This study focuses on the removal of 22 selected micropollutants in an effluent from a municipal wastewater treatment plant (MWTP) at pilot scale. A reactor of 37 L with five low pressure mercury lamps emitting at 254 nm (UV254) was used. The 22 micropollutants include 15 pharmaceuticals, 2 X-Ray contrast medias, 1 corrosion inhibitor and 4 biocides/pesticides. Five of these 22 compounds were used as indicative substances as proposed by the Swiss Federal Office for the Environment (FOEN) (carbamazepine, diclofenac, sulfamethoxazole, benzotriazole and mecoprop). Treatments included UV254 light alone, UV254+H2O2 and UV254+H2O2+Fe3+. Wastewater coming from the MWTP already contained iron with an average total iron of 1.6 mg L-1. Original pH was not modified and remained between 6 and 7. The parameters changed during the experiments to find the optimal conditions were: wastewater flow rate (2-14 m3 h-1), H2O2 concentration (20-50 mg L-1) and Fe (III) concentration (0-4 mg L-1). Chemicals removal rates were greater than 80% for the majority of the flow rates tested. Operating costs for the different conditions evaluated were also estimated and compared

Adaptive Impedance-Based Fault Location Algorithm for Active Distribution Networks

Modern fault location methods are robust; however, they depend strongly on the availability of the measurements given by Distributed Energy Resources (DER). If the communication or synchronism of this information is lost, the fault location is not possible. This paper proposes an adaptive impedance-based fault location algorithm for active distribution systems. The proposal combines information provided by Intelligent Electronic Devices (IEDs) located at the substation, the knowledge of the network topology and parameters, as well as the distributed power sources, to estimate the fault location. Its adaptive feature is given by the use of a Distributed Energy Resources (DER) electrical model. This model is used to estimate the DER current contribution to the fault, in case the information provided by a local IED is not available. The method takes two types of DER technologies into account: Inverter non-interfaced DER (INIDER) and Inverter-interfaced DER (IIDER). The proposed method is validated on a modified IEEE 34-node test feeder, which was simulated with ATP/EMTP. The results obtained using the IEDs information, presented a maximum error of 0.8%. When this information is not available, the method’s performance decreases slightly, obtaining a maximum error of 1.1%. The proposed method showed better performance when compared with two state of the art methods, indicating potential use for real-life applications