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- 저자 : Arjona, Francisco M. (검색결과 9 건)
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An Improved SVPWM Control of Voltage Imbalance in Capacitors of a Single-Phase Multilevel Inverter
Ramirez, Fernando Arturo,Arjona, Marco A. The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.5
This paper presents a modified Space Vector Pulse Width Modulation Technique (SVPWM), which solves the well-known problem of voltage imbalance in the capacitors of a single-phase multilevel inverter. The proposed solution is based on the measurement of DC voltage levels at each capacitor of the inverter DC bus. The measurements are then used to adjust the size of the active vectors within the SVPWM algorithm to keep the voltage waveform sinusoidal regardless of any voltage imbalance on the DC link capacitors. When a voltage deviation exceeds a predetermined hysteresis band, the correspondent voltage vector is restricted to restore the voltage level to an acceptable threshold. Hence, the need for external voltage regulators for the voltage capacitors is eliminated. The functionality of the proposed algorithm is successfully demonstrated through simulations and experiments on a grid tied application.
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Ramirez, Fernando Arturo,Arjona, Marco A.,Hernandez, Concepcion The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.2
This paper presents a novel Parameter-Independent Fictive-Axis (PIFA) approach for the Voltage-Oriented Control (VOC) algorithm used in grid-tied single-phase inverters. VOC is based on the transformation of the single-phase grid current into the synchronous reference frame. As a result, an orthogonal current signal is needed. Traditionally, this signal has been obtained from fixed time delays, digital filters or a Hilbert transformation. Nevertheless, these solutions present stability and transient drawbacks. Recently, the Fictive Axis Emulation (FAE) VOC has emerged as an alternative for the generation of the quadrature current signal. FAE requires detailed information of the grid current filter along with its transfer function for signal creation. When the transfer function is not accurate, the direct and quadrature current components present steady-state oscillations as the fictive two-phase system becomes unbalanced. Moreover, the digital implementation of the transfer function imposes an additional computing burden on the VOC. The PIFA VOC presented in this paper, takes advantage of the reference current to create the required orthogonal current, which effectively eliminates the need for the filter transfer function. Moreover, the fictive signal amplitude and phase do not change with a frequency drift, which results in an increased reliability. This yields a fast, linear and stable system that can be installed without fine tuning. To demonstrate the good performance of the PIFA VOC, simulation and experimental results are presented.
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Fernando Arturo Ramirez,Marco A. Arjona,Concepcion Hernandez 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.2
This paper presents a novel Parameter-Independent Fictive-Axis (PIFA) approach for the Voltage-Oriented Control (VOC) algorithm used in grid-tied single-phase inverters. VOC is based on the transformation of the single-phase grid current into the synchronous reference frame. As a result, an orthogonal current signal is needed. Traditionally, this signal has been obtained from fixed time delays, digital filters or a Hilbert transformation. Nevertheless, these solutions present stability and transient drawbacks. Recently, the Fictive Axis Emulation (FAE) VOC has emerged as an alternative for the generation of the quadrature current signal. FAE requires detailed information of the grid current filter along with its transfer function for signal creation. When the transfer function is not accurate, the direct and quadrature current components present steady-state oscillations as the fictive two-phase system becomes unbalanced. Moreover, the digital implementation of the transfer function imposes an additional computing burden on the VOC. The PIFA VOC presented in this paper, takes advantage of the reference current to create the required orthogonal current, which effectively eliminates the need for the filter transfer function. Moreover, the fictive signal amplitude and phase do not change with a frequency drift, which results in an increased reliability. This yields a fast, linear and stable system that can be installed without fine tuning. To demonstrate the good performance of the PIFA VOC, simulation and experimental results are presented.
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An Improved SVPWM Control of Voltage Imbalance in Capacitors of a Single-Phase Multilevel Inverter
Fernando Arturo Ramirez,Marco A. Arjona 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.5
This paper presents a modified Space Vector Pulse Width Modulation Technique (SVPWM), which solves the well-known problem of voltage imbalance in the capacitors of a single-phase multilevel inverter. The proposed solution is based on the measurement of DC voltage levels at each capacitor of the inverter DC bus. The measurements are then used to adjust the size of the active vectors within the SVPWM algorithm to keep the voltage waveform sinusoidal regardless of any voltage imbalance on the DC link capacitors. When a voltage deviation exceeds a predetermined hysteresis band, the correspondent voltage vector is restricted to restore the voltage level to an acceptable threshold. Hence, the need for external voltage regulators for the voltage capacitors is eliminated. The functionality of the proposed algorithm is successfully demonstrated through simulations and experiments on a grid tied application.
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Iron oxide coating films in soda-lime glass by triboadhesion
J. O. Aguilar,J. M. Rodríguez-Lelis,M. J. Arjona 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.4
In the triboadhesion process the coating material is passed through a rotating cotton mop and the substrate to be coated. The cotton mop rotates at high velocity and exerts pressure on the surface of the substrate. The combined effect of pressure and velocity of the coating mop on the substrate increases its temperature close to the melting point, allowing deposition and diffusion of the coating material within the substrate. After it is deposited, its particles are embedded within the base material forming a thin film composite. The amount of the coating material deposited on the substrate has its maximum at the surface and then decreases as a function of the local temperature within the base material. Bearing this in mind, in the present work, triboadhesion is employed to deposit iron oxide in a substrate of soda-lime glass, with the purpose of determining the feasibility of using this technique for solar control coatings. It was found, through electronic scan microscopy, that a composite material film is formed following the coating direction. Reflectance and transmittance tests were carried out on the glass samples. A 20% difference was found in the visible spectral region (VIS), and a reduction between 10 and 20% in the Near Infrared Region (NIR). These results showed that the triboadhesion is a promising technique for the application of thin films for solar control or solar cells.
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Areli Burgueño‑Roman,Gloria M. Castañeda‑Ruelas,Ramón Pacheco‑Arjona,Maribel Jimenez‑Edeza 한국유전학회 2019 Genes & Genomics Vol.41 No.7
Background River water has been implicated as a source of non-typhoidal Salmonella (NTS) serovars in Mexico. Objective To dissect the molecular pathogenesis and defense strategies of seven NTS strains isolated from river water in Mexico. Methods The genome of Salmonella serovars Give, Pomona, Kedougou, Stanley, Oranienburg, Sandiego, and Muenchen were sequenced using the whole-genome shotgun methodology in the Illumina Miseq platform. The genoma annotation and evolutionary analyses were conducted in the RAST and FigTree servers, respectively. The MLST was performed using the SRST2 tool and the comparisons between strains were clustered and visualized using the Gview server. Experimental virulence assay was included to evaluate the pathogenic potential of strains. Results We report seven high-quality draft genomes, ranging from ~ 4.61 to ~ 5.12 Mb, with a median G + C value, coding DNA sequence, and protein values of 52.1%, 4697 bp, and 4,589 bp, respectively. The NTS serovars presented with an open pan-genome, offering novel genetic content. Each NTS serovar had an indistinguishable virulotype with a core genome (352 virulence genes) closely associated with Salmonella pathogenicity; 13 genes were characterized as serotype specific, which could explain differences in pathogenicity. All strains maintained highly conserved genetic content regarding the Salmonella pathogenicity islands (1–5) (86.9–100%), fimbriae (84.6%), and hypermutation (100%) genes. Adherence and invasion capacity were confirmed among NTS strains in Caco-2 cells. Conclusion Our results demonstrated the arsenal of virulence and defense molecular factors harbored on NTS serovars and highlight that environmental NTS strains are waterborne pathogens worthy of attention.
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Upstream kinases of plant Sn RK s are involved in salt stress tolerance
Barajas‐,Lopez, Juan de Dios,Moreno, Jose Ramon,Gamez‐,Arjona, Francisco M.,Pardo, Jose M.,Punkkinen, Matleena,Zhu, Jian‐,Kang,Quintero, Francisco J.,Fujii, Hiroaki John Wiley and Sons Inc. 2018 The Plant journal Vol.93 No.1
<▼1><P><B>Summary</B></P><P>Sucrose non‐fermenting 1‐related protein kinases (SnRKs) are important for plant growth and stress responses. This family has three clades: SnRK1, SnRK2 and SnRK3. Although plant SnRKs are thought to be activated by upstream kinases, the overall mechanism remains obscure. Geminivirus Rep‐Interacting Kinase (GRIK)1 and GRIK2 phosphorylate SnRK1s, which are involved in sugar/energy sensing, and the <I>grik1‐1 grik2‐1</I> double mutant shows growth retardation under regular growth conditions. In this study, we established another Arabidopsis mutant line harbouring a different allele of gene <I>GRIK1</I> (<I>grik1‐2 grik2‐1</I>) that grows similarly to the wild‐type, enabling us to evaluate the function of GRIKs under stress conditions. In the <I>grik1‐2 grik2‐1</I> double mutant, phosphorylation of SnRK1.1 was reduced, but not eliminated, suggesting that the <I>grik1‐2</I> mutation is a weak allele. In addition to high sensitivity to glucose, the <I>grik1‐2 grik2‐1</I> mutant was sensitive to high salt, indicating that GRIKs are also involved in salinity signalling pathways. Salt Overly Sensitive (SOS)2, a member of the SnRK3 subfamily, is a critical mediator of the response to salinity. GRIK1 phosphorylated SOS2 <I>in vitro</I>, resulting in elevated kinase activity of SOS2. The salt tolerance of <I>sos2</I> was restored to normal levels by wild‐type SOS2, but not by a mutated form of SOS2 lacking the T168 residue phosphorylated by GRIK1. Activation of SOS2 by GRIK1 was also demonstrated in a reconstituted system in yeast. Our results indicate that GRIKs phosphorylate and activate SnRK1 and other members of the SnRK3 family, and that they play important roles in multiple signalling pathways <I>in vivo</I>.</P></▼1><▼2><P><B>Significance Statement</B></P><P>Since plants face diverse, often coincidental stresses throughout their lifetime, they have to integrate multiple signals to organize growth, development and stress responses. This work shows that GRIKs, which are essential players in sugar signalling pathway as upstream kinases of SnRK1s, also work in salt tolerance of Arabidopsis and identified SOS2, a SnRK3, as a potential substrate of GRIKs in the salinity signalling pathway.</P></▼2>
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"Beach Lifeguards' Sun Exposure and Sun Protection in Spain"
de Troya Martin, Magdalena,Sanchez, Nuria Blazquez,Garcia Harana, Cristina,Leiva, Ma Carmen Alarcon,Arjona, Jose Aguilera,Ruiz, Francisco Rivas,de Galvez Aranda, Ma Victoria Occupational Safety and Health Research Institute 2021 Safety and health at work Vol.12 No.2
Background: Sunburn is the main avoidable cause of skin cancer. Beach lifeguards spend many hours exposed to the effects of solar radiation during their work day, precisely at times of the year when levels of solar irradiation are highest. The aim of this study is to quantify the risk to beach lifeguards of sun exposure. Methods: A descriptive cross-sectional study was carried out in the Western Costa del Sol, southern Spain, during the summer of 2018. The research subjects were recruited during a skin cancer prevention course for beach lifeguards. All participants were invited to complete a questionnaire on their habits, attitudes, and knowledge related to sun exposure. In addition, ten were specially monitored using personal dosimeters for three consecutive days, and the results were recorded in a photoprotection diary. A descriptive analysis (mean and standard deviation for the quantitative variables) was performed, and inter-group differences were evaluated using the Mann-Whitney U test. Results: Two hundred fifteen lifeguards completed the questionnaire, and 109 met the criteria for inclusion in this analysis. The mean age was 23.8 years (SD: 5.1), 78.0% were male, 71.5% were phototype III or IV (Fitzpatrick's phototype), and 77.1% had experienced at least one painful sunburn during the previous summer. The mean daily personal ultraviolet exposure per day, the minimal erythema dose, and the standard erythema dose, in J/m<sup>2</sup>, were 634.7 [standard deviation (SD): 356.2], 2.5 (SD: 1.4) and 6.35 (SD: 3.6), respectively. Conclusion: Beach lifeguards receive very high doses of solar radiation during the work day and experience correspondingly high rates of sunburn. Intervention strategies to modify their sun exposure behavior and working environment are necessary to reduce the risk of skin cancer for these workers and to promote early diagnosis of the disease.
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