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Fuzzy Logic Based MPPT Controller for a PV System
The output power of a photovoltaic (PV) module depends on the solar irradiance and the operating temperature; therefore, it is necessary to implement maximum power point tracking controllers (MPPT) to obtain the maximum power of a PV system regardless of variations in climatic conditions. The traditional solution for MPPT controllers is the perturbation and observation (P&O) algorithm, which presents oscillation problems around the operating point; the reason why improving the results obtained with this algorithm has become an important goal to reach for researchers. This paper presents the design and modeling of a fuzzy controller for tracking the maximum power point of a PV System. Matlab/Simulink (MathWorks, Natick, MA, USA) was used for the modeling of the components of a 65 W PV system: PV module, buck converter and fuzzy controller; highlighting as main novelty the use of a mathematical model for the PV module, which, unlike diode based models, only needs to calculate the curve fitting parameter. A P&O controller to compare the results obtained with the fuzzy control was designed. The simulation results demonstrated the superiority of the fuzzy controller in terms of settling time, power loss and oscillations at the operating point.
Journal Article
Faddeev–Jackiw Hamiltonian formulation for general exotic bi-gravity
General exotic bi-gravity, obtained in Ozkan et al. (Phys Rev Lett 123(3):031303, 2019), is a unitary parity-preserving model which describes two interacting spin-two fields in three-dimensional spacetime. Adopting a symplectic viewpoint, we investigate the dynamical structure of general exotic bi-gravity theory. In particular, by exploiting the properties of the corresponding pre-symplectic matrix and its associated zero-modes, we explicitly derive all constraints of the theory, including the integrability conditions and scalar relationships between all the parameters and fields defining the model. Then, as an application, these scalar relationships are used for studying the anti-de Sitter background. After that, we derive the gauge transformations for the dynamical variables from the structure of the remaining zero-modes, meaning that such zero-modes are indeed the generators of the gauge symmetry of the theory. Finally, by switching off one of the four coupling constants
β
n
and assuming the invertibility of some of the dreibeins, we find that the general exotic bi-gravity theory has two physical degrees of freedom.
Journal Article
Canonical description of exotic general massive gravity
Exotic General Massive Gravity is the next-to-simplest gravitational theory fulfilling the so-called third-way consistency, the simplest being Minimal Massive Gravity. We investigate the canonical structure of the first-order formulation of Exotic General Massive Gravity. By using the Dirac Hamiltonian formalism, we systematically discover the complete set of physical constraints, including primary, secondary, and tertiary ones, and explicitly compute the Poisson bracket algebra between them. In particular, we demonstrate that the consistency condition for the tertiary constraints provides explicit expressions which can be solved algebraically for the auxiliary fields f and h in terms of the dreibein e. In this configuration, to confirm that the theory is ghost-free, the whole set of constraints is classified into first and second-class ones showing the existence of only two physical degrees of freedom corresponding to one massive graviton. Furthermore, we identify the transformation laws for all of the dynamical variables corresponding essentially to gauge symmetries, generated by the first-class constraints. Finally, by taking into account all the second-class constraints, we explicitly compute the Dirac matrix together with the Dirac’s brackets.
Journal Article
Symplectic realization of two interacting spin-two fields in three dimensions
A
bstract
We constructed a symplectic realization of the dynamic structure of two interacting spin-two fields in three dimensions. A significant simplification refers to the treatment of constraints: instead of performing a Hamiltonian analysis
à la
Dirac, we worked out a method that only uses properties of the pre-symplectic two-form matrix and its corresponding zero-modes to investigate the nature of constraints and the gauge structure of the theory. For instance, we demonstrate that the contraction of the zero-modes with the potential gradient, yields explicit expressions for the whole set of constraints on the dynamics of the theory, including the symmetrization condition and an explicit relationship between the coupling and cosmological constants. This way, we further identify the necessary conditions for the existence of a unique non-linear candidate for a partially massless theory, using only the expression for the interaction parameters of the model. In the case of gauge structure, the transformation laws for the entire set of dynamical variables are more straightforwardly derived from the structure of the remaining zero-modes; in this sense, the zero-modes must be viewed as the generators of the corresponding gauge transformations. Thereafter, we use an appropriate gauge-fixing procedure, the time gauge, to compute both the quantization brackets and the functional measure on the path integral associated with our model. Finally, we confirm that three-dimensional bi-gravity has two physical degrees of freedom per space point. With the above, we provide a new perspective for a better understanding of the dynamical structure of theories of interacting spin-two fields, which does not require the constraints to be catalogued as first- and second-class ones as in the case of Dirac’s standard method.
Journal Article
Artificial Neural Networks in MPPT Algorithms for Optimization of Photovoltaic Power Systems: A Review
The use of photovoltaic systems for clean electrical energy has increased. However, due to their low efficiency, researchers have looked for ways to increase their effectiveness and improve their efficiency. The Maximum Power Point Tracking (MPPT) inverters allow us to maximize the extraction of as much energy as possible from PV panels, and they require algorithms to extract the Maximum Power Point (MPP). Several intelligent algorithms show acceptable performance; however, few consider using Artificial Neural Networks (ANN). These have the advantage of giving a fast and accurate tracking of the MPP. The controller effectiveness depends on the algorithm used in the hidden layer and how well the neural network has been trained. Articles over the last six years were studied. A review of different papers, reports, and other documents using ANN for MPPT control is presented. The algorithms are based on ANN or in a hybrid combination with FL or a metaheuristic algorithm. ANN MPPT algorithms deliver an average performance of 98% in uniform conditions, exhibit a faster convergence speed, and have fewer oscillations around the MPP, according to this research.
Journal Article
Metaheuristic Parameter Identification of Motors Using Dynamic Response Relations
This article presents the use of the equations of the dynamic response to a step input in metaheuristic algorithm for the parametric estimation of a motor model. The model equations are analyzed, and the relations in steady-state and transient-state are used as delimiters in the search. These relations reduce the number of random parameters in algorithm search and reduce the iterations to find an acceptable result. The tests were implemented in two motors of known parameters to estimate the performance of the modifications in the algorithms. Tests were carried out with three algorithms (Gray Wolf Optimizer, Jaya Algorithm, and Cuckoo Search Algorithm) to prove that the benefits can be extended to various metaheuristics. The search parameters were also varied, and tests were developed with different iterations and populations. The results show an improvement for all the algorithms used, achieving the same error as the original method but with 10 to 50% fewer iterations.
Journal Article
Impact of universal immunization program with monoclonal antibody nirsevimab on reducing the burden of serious bronchiolitis that need pediatric intensive care
RSV bronchiolitis remains the leading cause of hospitalization in children under 1 year of age. It is estimated that 2–6% of cases will be hospitalized on pediatric intensive care units (PICUs). In October 2023, a universal immunization program with the monoclonal antibody nirsevimab was implemented in Catalonia. The aim of the study was to analyze the impact of the nirsevimab immunization on the burden of bronchiolitis admitted to a PICU and resulting changes in epidemiological, clinical, and microbiological characteristics comparing the pre-nirsevimab (pre-N) with the post-nirsevimab (post-N) period. This was a prospective, descriptive, and observational study. Patients with severe bronchiolitis admitted to reference children’s hospital PICU, between September 2010 and February 2024 were included. Demographic and clinical data were collected and viral laboratory etiological diagnosis was carried out. 1531 patients were recruited, 1458 in the pre-N seasons and 73 after its introduction (58% males, median age 52 days), of which 67% were immunized with nirsevimab. The total number of PICU bronchiolitis admissions, the ratio, and the RSV etiology were significantly lower in the post-N period (
p
= 0.03,
p
< 0.001, and
p
= 0.039, respectively). Significant higher age at admission (
p
< 0.001) and lower hospital length of stay (
p
< 0.001) was observed comparing pre-N vs. post-N period.
Conclusion
: Nirsevimab appears to have an important impact on reducing the number and length of stay of PICU admissions due to RSV bronchiolitis.
What Is Known:
• Bronchiolitis is the most common viral infection of the lower respiratory tract in infants.
• It represents 13% of the total pediatric intensive care admissions, typically during winter. This is one of the causes that produces a collapse in the health care systems all around the world.
What Is New:
• In October 2023, universal immunization with monoclonal antibody nirsevimab of all children under 6 months of age was started in the majority of autonomous communities in Spain.
• Recent publications from the nirsevimab clinical trials have evidenced a high RSV protective effect, but data on its effect on real life patients who require pediatric intensive care unit admission are missing.
Journal Article
The American De coelo: Heaven and Earth in the New World’s First Printed Work on Natural Philosophy
The article analyses Alonso de la Vera Cruz’s ideas on cosmography, including both celestial and geographical conceptions, displayed in De coelo from his Physica speculatio (1557). This book introduced in New Spain the hegemonic natural knowledge of the time as well as alternative ideas. At the same time, living for years in the New World, de la Vera Cruz drew on his own experience when discussing the qualities of the Americas and their inhabitants. Unlike the imperial cosmography of the time, he valued not only the natural qualities of those lands but also their inhabitants, which had important social implications. We argue that De la Vera Cruz reinterpreted European notions to adapt them to the Americas and, at the same time, developed a local perspective that transferred the idea of centrality from Europe to the New World. In doing so, he had to mediate with both local and transatlantic interests and visions. Reissued three more times in Salamanca since the 1569 edition, the Physica speculatio included references to the coasts of the American continent, which constitutes an exception to the secret nature of this kind of cosmographical information in the Ibero-American world.
Journal Article
Lesson study in science teacher preparation programs: a literature review
PurposeThis article aims to identify and describe the research outcomes of studies that have employed the theoretical framework of lesson study (LS) in initial science teacher preparation programs. The focus is on the impact of LS on preservice teachers’ (PST) pedagogical and content knowledge, beliefs, routines and norms for professional learning and instructional practices.Design/methodology/approachA systematic approach was employed to compile pertinent literature by initially searching scholarly databases using specific keywords and phrases related to prospective science teacher preparation. Seventeen studies, encompassing both qualitative research and mixed-methods research, met the inclusion criteria and significantly contributed to the study’s findings. The authors independently conducted a coding process, applying a predefined code scheme based on Lewis et al.'s (2019) theoretical framework. The outcomes of the coding process were compared, and reliability tests were conducted to ensure the consistency of the coding.FindingsIn preservice science teacher (PSST) education, LS proves transformative, enriching pedagogical and content knowledge, shaping beliefs, fostering collaboration and influencing instructional practices. Its collaborative, reflective and iterative nature significantly contributes to the professional growth of preservice science teachers, preparing them for effective, student-centered teaching practices. Further investigation is warranted in the realm of LS, particularly concerning preservice science teachers and their beliefs.Originality/valueThis literature review on science PSTs is one of the pioneering efforts to employ the professional development framework crafted by Lewis et al. (2019).
Journal Article