806 research outputs found

    Statistical optimization of α-amylase production by Escherichia coliusing extruded bean as nitrogen and carbon source

    Full text link
    Response surface methodology based on mixture design was employed for statistical optimization of medium components for the growth and production of α-amylase by Escherichia coli pAC92. The combined effects of media constituents (peptone, yeast extract and extruded beans) were analyzed using a cubic model, which was developed by3-factor simplex lattice mixture design in predicting the optimum yield of growth and α-amylase activity. Results evidenced that extruded common bean was more effective as a nutrient source for E.colipAC92 growth. On the other hand, the completely substituted medium with extruded common bean resulted in 68% of increase in the growth of Escherichia coli pAC92. In addition, the culture medium containing 0.5% of extruded bean and 0.5% of peptone reached a α-amylase activity of 44.59 U. The optimal medium composition was determined by a numerical method based on desirability function, by which the optimal composition for maximum optical density and enzyme activity was found using 0.5% peptone and 0.5% extruded common bean as media constituents. Therefore, these results evidenced that extruded common bean can be successfully used as substitute of peptone and yeast extract in culture media for production of α-amylase byE.colipAC92

    Efficiency comparison of different DC-DC converter architectures for a power supply of a LiDAR system

    Get PDF
    LiDAR (Light Detection And Ranging) is a technology used to meas-ure distances to objects. Internally, a LiDAR system is constituted by several components, including a power supply, which is responsible to provide the dis-tinct voltage levels necessary for all the components. In this context, this paper presents an efficiency comparison of three different DC-DC converter architec-tures for a LiDAR system, each one composed of three DC-DC converters: in parallel; in cascade; and hybrid (mix of parallel and cascade). The topology of the adopted integrated DC-DC converters is the synchronous buck Switched-Mode Power Supply (SMPS), which is a modified version of the basic buck SMPS topology. Three distinct SMPSs were considered: LM5146-Q1, LM5116, and TPS548A20RVER. These SMPSs were selected according to the require-ments of voltage levels, namely, 12 V, 5 V, and 3.3 V. Along the paper, the prin-ciple of operation of the SMPSs is presented, as well as the evaluation results obtained for different operating powers, allowing to establish a comprehensive efficiency comparison.This work has been supported by national funds through FCT—Fundação para a Ciência e Tecnologia within the Project Scope: UIDB/00319/2020, and also European Structural and Investment Funds in the FEDER component, through the Operational Competitiveness and Internationalization Programme (COMPETE 2020) [Project nº 037902; Funding Reference: POCI-01-0247-FEDER-037902]

    Wireless communication and management system for E-Bike dynamic inductive power transfer lanes

    Get PDF
    This paper presents the design, implementation, and testing of a wireless communication system for automatic identification of e-bikes and management of their battery charging in the context of dynamic inductive wireless power transfer (DIWPT) lanes. The proposed system checks if an e-bike, uniquely identified by its RFID tag, is authorized to receive energy from the lane coils and acts accordingly. An authentication mechanism was developed based on the use of embedded Wi-Fi boards attached to the coils and communicating with a central HTTP server with a MySQL database. The developed management system also provides other features, such as the recording of the number of lane coils used by each e-bike for billing purposes. The results from experimental tests on a laboratory prototype were used to validate the developed functionalities and assess the quality of service provided by the proposed system.This work was supported by FCT national funds, under the national support to R&D units grant,through the reference project UIDB/04436/2020 and UIDP/04436/2020

    Vehicle electrification: technologies, challenges and a global perspective for smart grids

    Get PDF
    Nowadays, due to economic and climate concerns, the private transportation sector is shifting for the vehicle electrification, mainly supported by electric and hybrid plug-in vehicles. For this new reality, new challenges about operation modes are emerging, demanding a cooperative and dynamic operation with the electrical power grid, guaranteeing a stable integration without omitting the power quality for the grid-side and for the vehicle-side. Besides the operation modes, new attractive and complementary technologies are offered by the vehicle electrification in the context of smart grids, which are valid for both on-board and off-board systems. In this perspective, this book chapter presents a global perspective and deals with challenges for the vehicle electrification, covering the key technologies toward a sustainable future. Among others, the flowing topics are covered: (1) Overview of power electronics structures for battery charging systems, including on-board and off-board systems; (2) State-of-the-art of communication technologies for application in the context of vehicular electrification, smart grids and smart homes; (3) Challenges and opportunities concerning wireless power transfer with bidirectional interface to the electrical grid; (4) Future perspectives about bidirectional power transfer between electric vehicles (vehicle-to-vehicle operation mode); (5) Unified technologies, allowing to combine functionalities of a bidirectional interface with the electrical grid and motor driver based on a single system; and (6) Smart grids and smart homes scenarios and accessible opportunities about operation modes.Fundação para a Ciência e Tecnologia (FCT

    Raising the Parallel Abstraction Level for Streaming Analytics Applications

    Get PDF
    In the stream processing domain, applications are represented by graphs of operators arbitrarily connected and filled with their business logic code. The APIs of existing Stream Processing Systems (SPSs) ease the development of transformations that recur in the streaming practice (e.g., filtering, aggregation and joins). In contrast, their parallelism abstractions are quite limited since they provide support to stateless operators only, or when the state is organized in a set of key-value pairs. This paper presents how the parallel patterns methodology can be revisited for sliding-window streaming analytics. Our vision fosters a design process of the application as composition and nesting of ready-to-use patterns provided through a C++17 fluent interface. Our prototype implements the run-time system of the patterns in the FastFlow parallel library expressing thread-based parallelism. The experimental analysis shows interesting outcomes. First, our pattern-based approach allows easy prototyping of different versions of the application, and the programmer can leverage nesting of patterns to increase performance (up to 37% in one of the two considered test-bed cases). Second, our FastFlow implementation outperforms (three times faster) the handmade porting of our patterns in popular JVM-based SPSs. Finally, in the concluding part of this paper, we explore the use of a task-based run-time system, by deriving interesting insights into how to make our patterns library suitable for multi backends

    A review on power electronics technologies for electric mobility

    Get PDF
    Concerns about greenhouse gas emissions are a key topic addressed by modern societies worldwide. As a contribution to mitigate such effects caused by the transportation sector, the full adoption of electric mobility is increasingly being seen as the main alternative to conventional internal combustion engine (ICE) vehicles, which is supported by positive industry indicators, despite some identified hurdles. For such objective, power electronics technologies play an essential role and can be contextualized in different purposes to support the full adoption of electric mobility, including on-board and off-board battery charging systems, inductive wireless charging systems, unified traction and charging systems, new topologies with innovative operation modes for supporting the electrical power grid, and innovative solutions for electrified railways. Embracing all of these aspects, this paper presents a review on power electronics technologies for electric mobility where some of the main technologies and power electronics topologies are presented and explained. In order to address a broad scope of technologies, this paper covers road vehicles, lightweight vehicles and railway vehicles, among other electric vehicles.This work has been supported by FCT – Fundação para a Ciência e Tecnologia with-in the Project Scope: UID/CEC/00319/2020. This work has been supported by the FCT Project DAIPESEV PTDC/EEI-EEE/30382/2017, and by the FCT Project new ERA4GRIDs PTDC/EEI-EEE/30283/2017. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by FCT

    Coeval perpendicular shortenings in the Brasilia belt : collision of irregular plate margins leading to oroclinal bending in the Neoproterozoic of central Brazil

    Get PDF
    The three belts which form the Tocantins province (central Brazil) records Neoproterozoic-EoPaleozoic collisions involving the Amazon and São Francisco paleocontinents and the Paraná continental block. The Brasília belt is a typical orocline bended around the WNW—ESE striking Pirineus Zone of High Strain (PZHS) and is comprised of the NE-trending (northern) and SE-trending (southern) segments. The Brasília dome is an N—S elliptical structural window situated in the center of the belt, at the eastern end of the PZHS. It evidences Di— D₂ and D₃ɴ shortenings (~ 750—590 Ma) due to ocean closure and Amazon- São Francisco collision following a WNW—ESE path, and demonstrates similar evolution for both segments of the belt. However, in the southern segment, D₁—D₂ structures are deformed by shortening in the SW-NE direction (D₃S). New data demonstrating D₁—D₂ and D₃ɴ tectonites deformed by D₃S struc- tures in the area close to the dome's SW margin and SE of the PZHS support understanding the Brasília belt and oroclinal bending as a consequence of the collision of two (Amazon and São Francisco) irregular continental margins leading to separation-rotation of the Paraná block from the Amazon paleocontinent and the Paraná-São Francisco collision

    A Importância na Identificação dos Fatores de Risco para Prevenção do Câncer de Mama

    Get PDF
    O câncer de mama é, provavelmente, o mais temido pelas mulheres, devido a sua elevada freqüência e, sobretudo, pelos efeitos psicológicos que as afetam, alterando a percepção da sexualidade, auto-estima e imagem pessoal. É o segundo tipo de câncer mais freqüente no mundo e o mais comum entre as mulheres. A identificação dos fatores de risco na população feminina constitui uma medida importante para a prevenção e abordagem terapêutica adequada. Foram aplicados questionários sobre fatores de risco para câncer de mama em 266 mulheres. O presente trabalho tem por objetivo a análise dos principais fatores de risco relacionados ao câncer de mama nas mulheres, objetivando a detecção precoce e o encaminhamento ao ginecologista, visando reduzir a taxa de mortalidade e, por muitas vezes, evitando a intervenção cirúrgica

    Genome-wide signatures of complex introgression and adaptive evolution in the big cats.

    Get PDF
    The great cats of the genus Panthera comprise a recent radiation whose evolutionary history is poorly understood. Their rapid diversification poses challenges to resolving their phylogeny while offering opportunities to investigate the historical dynamics of adaptive divergence. We report the sequence, de novo assembly, and annotation of the jaguar (Panthera onca) genome, a novel genome sequence for the leopard (Panthera pardus), and comparative analyses encompassing all living Panthera species. Demographic reconstructions indicated that all of these species have experienced variable episodes of population decline during the Pleistocene, ultimately leading to small effective sizes in present-day genomes. We observed pervasive genealogical discordance across Panthera genomes, caused by both incomplete lineage sorting and complex patterns of historical interspecific hybridization. We identified multiple signatures of species-specific positive selection, affecting genes involved in craniofacial and limb development, protein metabolism, hypoxia, reproduction, pigmentation, and sensory perception. There was remarkable concordance in pathways enriched in genomic segments implicated in interspecies introgression and in positive selection, suggesting that these processes were connected. We tested this hypothesis by developing exome capture probes targeting ~19,000 Panthera genes and applying them to 30 wild-caught jaguars. We found at least two genes (DOCK3 and COL4A5, both related to optic nerve development) bearing significant signatures of interspecies introgression and within-species positive selection. These findings indicate that post-speciation admixture has contributed genetic material that facilitated the adaptive evolution of big cat lineages
    corecore