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Isolated single-stage DABSR DC/AC converter with series-power decoupling to interface PV with the single-phase grid
No full textThis article presents an isolated single-stage Dual-Active-Bridge Series-Resonant (DABSR) DC-AC converter with series-power decoupling (SPD) to interface PV with the single-phase grid. A third port is added in the proposed DABSR DC-AC converter, which is series-connected on the AC side to power decoupling. Therefore, the electrolytic capacitors, typically used on the DC side, are replaced by film capacitors. The single-phase time-variant power is decoupled by controlling the time-variant voltage on the third port, which depends on the power amplitude, the filter capacitor and the grid frequency. A novel modulation is proposed where the grid and the third port voltages are modulated by unipolar PWM while the PV voltage is modulated by duty ratio. The power flow is controlled by phase-shift modulation. High efficiency is obtained due to soft-switching operation into all active bridges. Besides, low THD in the grid current is obtained. MPPT is performed with high accuracy. Finally, the proposed converter is compared with a similar DABSR DC-AC converter without SPD (WoSPD). The novel modulation, converter design and the control strategy are presented and validated by simulation. © 2021 IEEE.This work was financed by CONCYTEC-FONDECYT within the call for projects E041-01 [Contract Number 096-2018
Life-cycle cost analysis for an incremental seismic rehabilitation project
No full textThe author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This project was partially funded by CONCYTEC within the framework of the 027-2015-FONDECYT Agreement.Incremental seismic rehabilitation (ISR) consists of a set of discrete rehabilitation actions in order to decrease initial costs and to avoid long-lasting disruptions. Nevertheless, there are few cases of incrementally retrofitted buildings and few studies about its economic feasibility. The objective of this work is to evaluate the differences between incremental and single-stage rehabilitation in terms of economic losses during the building’s life span. For this purpose, this work analyzes three rehabilitation proposals to improve seismic performance of typical school buildings. Based on P58 FEMA (Federal Emergency Management Agency) methodology, expected repair costs and benefits were calculated for each rehabilitation intervention. Results confirm the potential of ISR for improving essential buildings.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy
Paralytic shellfish toxins in Peruvian scallops associated with blooms of Alexandrium ostenfeldii (Paulsen) Balech & Tangen in Paracas Bay, Peru
No full textT. Cuellar-Martinez acknowledges the financial support of the Project Concytec - World Bank ?Characterization and forecast of extreme events in the Peruvian sea using an operational system of oceanic information? (05-2019-FONDECYT-BM), through its executing unit Fondo Nacional de Desarrollo Cient?fico, Tecnol?gico y de Innovaci?n Tecnol?gica (Fondecyt). This work is a contribution to the cooperative agreement between the Instituto del Mar del Per? (IMARPE) and the Institut de Recherche pour le Developpement (IRD) through the IRD international network GDRI DEXICOTROP and the JEAI DYSRUP. The authors thank to: L. Ycochea for toxin data, A. Lorenzo Puitiza for data from IMARPE-PISCO laboratory, A. E. Franco Garc?a for the environmental data.In recent years, dense Alexandrium ostenfeldii blooms have been reported in different coastal areas. In this study, we report for the first time the occurrence of A. ostenfeldii blooms associated with the detection of paralytic shellfish toxins (PSTs) in the Peruvian scallop (Argopecten purpuratus) from Paracas Bay. Alexandrium ostenfeldii blooms occurred at the end of summer and early fall, after the increase of riverine input and under stratified conditions following a decrease in wind velocity. The highest abundances occurred during warm sea surface temperatures (18–27 °C). High PST concentrations that exceed the maximum permissible level (800 ?g STX eq. kg?1) occurred even under low A. ostenfeldii abundances (20 × 103 cells l?1). Our results contribute to a better understanding of the dynamics of A. ostenfeldii in coastal systems influenced by riverine inputs and upwelling and can be used to improve monitoring programs and allow the implementation of mitigation measures along the Peruvian coast. © 2021 Elsevier LtdConsejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Strain and grain size determination of ceo2 and tio2 nanoparticles: Comparing integral breadth methods versus rietveld, µ-raman, and tem
No full textFunding: The authors thank the Fondo Nacional de Desarrollo Científico, Tecnológico y de Inno-vación Tecnológica (PROCIENCIA-CONCYTEC), project number: 177-2020-FONDECYT (PROCIEN-CIA), project CLEAN NANOMAGNETIC. “The APC was funded by PROCIENCIA”.Various crystallite size estimation methods were used to analyze X-ray diffractograms of spherical cerium dioxide and titanium dioxide anatase nanoparticles aiming to evaluate their reliability and limitations. The microstructural parameters were estimated from several integral breadth methods such as Scherrer, Monshi, Williamson–Hall, and their variants: (i) uniform deformation model, (ii) uniform strain deformation model, and (iii) uniform deformation energy density model. We also employed the size–strain plot and Halder–Wagner method. For this purpose, an instrumental resolution function of an Al2O3 standard was used to subtract the instrumental broadening to estimate the crystallite sizes and strain, and the linear regression analysis was used to compare all the models based on the coefficient of determination. The Rietveld whole powder pattern decomposition method was introduced for comparison purposes, being the best candidate to fit the X-ray diffraction data of metal-oxide nanoparticles. Refined microstructural parameters were obtained using the anisotropic spherical harmonic size approach and correlated with the above estimation methods and transmission electron microscopy images. In addition, µ-Raman spectra were recorded for each material, estimating the mean crystallite size for comparison by means of a phonon confinement model. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Sustainable synthesis, reduction and applications of graphene obtained from renewable resources
No full textThis research was funded by FONDECYT-CONCYTEC , grant number 063-2018-FONDECYT-BM .Graphene is a revolutionary material with outstanding electrical, mechanical, thermal, and structural properties. The synthesis of graphene and its derivatives generally requires expensive and poisonous reagents. However, contemporary research efforts are switching towards more sustainable routes. The present review focused on the synthesis, performance, and applications of graphene-derived nanomaterials synthesized from waste biomass and reduced by green alternatives. Graphitization of waste carbon precursors is the most used method to obtain high purity graphite alternatives. Other methods, such as CVD, hydrothermal, laser, and CAS, have been investigated. Graphene yielded from biomass precursors exhibits properties similar to those from conventional sources. Green reduction of graphene oxide is carried out mostly by plant extracts from fruits, leaves, and other parts, which contain a high concentration of phenolic compounds. The as-prepared bio-waste and green-reduced graphene alternatives were applied in wastewater treatment, electrochemical storage devices, and metal ion sensors. In some cases, graphene showed significantly better performance than previous carbon-based nanomaterials reported in the literature. Despite being in its early stages of development, green-synthesized graphene has demonstrated great potential. As the interest in the development of sustainable alternatives continues to grow, future graphene research is expected to aim for this new line of research. © 2021Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Three dimensional numerical solution for the bending study of magneto-piezo-elastic spherical and cylindrical shells
No full textThis paper was written in the context of the project: “Desarrollo de materiales avanzados para el diseño de nuevos productos y servicios tecnológicos para la minería Peruana” founded by CONCYTEC (FONDECYT and GRUPO BANCO MUNDIAL) under the contract number N° 032-2019-FONDECYT-BM-INC.INV. The authors of this manuscript appreciate the financial support from the Peruvian Government.This paper presents an exact solution for the static analysis of magneto-electro-elastic simply supported shallow shells panels. The mechanical equations are derived via equilibrium elasticity relations. The electrical and magnetic governing equations are obtained by electrostatic and magnetostatic equilibrium relations. The shell displacements, electrical and magnetic potential functions are solved analytically by the Navier closed form solutions. The governing equations formulated in terms of thickness coordinate are solved semi-analytically by using the differential quadrature method. The Lagrange polynomials are employed as basis functions. The equations are discretized per each layer by the Chebyshev-Gauss-Lobatto grid distribution. The continuity conditions in the adjacent layers for mechanical displacement, transverse dielectric displacement, electric and magnetic scalar function and transverse magnetic induction are complied. The correct load traction condition is considered at the top and bottom of the shell. Numerical results for spherical, cylindrical and rectangular panels are reported. The results are in excellent agreement with other 3D elasticity solutions reported in the literature so a new benchmark problem for shell is proposed. © 2021 Elsevier LtdConsejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Ultrasound processing of fruits and vegetables, structural modification and impact on nutrient and bioactive compounds: a review
No full textThe authors are grateful to the S?o Paulo Research foundation (FAPESP, Brazil) for funding the project n? 2019/05043-6 and the ME Caetano-Silva post-doctoral fellowship (2017/16977-4), the National Council for Scientific and Technological Development (CNPq, Brazil) for the PED Augusto productivity grant (306557/2017-7, 310839/2020-3), the Fondo Nacional de Desarrollo Cient?fico, Tecnol?gico y de Innovaci?n Tecnol?gica (FONDECYT, Peru) from the ?Consejo Nacional de Ciencia, Tecnolog?a e Innovaci?n Tecnol?gica? (CONCYTEC, Peru) for funding the project n? 409-2019-FONDECYT, and to the Universidad Privada del Norte (UPN, Peru) for funding the project n? 20201005.This review presents an updated analysis regarding the application of ultrasound technology in fruits, vegetables and their derivatives. The relationship among structure, processing, the quantity and quality of nutrients and bioactive compounds are discussed. Initially, we discussed the effect of ultrasound processing on the structure of the matrices at tissues, cells and molecules levels, also considering the different factors that influence the reported responses. Subsequently, the effect on nutrients and bioactive compound quantity (concentration) and quality (bioaccessibility ? bioavailability ? bioactivity) is evaluated. Ultrasound processing resulting in tissues and cell disruption, fibre breakage, isomerisation, micellisation, among other modifications, improving the extractability of compounds and/or resulting in their degradation. Moreover, the obtained new matrix interacts differently with the human body, affecting the compound accessibility, which can be increased. In conclusion, different possibilities are discussed regarding using ultrasound processing to enhance healthy aspects of plant-based food products. © 2021 Institute of Food Science and TechnologyConsejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Use of SARS-CoV-2 genomes to estimate the effective reproductive number (RT) in Peru during march – april 2020 [Uso de genomas de SARS-CoV-2 para la estimación del número reproductivo efectivo (RT) en Perú durante marzo y abril del 2020]
No full textEste trabajo fue financiado por el Fondo Nacional de Desarrollo Cient?fico y Tecnol?gico y de Innovaci?n Tecnol?gica (Fondecyt-Per?) en el marco del ?Proyecto de Mejoramiento y Ampliaci?n de los Servicios del Sistema Nacional de Ciencia, Tecnolog?a e Innovaci?n Tecnol?gica? [N?mero de contrato 34?2019-FONDECYT-BM-INC. INV.], y por el CONCYTEC-FONDECYT en el marco del concurso ?Proyectos Especiales: Respuesta al COVID-19 2020-01? [n?mero de contrato 046-2020-FONDECYT].The understanding of COVID-19, caused by the SARS-CoV-2, is essential to improve evidence-based public health policies. The effective reproductive number (Rt) in Peru was estimated using information from 113 complete genomes sequenced by the Instituto Nacional de Salud del Perú (INS), available in the GISAID public database. The Rt trend during March and April of 2020 was found to be similar to results from other epidemiological reports. The Rt decreased during the first two weeks of March. Its lowest value was reported during the week after the quarantine began. The Rt increased moderately after the second week of April. The implication of early decisions taken to mitigate the transmission are discussed. Genomic surveillance will be necessary to understand the transmission and evolution of SARS-CoV-2 in Peru, and will complement the epidemiological information. © 2021, Instituto Nacional de Salud. All rights reserved.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Variabilidad espacio temporal de la calidad del agua del rio Cunas evaluada mediante indicadores ambientales, Chupaca
No full textLa gestión de cuencas hidrográficas requiere de información que permita intervenir posibles fuentes que afectan los sistemas acuáticos. Se evaluó la calidad del agua superficial en la cuenca del río Cunas (Perú) mediante métodos estadísticos multivariado e índice de calidad de agua ICA-PE. Se establecieron 27 sitios de muestreo en el río Cunas y nueve sitios en el río tributario. Las muestras de agua se colectaron en dos épocas climáticas contrastantes y la determinación del ICA-PE se realizó en base a parámetros fisicoquímicos y bacteriológico.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy
Application of Multivariate Statistical Methods and Water Quality Index for the Evaluation of Surface Water Quality in the Cunas River Basin, Peru
No full textWatershed management requires information that allows the intervention of possible sources that affect aquatic systems. Surface water quality in the Cunas river basin (Peru) was evaluated using multivariate statistical methods and the CCME-WQI water quality index. Twenty-seven sampling sites were established in the Cunas River and nine sites in the tributary river. Water samples were collected in two contrasting climatic seasons and the CCME-WQI was determined based on physicochemical and bacteriological parameters.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte