A virtual power plant model for time-driven power flow calculations

This paper presents the implementation of a custom-made virtual power plant model in OpenDSS. The goal is to develop a model adequate for time-driven power flow calculations in distribution systems. The virtual power plant is modeled as the aggregation of renewable generation and energy storage connected to the distribution system through an inverter. The implemented operation mode allows the virtual power plant to act as a single dispatchable generation unit. The case studies presented in the paper demonstrate that the model behaves according to the specified control algorithm and show how it can be incorporated into the solution scheme of a general parallel genetic algorithm in order to obtain the optimal day-ahead dispatch. Simulation results exhibit a clear benefit from the deployment of a virtual power plant when compared to distributed generation based only on renewable intermittent generation.Peer ReviewedPostprint (published version

Reliability analysis of distribution systems with photovoltaic generation using a power flow simulator and a parallel Monte Carlo approach

This paper presents a Monte Carlo approach for reliability assessment of distribution systems with distributed generation using parallel computing. The calculations are carried out with a royalty-free power flow simulator, OpenDSS (Open Distribution System Simulator). The procedure has been implemented in an environment in which OpenDSS is driven from MATLAB. The test system is an overhead distribution system represented by means of a three-phase model that includes protective devices. The paper details the implemented procedure, which can be applied to systems with or without distributed generation, includes an illustrative case study and summarizes the results derived from the analysis of the test system during one year. The goal is to evaluate the test system performance considering different scenarios with different level of system automation and reconfiguration, and assess the impact that distributed photovoltaic generation can have on that performance. Several reliability indices, including those related to the impact of distributed generation, are obtained for every scenario.Postprint (published version

Perceptions and Acceptance of Desalinated Seawater for Irrigation: A Case Study in the Níjar District (Southeast Spain)

In the context of increasing demand for irrigation water—but, at the same time, with the constraints in the supply from traditional resources—desalinated seawater has been recognized as one of the alternative sources of water to increase the supply for agricultural irrigation. However, its use among farmers has not yet started to expand. Policy makers need to understand what is causing the low acceptance levels of farmers, and how their attitudes could be improved. This is the first study that has conducted an analysis of farmers’ perceptions and acceptance of the use of desalinated seawater for irrigation. The study is based on collected data from a survey completed by farmers in southeastern Spain who do not use desalinated seawater. The main results indicate that desalinated seawater as a water supply source has the lowest acceptance level for farmers. Barriers for its use are price, the need for additional fertilization, and the perception that it would negatively affect the yield and crop quality. The farmers’ general level of knowledge about the impact of using desalinated seawater in agriculture is extremely low. Furthermore, farmers consider it a priority that their startup investment should be subsidized and that water prices should be reduced. Based on the study findings, this paper makes recommendations for the decision-making process in order to improve farmers’ acceptance levels

A Solid State Transformer model for power flow calculations

This paper presents the implementation of a Solid State Transformer (SST) model in OpenDSS. The goal is to develop a SST model that could be useful for assessing the impact that the replacement of the conventional iron-and-copper transformer with the SST can have on the distribution system performance. Test distribution systems of different characteristics and size have been simulated during different time periods. The simulations have been carried out assuming voltage-dependent loads and considering that power flow through either the HV/MV substation transformer or any of the MV/LV distribution transformers can be bidirectional. Simulation results prove that a positive impact should be expected on voltages at both MV and LV levels, but the efficiency of current SST designs should be improved.Postprint (author's final draft

Current-driven domain wall motion along ferromagnetic strips with periodically-modulated perpendicular anisotropy

The dynamics of magnetic domain walls along ferromagnetic strips with spatially modulated perpendicular magnetic anisotropy is theoretically studied by means of micromagnetic simulations. Ferromagnetic layers with a periodic sawtooth profile of the anisotropy depict a well-defined set of energy minima where the walls are pinned in the absence of external stimuli, and favor the unidirectional propagation of domain walls. The performance of the current-driven domain wall motion along these ratchet-like systems is compared to the field-driven case. Our study indicates that the current-driven domain wall motion exhibits significant improvements with respect to the field-driven case in terms of bit shifting speed and storage density, and therefore, it is suggested for the development of novel devices. The feasibility of these current-driven ratchet devices is studied by means of realistic micromagnetic simulations and supported by a one-dimensional model updated to take into account the periodic sawthooth anisotropy profile. Finally, the current-driven domain wall motion is also evaluated in systems with a triangular modulation of the anisotropy designed to promote the bidirectional shifting of series of walls, a functionality that cannot be achieved by magnetic fields.Comment: 32 pages, 11 figure

An approximation to the prediction of the summery emergence of "Ochlerotatus caspius" (Diptera: Culicidae) based on the relationship between degree-days accumulations and adult captures

Ochlerotatus caspius (Pallas) (Diptera, Culicidae) es el culícido más abundante durante el verano en las marismas de Huelva. Este estudio demuestra que la relación entre capturas de adultos, convertidas en probit, y la acumulación de temperatura o número de días-grado, convenientemente adaptada mediante a una transformación logarítmica, muestra ser signifi cativamente lineal para cada generación de este mosquito a lo largo de cada verano. Además, si se procesan todos los datos disponibles de todos los años considerados en el estudio se obtiene una alta correlación lineal y, en consecuencia, las ecuaciones resultantes poseen valor predictivo. Los resultados de la validación de los pronósticos que se extraen de las rectas de regresión log-probit, permiten que se puedan considerar estas rectas como una herramienta más de cara a aumentar la efi cacia de los programas de control integrado que se llevan a cabo en esta zona.Predicción de la emergencia estival de Ochlerotatus caspius (Diptera: Culicidae) basada en la relación entre la acumulación de días-grado y la captura de adultos. Ochlerotatus caspius (Pallas) (Diptera, Culicidae) es el culícido más abundante durante el verano en las marismas de Huelva. Este estudio demuestra que la relación entre capturas de adultos, convertidas en probit, y la acumulación de temperatura o número de días-grado, convenientemente adaptada mediante a una transformación logarítmica, muestra ser signifi cativamente lineal para cada generación de este mosquito a lo largo de cada verano. Además, si se procesan todos los datos disponibles de todos los años considerados en el estudio se obtiene una alta correlación lineal y, en consecuencia, las ecuaciones resultantes poseen valor predictivo. Los resultados de la validación de los pronósticos que se extraen de las rectas de regresión log-probit, permiten que se puedan considerar estas rectas como una herramienta más de cara a aumentar la efi cacia de los programas de control integrado que se llevan a cabo en esta zona

Reduced kinetic mechanisms for modelling LPP combustión in gas turbines

Reduced kinetic mechanisms for modelling LPP combustión in gas turbine

The Situation of Management Research in Peru. A Bibliometric Analysis in the Bicentennial

In 2021, Peru celebrated 200 years of independence, marking an important milestone in its history, which leads us to the following question: In these 200 years, how much progress has been made in business studies in Peru? We found bibliometric analysis to be the most appropriate method to answer this question. The software used to analyze the interrelationships between articles was Vosviewer, a software that allows the creation and visualization of bibliometric networks. Using the search terms "Peru" and "Business", we retrieved 908 articles from the Scopus Database

A Bibliometric Analysis on the state of the art of Neuromarketing research in Web of Science

Neuromarketing is an ever-evolving field and as such it is important to have an image on where we stand today regarding research about it. In order to study the state of the art of neuromarketing research in Web of Science, we carried out a bibliometric analysis with Vosviewer software. Using the keyword “neuromarketing” as the only search term, we retrieved 184 scientific articles from the Web of Science of Core Collection. We carried out all 5 possible types of analyses allowed on Vosviewer: co-authorship, co-occurrence, citation, bibliographic coupling, and co-citation. The results show that the United States is at the forefront of the field, having the most citations and published documents alongside being the most popular country for co-authored works, and also being the country most involved in citations. Most of the countries heavily involved in neuromarketing research are from Europe, with England being the most involved. Regarding the articles themselves, the most popular keywords are those related to research fields, other than neuromarketing, such as neuroscience, neuroeconomics, advertising, consumer decisions, among others. Likewise, the most popular journals for neuromarketing articles are those in the fields marketing, consumer behavior, psychology, neuroscience, etc. Other results show that the most popular cited journals are from the United States while the most popular cited authors are from Europe