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O objetivo deste artigo é investigar as vozes do interdiscurso na canção “História de uma gata” (Chico Buarque, 1977), que está no álbum “Os saltimbancos”, e os posicionamentos no discurso literomusical para crian- ças. A noção de intervocalidade mostrada integra o investimento vocal, ideia já desenvolvida por Mendes (2013). Apesar de analisarmos apenas uma can- ção, os resultados confirmam a hipótese de que, na MPB, encena-se um “diá- logo” entre performer e criança, visto que ambos cantam partes diferentes da letra, ao passo que, na Canção de massa para crianças, as vozes infantis são apenas uma espécie de eco que repetem o dizer dos intérpretes.

Potassium nitrate/sucrose propellant (KNSu) is a common solid propellant, which can be cold or hot crafted, employed in amateur and experimental model rockets. There is limited burning rate data available for the KNSu, particularly for the cold-crafted one. In this study, KNSu composed of 65% potassium nitrate and 35% sucrose was prepared through cold crafting and by pressing with a hydraulic press. For such a particular crafting method, we did not find any experimental data on the burning rate versus combustion pressure. Therefore, we experimentally determined the cold-crafted KNSu burning rate for pressure levels ranging from 0.9 to 7.7 bar. We employed a ballistic evaluation motor with varying nozzle diameters to obtain the desired combustion pressure. We demonstrate that the cold-crafted KNSu burning rate lies in the range of available data for the hot-crafted version. The burning rate is not sensitive to combustion pressure levels lower than 2 bar, and the combustion temperature is 98.7% of the theoretical value. We also explain the estimation the combustion pressure from the thrust-plotted curve or by using the engine burning video. [ABSTRACT FROM AUTHOR]

A novel matrix converter‐based topology to be applied in smart transformers (STs) is proposed, based on the concept of multiple modularity. To replace the conventional ST topology obtained by H‐bridge modules including DC electrolytic capacitors, the proposed ST topology uses two kinds of matrix modules to provide flexibility in the AC–AC structures to build complex ST. Fewer power semiconductor devices are used in each module to reduce the costs. The AC–AC matrix converters and the high‐frequency transformers eliminate electrolytic capacitors, enhancing ST reliability and power density. The modulation method for the proposed ST structure needs suited carrier waves and switching processes. The half‐Venturini modulation method shows several switching sequences leading to voltage imbalances in the input film capacitor divider. Therefore, the paper investigates and analyses the influence of switching sequences on the capacitor voltages in detail. The results show that the different switching sequences will cause different currents flowing into capacitors, leading to different results in capacitor voltages. Based on the analysis, proper modulations are recommended for the proposed topology. In order to verify the feasibility of the proposed topology as well as the correctness of the analysis on modulations, simulations and hardware‐in‐loop experiments are carried out. It is found that the modularity concept is feasible, and a suitable modulation sequence was developed to balance the input capacitors voltages. [ABSTRACT FROM AUTHOR]

Matrix converters have been extensively investigated in academia over the last 3 decades. Several review works targeting matrix converter topologies, commutation strategies, modulation and control techniques have been published. However, to the best of the authors' knowledge, a review on the potential contributions of matrix converters for applications that are shaping the electric power sector transition towards decarbonization is lacking, namely applications on smart grids, sustainable transportation and electrical drives. This paper presents an extensive literature review on the more relevant research works targeting applications of matrix converters as an enabling key technology for smart and resilient grids, sustainable transportation, and innovation in variable speed electric drives. [ABSTRACT FROM AUTHOR]