Ultrasonic radiation influence on the bioadsorbent characteristics of citrus (citrus x lemon) & (citrus x sinensis)

Of all the materials used as adsorbents, activated charcoal is the most popular as it is excellent for reducing/eliminating a wide variety of contaminants. This capacity is mainly due to its structural characteristics that give it a large surface area. However, it has several disadvantages. The most important are that the adsorbent material is quite expensive as is its regeneration. For this reason, more economical absorbents have been sought, highlighting the study of adsorption phenomena in some types of biomass as adsorbents. Bioadsorption is considered a viable alternative to the physical-chemical methods currently used for the recovery or removal of heavy metals dissolved in liquid effluents. Its main attraction, from an industrial point of view, is its low cost due to the great abundance, easy to obtain and low price of the bioadsorbent material. Bioadsorption is very effective in treating metal concentrations below 100 mg/L, where the application of physical-chemical methods is neither technically nor economically feasible. One of these materials of interest is citrus peels, because, due to their abundance as a waste product of the food industries, they are hardly reused and currently have little economic value. However, these residues have a low adsorption capacity, so both physical and chemical modifications are required to increase their adsorption properties. This study compares the characteristics of orange and lemon peels undergoing a physical-chemical treatment with ultrasonic radiation assistance and the optimization of experimental conditions to obtain useful bioadsorbents in discontinuous processes (batch)Postprint (published version

Understanding the performance increase of catalysts supported on N-functionalized carbon in PEMFC catalyst layers

Applying nitrogen-modified carbon support in PEMFCs has been attracting arising interest due to the resulting performance enhancement. In the present study, we attempt to uncover the origin and gain a deeper understanding of the different N-modification processes, whose influences are responsible for the performance improvement. By utilizing chemically modified Ketjenblack supports comprising altered fraction of N-functionalities, we investigate the underlying mechanism of the drastically reduced voltage losses under fuel cell operation conditions. In all, we demonstrate the key role of support modification induced by ammonia in strengthened support/ionomer interactions and alter physico-chemical properties of the carbon support contributing towards enhanced MEA performance. With the use of X-ray photoelectron spectroscopy (XPS), we show unambiguous evidences that not all N modified surfaces yield the desired performance increase. Rather, the latter depends on a complex interplay between different electrochemical parameter and catalyst properties. We want to emphasize the ionomer/support interaction as one important factor for enhanced ionomer distribution and present a prove of a direct interaction between the ionomers´ sidechains and N-functional groups of the support

Assessment of the water chemical quality improvement based on human health risk indexes: Application to a drinking water treatment plant incorporating membrane technologies

A methodology has been developed in order to evaluate the potential risk of drinking water for the health of the consumers. The methodology used for the assessment considered systemic and carcinogenic effects caused by oral ingestion of water based on the reference data developed by the World Health Organisation (WHO) and the Risk Assessment Information System (RAIS) for chemical contaminants. The exposure includes a hypothetical dose received by drinking this water according to the analysed contaminants. An assessment of the chemical quality improvement of produced water in the Drinking Water Treatment Plant (DWTP) after integration of membrane technologies was performed. Series of concentration values covering up to 261 chemical parameters over 5 years (2008–2012) of raw and treated water in the Sant Joan Despí DWTP, at the lower part of the Llobregat River basin (NE Spain), were used. After the application of the methodology, the resulting global indexes were located below the thresholds except for carcinogenic risk in the output of DWTP, where the index was slightly above the threshold during 2008 and 2009 before the upgrade of the treatment works including membrane technologies was executed. The annual evolution of global indexes showed a reduction in the global values for all situations: HQ systemic index based on RAIS dropped from 0.64 to 0.42 for surface water and from 0.61 to 0.31 for drinking water; the R carcinogenic index based on RAIS was negligible for input water and varied between 4.2 × 10- 05 and 7.4 × 10- 06 for drinking water; the W systemic index based on the WHO data varied between 0.41 and 0.16 for surface water and between 0.61 and 0.31 for drinking water. A specific analysis for the indexes associated with trihalomethanes (THMs) showed the same pattern.Peer ReviewedPostprint (author's final draft

Estado bucodental en gestantes de la ciudad de Armenia, Colombia.

Objetivo: La salud bucodental en las gestantes es hoy por hoy un tema de mucha relevancia social cultural y académica, por todos los procesos y cambios que intervienen y se manifiestan en este estado, igualmente la salud bucodental hace parte esencial del bienestar que se debe tener en la gestación para un desarrollo y resultado exitoso de este proceso, por eso el objetivo de este estudio fue determinar el estado bucodental de las gestantes de Armenia. Materiales y Métodos: Se realizo un estudio observacional descriptivo de corte transversal, en el municipio de Armenia (Quindío), se tomaron las gestantes que asisten al control prenatal en la Red de salud del municipio, se incluyeron en total 186 gestantes que cumplieron con los criterios de selección y desearon participar voluntariamente en la investigación. Resultados: El promedio de edad fue de 22 años, la mayoría (58.3%) con procedencia del Quindío, El 65.9% (122) habían visitado al odontologo durante la actual gestación, Al examen clínico se encontró en el 34.59% de las gestantes presentaban lesiones en tejidos blandos, el 94.05% caries y el 70.27% enfermedad periodontal. Conclusiones: El estado de salud bucodental en las gestantes es alterado con prevalencias altas de enfermedades como caries que se puede decir que es una enfermedad que existe antes de la gestación y adicionalmente la asistencia a consulta odontológica dentro de época de gestación no es en la proporción ideal a las necesidades evidenciadas

Revealing the CO Coverage Driven C-C Coupling Mechanism for Electrochemical CO₂ Reduction on Cu₂O Nanocubes via Operando Raman Spectroscopy

Electrochemical reduction of carbon dioxide (CO2RR) is an attractive route to close the carbon cycle and potentially turn CO2 into valuable chemicals and fuels. However, the highly selective generation of multicarbon products remains a challenge, suffering from poor mechanistic understanding. Herein, we used operando Raman spectroscopy to track the potential-dependent reduction of Cu2O nanocubes and the surface coverage of reaction intermediates. In particular, we discovered that the potential-dependent intensity ratio of the Cu–CO stretching band to the CO rotation band follows a volcano trend similar to the CO2RR Faradaic efficiency for multicarbon products. By combining operando spectroscopic insights with Density Functional Theory, we proved that this ratio is determined by the CO coverage and that a direct correlation exists between the potential-dependent CO coverage, the preferred C–C coupling configuration, and the selectivity to C2+ products. Thus, operando Raman spectroscopy can serve as an effective method to quantify the coverage of surface intermediates during an electrocatalytic reaction

Evaluación de sistema de control interno para mejora la toma de decisiones de la Sub Dirección de Administración y Finanzas del colegio Ricardo Tello de La Molina, como institución sin fines de lucro en los años 2015 y 2016

El presente trabajo de investigación tiene como principal objetivo proponer lineamientos en el sistema de control interno que permita una mejor toma de decisiones en la Sub Dirección de Administración y Finanzas del Colegio Ricardo Tello, entidad educativa con 123 años de vida institucional. Para la investigación se utilizó el diseño no experimental haciendo uso de los métodos inductivo, deductivo, análisis y síntesis, que nos permitió observar y analizar a la Entidad Educativa, así también se utilizó la técnica de la Encuesta con el objeto de identificar las debilidades y fortalezas que la entidad presenta. Esta encuesta así como el FODA y el cuestionario basado en los principios del COSO 2013, nos fue de utilidad para lograr determinar el modo que influye la evaluación del sistema de control interno en la toma de decisiones y poder disminuir los riesgos encontrados.Trabajo de suficiencia profesionalCampus Lima Centr

Operando Investigation of Ag‐Decorated Cu₂O Nanocube Catalysts with Enhanced CO₂ Electroreduction toward Liquid Products

Direct conversion of carbon dioxide into multicarbon liquid fuels by the CO2 electrochemical reduction reaction (CO2RR) can contribute to the decarbonization of the global economy. Here, well‐defined Cu2O nanocubes (NCs, 35 nm) uniformly covered with Ag nanoparticles (5 nm) were synthesized. When compared to bare Cu2O NCs, the catalyst with 5 at% Ag on Cu2O NCs displayed a two‐fold increase in the Faradaic efficiency for C2+ liquid products (30% at ‐1.0 VRHE), including ethanol, 1‐propanol, and acetaldehyde, while formate and hydrogen were suppressed. Operando X‐ray absorption spectroscopy revealed the partial reduction of Cu2O during CO2RR, accompanied by a reaction‐driven redispersion of Ag on the CuOx NCs. Operando surface‐enhanced Raman spectroscopy data further uncovered significant variations in the CO binding to Cu, which were assigned to Ag‐Cu sites formed during CO2RR that appear crucial for the C‐C coupling and the enhanced yield of liquid products

Profitability Assessment of Windfarm Overplanting in Spain

The efforts made by European institutions to decarbonise the electricity system over the last decade have led Spain to become the fifth country in the world in terms of wind power plant capacity in 2021. This major achievement is still far from being able to contain and limit CO2 emissions. By 2030, it is expected that, together with photovoltaic energy, Spain will reach 74 % of renewable generation in its electricity system. Wind technology is currently very mature in onshore wind farms and its relatively low cost makes this technology attractive to investors. However, the best wind sites were the first places to be occupied by the first turbine generations. On the other hand, newer wind farms occupy sites with less wind resource but have more efficient turbines. To improve the profitability of the wind farm and increase its production, the feasibility of other alternatives such as overplanting or storage is beginning to be investigated. Overplanting aims to optimise the use of the transmission system by increasing wind capacity above the transmission capacity limit. In this work, we measure the profitability of an overplanting strategy by quantifying the parameters that make profitable the investment. The developed model optimised the production of energy taking into account technical and financial parameters in order to cover a wide range of situations. We analysed the case of a specific site with 25 2 MW turbines with the Python tool PyWake. The results obtained show that for each new turbine the annual energy produced (AEP) grows by around 3.87 GWh per turbine added (a cut of 1.69 GWh due to congestion of the transmission system). The study shows improvements in profitability when the electricity price exceeds 70 €/MWh

Operando‐Untersuchung von Ag‐dekorierten Cu₂O‐Nanowürfel‐Katalysatoren mit verbesserter CO₂‐Elektroreduktion zu Flüssigprodukten

Direct conversion of carbon dioxide into multicarbon liquid fuels by the CO2 electrochemical reduction reaction (CO2RR) can contribute to the decarbonization of the global economy. Here, well‐defined Cu2O nanocubes (NCs, 35 nm) uniformly covered with Ag nanoparticles (5 nm) were synthesized. When compared to bare Cu2O NCs, the catalyst with 5 at% Ag on Cu2O NCs displayed a two‐fold increase in the Faradaic efficiency for C2+ liquid products (30% at ‐1.0 VRHE), including ethanol, 1‐propanol, and acetaldehyde, while formate and hydrogen were suppressed. Operando X‐ray absorption spectroscopy revealed the partial reduction of Cu2O during CO2RR, accompanied by a reaction‐driven redispersion of Ag on the CuOx NCs. Operando surface‐enhanced Raman spectroscopy data further uncovered significant variations in the CO binding to Cu, which were assigned to Ag‐Cu sites formed during CO2RR that appear crucial for the C‐C coupling and the enhanced yield of liquid products