Sustainability and New Technologies

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A Novel Cooperative Controller for Inverters of Smart Hybrid AC/DC Microgrids

This paper presents a novel cooperative control technique concerning fully-distributed AC/DC microgrids. Distributed generation based on inverters has two types, i.e., Current Source Inverter (CSI), also referred to as PQ inverter, and Voltage Source Inverter (VSI). Both inverter forms have a two-layer coordination mechanism. This paper proposes a design method for the digital Proportional-Resonant (PR) controller that regulates the current inside an inverter. The inverters will improve the voltage quality of the microgrid while maintaining the average voltage of buses at the same desired level. There is comprehensive detail on the computations specific to resonant and proportional gains and digital resonance path coefficients. The paper includes a digital PR controller design and its analysis in the frequency domain. The analysis is based on the w-domain. The main contribution of this paper is the proposed method, which not only focuses on the transient response but also improves the steady-state response which smoothens the voltage; furthermore, all inverters are effectively involved to increase the capacity of the microgrid for better power management. The suggested cooperative control technique is used on an IEEE 14-bus system having fully distributed communication. The convincing outcomes indicate that the suggested control technique is an effectual means of regulating the microgrid’s voltage to obtain an evener and steady voltage profile. The microgrid comprises distributed resources and is used as the primary element to analyse power flow and quality indicators associated with a smart grid. Lastly, numerical simulation observations are utilised for substantiating the recommended algorithm

A novel smart energy management as a service over a cloud computing platform for nanogrid appliances

There will be a dearth of electrical energy in the world in the future due to exponential increase in electrical energy demand of rapidly growing world population. With the development of Internet of Things (IoT), more smart appliances will be integrated into homes in smart cities that actively participate in the electricity market by demand response programs to efficiently manage energy in order to meet this increasing energy demand. Thus, with this incitement, the energy management strategy using a price-based demand response program is developed for IoT-enabled residential buildings. We propose a new EMS for smart homes for IoT-enabled residential building smart devices by scheduling to minimize cost of electricity, alleviate peak-to-average ratio, correct power factor, automatic protective appliances, and maximize user comfort. In this method, every home appliance is interfaced with an IoT entity (a data acquisition module) with a specific IP address, which results in a wide wireless system of devices. There are two components of the proposed system: software and hardware. The hardware is composed of a base station unit (BSU) and many terminal units (TUs). The software comprises Wi-Fi network programming as well as system protocol. In this study, a message queue telemetry transportation (MQTT) broker was installed on the boards of BSU and TU. In this paper, we present a low-cost platform for the monitoring and helping decision making about different areas in a neighboring community for efficient management and maintenance, using information and communication technologies. The findings of the experiments demonstrated the feasibility and viability of the proposed method for energy management in various modes. The proposed method increases effective energy utilization, which in turn increases the sustainability of IoT-enabled homes in smart cities. The proposed strategy automatically responds to power factor correction, to protective home appliances, and to price-based demand response programs to combat the major problem of the demand response programs, which is the limitation of consumer’s knowledge to respond upon receiving demand response signals. The schedule controller proposed in this paper achieved an energy saving of 6.347 kWh real power per day, this paper achieved saving 7.282 kWh apparent power per day, and the proposed algorithm in our paper saved $2.3228388 per day

Scour prediction and scour protections in offshore wind farms

This paper is the result of research whose main objective is to analyse different methods used for the prediction of maximum scour depth and scour extension, and for the design of scour protections in offshore wind farms located in shallow water, using medium and large diameter monopile foundations. Physical agents such as waves, currents and wind play a major role in the design of structures like offshore farms. As a result, the study has highlighted the need for introducing experience backed climate monomials such as the dimensionless wave height parameter (H0) and proposes the use of formulations that can express the extent of scour protections as a function of waves in transitional waters

Small area estimation of average compositions under multivariate nested error regression models

[Abstract]: This paper investigates the small area estimation of population averages of unit-level compositional data. The new methodology transforms the compositions into vectors of Rm and assumes that the vectors follow a multivariate nested error regression model. Empirical best predictors of domain indicators are derived from the fitted model, and their mean squared errors are estimated by parametric bootstrap. The empirical analysis of the behavior of the introduced predictors is investigated by means of simulation experiments. An application to real data from the Spanish household budget survey is given. The target is to estimate the average of proportions of annual household expenditures on food, housing and others, by Spanish provinces.Generalitat Valenciana; Prometeo/2021/063Xunta de Galicia; ED431C 2020/14Xunta de Galicia; ED431G 2019/01Axencia Galega de Innovación; COV20/00604Supported by the Instituto Galego de Estatística, by the Grants PGC2018-096840-B-I00 and PID2020-113578RB-I00 of the Spanish Ministerio de Economía y Competitividad, by the Grant Prometeo/2021/063 of the Generalitat Valenciana, and by the Xunta de Galicia (Grupos de Referencia Competitiva ED431C 2020/14), and by GAIN (Galician Innovation Agency) and the Regional Ministry of Economy, Employment and Industry Grant COV20/00604 and Centro de Investigación del Sistema Universitario de Galicia ED431G 2019/01, all of them through the ERDF

Evaluación de las propiedades probióticas de bacterias lácticas de origen enológico

[ES]: En este trabajo se ha evaluado la resistencia a la saliva, al medio ácido y a las sales biliares de once cepas de origen enológico pertenecientes a Lactobacillus spp., Pediococcus spp., y Oenococcus oeni, además de dos cepas probióticas de referencia. Las cepas de Lactobacillus y Pediococcus mostraron una alta resistencia a la lisozima (> 80 %), y todas sobrevivieron a las sales biliares y a bajos valores de pH (pH 1.8), lo que sugiere una buena adaptación de estas cepas a las condiciones gastrointestinales. También se evaluó su capacidad para adherirse a la mucosa intestinal y para inhibir la adhesión de Escherichia coli a células epiteliales del intestino. En particular, la cepa P. pentosaceus cIAL-86 mostró un alto porcentaje de adherencia a las células intestinales (> 12 %), incluso superior al mostrado por las cepas probióticas de referencia, y una alta actividad anti-adhesión de E. coli cIAL-153 (> 30 %).[EN]: In this study, the saliva, acid and bile resistance of eleven enological strains of Lactobacillus spp., Pediococcus spp., and Oenococcus oeni, as well as two probiotic reference strains were evaluated. Lactobacillus and Pediococcus strains showed high resistance to lysozyme (> 80 %) and all were capable of surviving at bile salts and low pH values (pH 1.8), suggesting a good adaptation to gastrointestinal conditions. The ability of these strains to adhere to the intestinal mucosa and the inhibition of the adhesion of Escherichia coli to intestinal cells were also evaluated. In particular, P. pentosaceus cIAL-86 showed a high percentage of adhesion to intestinal cells (> 12 %), even higher than that shown by the reference probiotic strains, and a high anti-adhesion activity against E. coli cIAL-153 (> 30 %).Este trabajo ha sido financiado por el Ministerio de Economía y Competitividad (Proyectos AGL2012-04172-C02-01, PRI-PIBAR-2011-1358 y Consolider Ingenio 2010 FUN-C-FOOD CSD2007-00063), la Comunidad Autónoma de Madrid (ALIBIRD P2009/AGR-1469) y el INIA (proyecto RM2011-00003-00-00). A. García Ruiz es beneficiaria de una beca del Instituto DanonePeer Reviewe

Field campaign on pressure on the crown wall at the outer port of Punta Langosteira breakwater

[Abstract:] Punta Langosteira port, located in A Coruña (Spain), was monitored during the winters of 2017 and 2018, measuring wave pressure in the crown wall structure. Furthermore, the metocean variables were measured on a buoy located very close to the breakwater. This paper presents the real pressures measured at the crown wall of the breakwater during different storm events. These values are compared with the results of the application of state-of-the-art equations for the calculation of pressures on crown walls. The results obtained show the behaviour of the pressures with a crown wall fully protected by the armour, as is the case of Langosteira breakwater. Finally, several conclusions are made on the methodology for measuring the pressures using physical models and the relevance of the armour roughness.Fundação para a Ciência e a Tecnologia (FCT); PTDC/ECI-EGC/31090/201

Anti-adhesive activity of cranberry phenolic compounds and their microbial-derived metabolites against uropathogenic Escherichia coli in bladder epithelial cell cultures

This is an open access article distributed under the Creative Commons Attribution License.-- This article belongs to the Special Issue Phenolics and Polyphenolics 2015.Cranberry consumption has shown prophylactic effects against urinary tract infections (UTI), although the mechanisms involved are not completely understood. In this paper, cranberry phenolic compounds and their potential microbial-derived metabolites (such as simple phenols and benzoic, phenylacetic and phenylpropionic acids) were tested for their capacity to inhibit the adherence of uropathogenic Escherichia coli (UPEC) ATCC®53503™ to T24 epithelial bladder cells. Catechol, benzoic acid, vanillic acid, phenylacetic acid and 3,4-dihydroxyphenylacetic acid showed anti-adhesive activity against UPEC in a concentration-dependent manner from 100-500 µM, whereas procyanidin A2, widely reported as an inhibitor of UPEC adherence on uroepithelium, was only statistically significant (p < 0.05) at 500 µM (51.3% inhibition). The results proved for the first time the anti-adhesive activity of some cranberry-derived phenolic metabolites against UPEC in vitro, suggesting that their presence in the urine could reduce bacterial colonization and progression of UTI.This work was funded by the Ministry of Economy and Competitiveness (MINECO) (Projects AGL-2010-17499 and AGL2012-40172-C02-01) and the Comunidad Autónoma de Madrid (Project ALIBIRD S2013/ABI-2728), Spain. Adelaida Esteban-Fernández would like to thank the MINECO-FPI program for her research contract.We acknowledge the support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).Peer Reviewe

Eficiencia en el sector de las energías renovables: la energía hidroeléctrica y eólica

El presente trabajo comienza con un análisis del contexto mundial y nacional del sector de las energías renovables, centrándose especialmente en las energías hidroeléctricas y eólicas. Para llevar a cabo el análisis se presentan los principales datos económicos de la industria, su estructura y la localización geográfica de la producción. A continuación, se han extraído los datos de las empresas hidroeléctricas y eólicas a través de la base SABI y se han calculado sus índices de eficiencia a través de la estimación del modelo no paramétrico DEA. Además, una vez obtenidos estos índices, se ha realizado un estudio econométrico para obtener conclusiones acerca de la influencia de las variables “tamaño de la empresa” y “localización geográfica” en la eficiencia de las empresas. En base a los resultados obtenidos se llega a la conclusión de que las empresas hidroeléctricas de mayor tamaño y que pertenecen a Aragón son más eficientes, mientras que las empresas eólicas más eficientes son de tamaño medio y el hecho de pertenecer a Aragón no influye sobre sus índices de eficiencia.<br /

La eficiencia en el sector asegurador español: Tamaño empresarial y número de empleados

El objetivo del presente trabajo es analizar la eficiencia del sector asegurador español. Utilizando la metodología DEA, una frontera de producción determinista y la información obtenida de la base de datos de SABI, obtenemos los índices de eficiencia de cada una de las empresas del sector, desde el punto de vista del input. Esto nos permite identificar las empresas más y menos eficientes del sector. A continuación, a través de unos sencillos modelos econométricos analizamos en qué medida afectan las variables 'ingresos de explotación', 'tamaño empresarial' y 'número de empleados' afectan a la eficiencia de las empresas del sector. <br /