Recreational preferences in relation to stand treatment practice in young pedunculate oak

The aim of this study was to investigate recreational preferences for contrasting stem densities in young stands of penduculate oak. In particular, variations in preferences were examined in relation to the respondents’ affiliation with forestry and their nationality. Due to the increasing importance of oak, especially in the context of urban forests, knowledge of such preferences could have strong implications for future management practices of oak. The study was based on five pairs of colour photographs from each of five recently thinned plots in a 13-year old experiment. The plots presented five different residual stand densities: 7000 stems h

Simplified on-line monitoring system of MOSFET on-resistance based on a semi-empirical model

This work provides a solution allowing to monitor on-line the health of a power MOSFET adopted in a buck converter. In the considered application, the analysis is focused on the high-side switch, being a low-voltage power MOSFET. The monitoring system allows estimating the on-resistance of the device by measuring both output current and voltage drop across the switch. Moreover, a semi-empirical model is considered in order to account for the dependence of the on-resistance on operating temperature and gate driving voltage. The on-line implementation of such a model allows estimating on-resistance degradation in real-time with a high level of accuracy in a wide range of operating conditions. An on-line calibration procedure is also implemented in order to assess the on-resistance of fresh devices. Experimental results confirm the accuracy of the system (in conjunction with the proposed model) under different operating conditions: load current from 2A to 6A; device temperature up to 100\ub0C and gate to source voltage (VGS) from 6V to 10.5V. In the abovementioned conditions, an accuracy 642.6% is experimentally found. Hence, the system is able to properly estimate the degradation of on-resistance due to ageing conditions

“Fale Mais Sobre Isso” Como o Amor Romântico é Sentido no Corpo Humano

A monografia descrita foi fruto de um trabalho realizado em duas partes. A primeira parte, de caráter quantitativo, teve o intuito de investigar como os diferentes tipos de amor romântico influenciavam variáveis de humor e a qualidade de sono dos indivíduos, participando indivíduos que se encontravam em relacionamentos de até 2 anos (Amor Apaixonado) e indivíduos em relacionamentos com mais de 15 anos (Amor Companheiro) comparados a um grupo controle de indivíduos solteiros e que não estavam apaixonados. Foi também realizada uma coleta de amostras salivares para análise dos níveis de cortisol nos diferentes grupos estudados. A partir disso foram obtidos resultados que apresentaram níveis mais elevados de cortisol para o grupo Amor Companheiro em relação ao Grupo Solteiro e não foram encontradas diferenças nos estados de humor e padrões de sono entre os grupos estudados. A segunda parte deste trabalho é uma pesquisa qualitativa, em que se realizou entrevistas semi-estruturadas com indivíduos que se encontravam em relacionamentos estáveis de até 2 anos e que declararam estar apaixonados por seus parceiros no momento, a fim de descobrir, a partir de seus depoimentos, as sensações biológicas que o sentimento amoroso desperta. A partir dos dados coletados nas entrevistas foram obtidos relatos que eram condizentes com os estudos já realizados sobre o assunto e, portanto, foi pesquisado na literatura científica sobre o tema os fundamentos que expliquem tais respostas psicobiológicas do organismo. Também foram criadas uma nuvem de palavras com os termos mais relatados durante as entrevistas e modelos corporais que ilustram as alterações do organismo observadas pelos entrevistados devido ao sentimento de amor romântico.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq: 125620/2018-

Hardware in the loop, all-electronic wind turbine emulator for grid compliance testing

During the last years the distribution of renewable energy sources is continuously increasing and their influence on the distribution grid is becoming every year more relevant. As the increasing integration of renewable resources is radically changing the grid scenario, grid code technical requirements as are needed to ensure the grid correct behavior. To be standard compliant wind turbines need to be submitted to certification tests which usually must be performed on the field. One of the most difficult tests to be performed on the field is the low voltage ride through (LVRT) certitication due to the following resons: • The standards specify it must be performed ad different power levels. For this reasons it is necessary to wait for the right atmospheric conditions. • It requires a voltage sag generator which is usually expensive and bulky. • The voltage sag generator needs to be cabled between the grid and the wind turbine. • The voltage sag generator causes disturbances and perturbation on the power grid, for this reasons agreements with the distributor operator are needed. For all these reasons a laboratory test bench to perform the LVRT certification tests on wind turbines would be a more controlled and inexpensive alternative to the classic testing methodology. The research presented in this thesis is focused on the design and the realization of a test bench to perform certification tests on energy converters for wind turbines in laboratory. More specifically, the possibility of performing LVRT certification tests directly in laboratory over controlled conditions would allow faster testing procedures and less certification overall costs. The solution presented in this thesis is based on a power hardware in the loop implementing a digitally-controlled, power electronics-based emulation of a wind turbine. This emulator is used to drive the electronic wind energy converter (WEC) under test. A grid emulator is used to apply voltage sags to the wind turbine converter and perform LVRT certification tests. In this solution AC power supplies are used to emulate both the wind turbine and the grid emulator. For this reason the test bench power rating is limited to the AC supplies one. Two working versions of the test bench has been realized and successfully tested. The work here presented has evolved through the following phases: • Study of the grid code requirements and the state of the art. • Modeling of the parts of a wind turbine and complete system simulations

Modelling the net environmental and economic impacts of urban nature-based solutions by combining ecosystem services, system dynamics and life cycle thinking: An application to urban forests

Nature-based solutions (NBS) are gaining relevance as sustainable urban actions because of their potential to provide multiple benefits in the form of ecosystem services (ES), and thus mitigate urban challenges. This paper presents an original semi-dynamic modelling framework that simultaneously considers i) ES supply and demand dynamics, ii) negative environmental impacts, externalities, and financial costs derived from NBS, and iii) life cycle NBS impacts beyond the use phase. Compared to other models, it also aims to be valuable for urban planning actions at site level, i.e., for evaluating the net impacts of specific urban NBS projects. To validate the modelling framework, a proof-of-concept model for urban forests is developed and tested for a case study in Madrid (Spain). The modelling framework is split in two interrelated parts: foreground (dynamic modelling) and background (static modelling). In the foreground, the environmental impacts derived from the use phase of an NBS project are quantified considering its spatio-temporal dynamism, by making use of system dynamics. In the background, the environmental impacts derived from the rest of the life cycle phases of the NBS are quantified making use of steady state life cycle impact assessment. The net economic impact of the NBS project, considering both financial values and externalities, is eventually calculated in the background encompassing all the life cycle phases. Results from the case study illustrate how planning, design, and management decisions over the entire life cycle of an urban forest can influence the net environmental and economic performance of this type of NBS. A discussion is provided to inform on how the modelling framework can help moving beyond the state-of-the-art, and how the derived model can be used for sustainability assessments of urban NBS projects

A utilização de jogos como forma de ensino e aprendizagem aos alunos do ensino médio noturno na cidade de Muzambinho-MG / The use of games as a way of teaching and learning to the middle school students in the city of Muzambinho-MG

O ensino de Biologia atualmente exige um tratamento didático que direcione a atenção e o envolvimento do aluno. Portanto este texto tem como objetivo apresentar algumas considerações a partir de práticas desenvolvidas no âmbito do Programa Institucional de Bolsas de Iniciação à Docência - Ciências Biológicas do Instituto Federal de Educação, Ciência e Tecnologia do Sul de Minas Gerais - Campus Muzambinho, com alunos do ensino médio e EJA, na disciplina de Biologia, mais especificamente nos conteúdos relacionados com Zoologia. Com essa problemática fez-se o uso jogos que tinham como objetivo desenvolver uma forma diferenciada no tratamento dos conteúdos, sendo que o jogo em questão foi uma adaptação do jogo de tabuleiro conhecido como “Cara a cara” que é jogado em duplas e há a presença de um tabuleiro. Foi observado o interesse dos alunos, havendo uma competição e interação saudável entre eles, tendo assim uma troca de conhecimento. Desse modo o trabalho obteve um resultado satisfatório, principalmente na perspectiva de uma abordagem do ensino de biologia diferente do que comumente é feito