1,964 research outputs found

    Design of a compact, dexterous robot hand with remotely located actuators and sensors

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    Abstract-In this work, we report on our progress in the development of a new anthropomorphic robot hand at the University of Malta. Following a brief overview of the work carried out in our laboratory so far, we discuss in some detail and through a fresh perspective a number of important lessons that can be learned from the human hand, and that can be very useful in the development of an artificial hand that can ultimately match the human counterpart in the execution of many tasks. We present a new design for a robot hand with joint position and grasping force sensing, based on the specific approaches brought up in this discussion, and targeted to reproduce many of the capabilities of the human hand. In particular, all of the actuation and sensing devices of the hand are located remotely from the device, therefore facilitating the development of a compact and lightweight hand design. A prototype of the new hand has been constructed and is presented herein. Finally, we present the initial results of our analysis to demonstrate how the magnitude and location of grasping forces can be inferred from the sensor readings

    Highly efficient planar perovskite solar cells through band alignment engineering

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    The simplification of perovskite solar cells (PSCs), by replacing the mesoporous electron selective layer (ESL) with a planar one, is advantageous for large-scale manufacturing. PSCs with a planar TiO2 ESL have been demonstrated, but these exhibit unstabilized power conversion efficiencies (PCEs). Herein we show that planar PSCs using TiO2 are inherently limited due to conduction band misalignment and demonstrate, with a variety of characterization techniques, for the first time that SnO2 achieves a barrier-free energetic configuration, obtaining almost hysteresis-free PCEs of over 18% with record high voltages of up to 1.19 V

    Spontaneous crystal coalescence enables highly efficient perovskite solar cells

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    Perovskite solar cells have recently reached staggering efficiencies, through efforts focused on reducing grain boundaries, by enlarging the size of the crystalline domains that constitute the perovskite films. Here, we demonstrate that smaller crystallites within perovskite films spontaneously coalesce into larger ones, even when complete devices are stored in the dark at room temperature. We show that crystal coalescence greatly improves the performance of state of the art perovskite solar cells. Our results reveal the dynamic nature of the morphology of perovskite films and highlight the crucial role that coalescence plays in producing highly efficient device

    Peso e rendimento dos componentes não-carcaça de ovinos terminados em pastagem nativa da Caatinga, submetidos a diferentes suplementações de sal mineral.

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    Resumo: Objetivou-se avaliar o peso e o rendimento dos componentes não-carcaças externos e internos, de ovinos em pastagem nativa da Caatinga e suplementados com diferentes suplementos minerais. Utilizaram-se 24 ovinos em terminação mestiços Santa Inês, distribuídos em um delineamento inteiramente casualisado, em três tratamentos, conforme as seguintes suplementações de sal mineral: sal mineral comercial (SALMINC), sal mineral comercial acrescido de 750 ppm de zinco animal-1 (SALMINCZn) e sal comercial com fornecimento de 2,5 ml por peso vivo metabólico (PV)0,75 animal-1 de propilenoglicol (SALMINCPeg), com oito repetições cada. Não foi observado diferenças (P>0,05) para peso e rendimento dos componentes não-carcaça externos, exceto, para peso de sangue com maior peso para SALMINCZn. Não foi verificado diferenças (P>0,05) para peso dos componentes não-carcaça internos, exceto, para peso de rins, onde foi obtido maior valor para SALMINCZn em relação a SALMINC (P0.05) for weight and yield of the noncarcass components externals, except for weight of blood with higher weight to SALMINCZn. There was not difference (P>0.05) in weight of the noncarcass components internal, except, for kidney weight, where was obtained highest value for SALMINCZn regarding SALMINC (P <0.05). For yield of the noncarcass components were observed differences only for kidneys, with higher relative value for SALMINCZn than SALMINC, and liver, where was obtained higher relative value for SALMINC than SALMINCZn (P<0.05). Supplementation with the different types of salt containing zinc or propylene glycol doesn't increase the weight of the main noncarcass components externals and internals of sheep created in native pasture of the Caatinga

    Balanço nitrogenado de caprinos alimentados com dietas contendo subproduto de urucum (Bixa orellana L.).

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    Foram avaliados os balanços nitrogenados de caprinos alimentados com dietas contendo subproduto de urucum em diferentes níveis de inclusão. Utilizaram-se doze caprinos com peso vivo inicial de 18,05 kg, distribuídos num delineamento inteiramente casualizado com quatro tratamentos e seis repetições no tempo. As inclusões de subproduto de urucum nas dietas foram de 18, 36, 46 e 72%. Os dados de consumo e digestibilidade, além dos dados de balanço nitrogenado, foram submetidos a análises de variância e regressão, em função da inclusão do subproduto na dieta. Os balanços nitrogenados em função do nível de inclusão do subproduto, apresentaram significância entre as dietas P(<0,05), apesar de todos os níveis apresentarem balanço nitrogenado positivo
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