61 research outputs found

    The Teacher's Personality within the Differentiated Pedagogy

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    AbstractThe complete value of each individual personal resources is the aim of each well-organized education. Pedagogy of success is based on the need to respect everyone's needs, interests and individual availability, of everyone's rhythms and resources ensuring thus everyone's success. The present paper promotes elements of a didactic strategy adequate to the educational needs specific to different categories of students, a way to accept the differences and to cope with the diversity of human resources

    Unconventional Backup Structures Used in Smart Microgrids

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    The continuity of power supply to users is considered to be one of the main problems in the design and implementation of low-voltage smart microgrid configurations. Switching to the backup power supply, when using two frequency converters, one of which is alternately maintained in cold reserve, is presented. Switching to the backup power supply, in the case of low-voltage symmetrical smart microgrids, is another highlighted aspect. In the case of modern residential buildings, the automatic switching is necessary between two or more types of users, critical and noncritical ones to the available sources, like the public grid, photovoltaic panels, power generator, etc. Also, in this study, the implementation of smart power microgrids, featuring auto-reconfiguration, is proposed. It is considered the conversion of the public grids to active (distribution/using) smart power microgrids, which have the autoconfiguration option and use high-tech smart devices, like recloser type. Thus, the faults and contingencies will be limited or even removed, creating the frame for the supplied equipment (in a continuously increasing number due to the local and regional expansion) to operate until the removal of the fault

    New Energy Harvesting Systems Based on New Materials

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    This study starts with the ZnO nanostructured materials used for improve the efficiency of polycrystalline solar cells operation under low solar radiation conditions. The ZnO nanowires were prepared using the hydrothermal method of deposition on the seed layer by a new and complex process, with controllable morphological and optical properties. The analysis of the XRD patterns, scanning electron microscopy images (SEM) of the ZnO nanowires and a lot of tests made Pasan Meyer Burger HighLight 3 solar simulator, confirm the advantages of using the ZnO nanowires in solar cells applications for antireflection coatings. Then, piezoelectric structures based on new modified PZT zirconate titanate designed for energy harvesting applications is presented. Based on their piezoelectric characteristics, modified PZT zirconate titanate ceramics made of Pb(Zr0.53Ti0.47)0.99Nb0.01O3 ceramic have efficient applications in energy harvesting devices. A piezoelectric transducer, consisting of a thin plate of this piezoceramic material, with dimensions (34 mm × 14 mm × 1 mm), is illustrated. A multiphysics numerical simulation further illustrates such piezoelectric transducer operation. Finally, the miniature planar transformer with circular spiral winding and hybrid core—ferrite and magnetic nanofluid, designed for new energy harvesting systems is presented. We purpose now that the magnetic nanofluid be used both as a coolant and as part of the hybrid magnetic core

    Measurement of the Electrical Resistivity for Unconventional Structures

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    This study presents an apparatus for the measurement of the electrical volume resistivity of concrete structures in civil and industrial constructions in 2.5 accuracy class, which operates at 500 Hz, for measuring the in situ resistivity of concrete in the range of 5–100 Ωm that is immune to errors due to the polarization phenomena at the interface probe/concrete sample. Also, a quench protection active system (QPS), which works in tandem with a superconducting coil structures (SCSs), in order to prevent the damaging effects when the coil structures pass from the superconducting state into normal conduction state (quench), is presented. An SCS made of YBCO tape high‐temperature superconductor (HTS) type, with a critical temperature of 92 K, has been experimented. In order to minimize the heat transfer influx by convection, the SCSs are confined to a cryostat, which is vacuumed at about 0.001 mbar. The working temperature of the HTS coil structures is about 77 K, ensured by liquid nitrogen as cryogenic agent. Finally, the measurement of the electrical resistance of the sensing element (SE) as part of the resistive‐type gas sensor is shown. The SE is placed on a Wheatstone bridge. The electrical resistance of the SE is variable by an amount ΔR, on when all the resistances of a Wheatstone bridge are nominally equal

    Prototyping a Gas Sensors Using CeO2 as a Matrix or Dopant in Oxide Semiconductor Systems

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    In this chapter, two important aspects of using CeO2 in the field of gas sensors are presented. Firstly, for CO2 detection in the range of 0–5000 ppm, a binary semiconductor oxides CeO2-Y2O3 was used. Secondly, as a dopants, in oxide semiconductor systems, used to detect the NO2. In this case, CeO2 is used as a dopant in hybride composite, consisting of reduced graphene oxide/ZnO, in order to increase the sensibility in NO2 detection at low concentration in the range of 0–10 ppm. The structural and morphological characterization of sensitive materials by X-ray diffraction, SEM, adsorption desorption isotherms, thermal analysis and RAMAN spectroscopy are presented. Also, the sensing element of the sensor that detects the NO2 is achieved by depositing the nanocomposite material on the interdigital grid. The electronic conditioning signal from the sensing element is achieved by using a Wheatstone bridge together with an instrumentation operational amplifier

    Nanofluid with Colloidal Magnetic Fe3O4 Nanoparticles and Its Applications in Electrical Engineering

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    In this study, we propose a new type of a cooling agent based on magnetic nanofluid for the purpose of replacing the classical cooling fluids in electrical power transformers. The magnetite (Fe3O4) nanoparticles were synthesized by the co-precipitation method from an aqueous medium of salts FeCl3x6H2O and FeSO4x7H2O in the molar ratio Fe3+/Fe2+ = 2:1, by alkalization with 10% aqueous solution of NaOH at 80°C, for 1 h. The size of the magnetite nanoparticles, as measured by X-ray diffraction method, was 14 nm and by scanning electron microscopy (SEM), they are between 10 and 30 nm. Magnetite powder was placed in oleic acid as a surfactant to prevent agglomeration of nanoparticles. The resulting mixture was dispersed in transformer oil UTR 40, with the role of carrier liquid. The magnetic, rheological, thermal and electrical characteristic properties of the obtained Fe3O4 transformer oil-based nanofluid were determined. A mathematical model and numerical simulation results are very useful for investigating the heat transfer performances of the magnetic nanofluid. Based on this study, it was tested the cooling performance of this magnetic nanofluid for two types of electrical power transformers as compared to classical methods. We also presented a microactuator based on the same magnetic nanofluid

    The Clarity of the Information Regarding the Bioeconomy: An Analysis of the Reports Published by the Organizations

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    Bioeconomy is a material potential source of sustainable growth that calls for new approaches in research and innovation to bring about concrete improvements in Europe’s social, economic and environmental wellfare. The purpose of our research is to evaluate the clarity of reports published by organizations. The assessment of the clarity of the published reports is done for both financial and non-financial information (containing elements related to bioeconomy). The steps of this research are: (i) the investigation of the clarity of the information included in the sustainability reports, and (ii) explanation of the atypical evolution of the clarity score, using the characteristics of the cultural dimensions of the home country. We analysed 77 reports published on the websites of 17 organizations in three environmentally-sensitive activity domains in 11 countries. Using content analysis, we determine an annual score of information clarity for each organization. The results of the research show that after switching to integrated reporting in 2013 the score of information clarity was improved for 65% of the companies. Eleven organizations have a degree of information clarity for the reports published in 2013 and 2016 better than for those published in 2010. We find five atypical cases for which the score of information clarity remains the same for all the three periods under investigation. These cases have been analyzed from the point of view of the cultural characteristics existing in the organization’s home country. Through our research we provide feedback to organizations on how they can improve the clarity of their published reports

    Reviewing the use of resilience concepts in forest sciences

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    Purpose of the review Resilience is a key concept to deal with an uncertain future in forestry. In recent years, it has received increasing attention from both research and practice. However, a common understanding of what resilience means in a forestry context, and how to operationalise it is lacking. Here, we conducted a systematic review of the recent forest science literature on resilience in the forestry context, synthesising how resilience is defined and assessed. Recent findings Based on a detailed review of 255 studies, we analysed how the concepts of engineering resilience, ecological resilience, and social-ecological resilience are used in forest sciences. A clear majority of the studies applied the concept of engineering resilience, quantifying resilience as the recovery time after a disturbance. The two most used indicators for engineering resilience were basal area increment and vegetation cover, whereas ecological resilience studies frequently focus on vegetation cover and tree density. In contrast, important social-ecological resilience indicators used in the literature are socio-economic diversity and stock of natural resources. In the context of global change, we expected an increase in studies adopting the more holistic social-ecological resilience concept, but this was not the observed trend. Summary Our analysis points to the nestedness of these three resilience concepts, suggesting that they are complementary rather than contradictory. It also means that the variety of resilience approaches does not need to be an obstacle for operationalisation of the concept. We provide guidance for choosing the most suitable resilience concept and indicators based on the management, disturbance and application context

    Connecting and Harmonizing the Accounting with the Fiscal Result in Romanian Economic Entities

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    AbstractUnder the impact of the conciliation of the accounting with the taxation, the research has as an objective the dual approach of the analyzed entities’ results, respectively of the accounting and taxation ones, in order to establish the necessity of the harmonizing of the accounting and taxation information with the goal of insuring the credibility of the accounting reports for the users. Besides the accounting policies adopted in the decision process, the knowledge and the correct application of the taxation principles and rules used in determining the fiscal result makes a stamp over the accounting result. In this frame of referen ce, the research made over the presented information presented in the financial statements and from the fiscal statements referring to the mode of determination of the accounting and fiscal result have been focused on finding the answer to the next question: Under the impact of the provisions that could be applied to the economic entities from Romania the degree of connection between accounting and taxation insure the adequate harmonization of the accounting and fiscal result for the need of information of the users?
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