PEM single fuel cell as a dedicated power source for high-inductive superconducting coils

In practice, the voltage of a hydrogen–oxygen fuel cell is around 1 V at open circuit and from 0.6 V to 0.7 V at full rated load and it can be considered as a low-voltage energy source. Moreover, preliminary investigations undertaken on a single proton exchange membrane fuel cell (PEMFC) highlighted its behavior as a DC current source, that can be directly controlled by the H₂ flow rate when the operating point is at very low voltage. In this paper, we present an innovative application of PEMFC that relies on taking advantage of both low voltage level and current source operating mode to feed a high inductive superconducting coil. Such a coil has no resistance and among others, is very sensitive to current ripples. Thus, specific power supplies are designed to feed them but they exhibit in most cases a huge volume and/or a low energy yield. Connecting a superconducting coil to a PEMFC implies to operate in short-circuit, which is an unusual use of PEMFC. To this end, requirements of such an application are defined, by making use of a PEMFC electrical model based on a 1D analog representation of mass transport phenomena. This model, that enables to take into account the influence of gas supply conditions, notably diffusion limit operation, is directly implemented in a standard simulation software used in electrical engineering. Then, simulation results and experimental results obtained by supplying a 10 H superconducting coil cooled by liquid helium by means of a single 100 cm² PEMFC are compared and discussed.     

The influence of distance types on co-patenting and co-publishing in the USA and Europe over time

This study focuses on diverse dimensions of distance shaping collaboration in Europe and the USA during the time period 1999–2009. We take a comparative perspective by analysing two different collaboration networks (patents and publications) and two different economic areas, in order to examine differences in collaboration activities. In particular, we investigate how the collaboration intensity between regions has been influenced by spatial, technological, and cultural distance and whether these distances have lost importance over time in the distinct networks. The study adopts a panel spatial interaction modelling perspective. The results show that indeed the impact of various kinds of distances differs between Europe and the USA and changes over time.     

Parallel kd-Tree Construction on the GPU with an Adaptive Split and Sort Strategy

We introduce a parallel kd-tree construction method for 3-dimensional points on a GPU which employs a sorting algorithm that maintains high parallelism throughout construction. Typically, large arrays in the upper levels of a kd-tree do not yield high performance when computing each node in one thread. Conversely, small arrays in the lower levels of the tree do not benefit from typical parallel sorts. To address these issues, the proposed sorting approach uses a modified parallel sort on the upper levels before switching to basic parallelization on the lower levels. Our work focuses on 3D point registration and our results indicate that a speed gain by a factor of 100 can be achieved in comparison to a naive parallel algorithm for a typical scene.     

Using artificial neural networks to scale and infer vegetation media phase functions

Accurate vegetation models usually rely on experimental data obtained by means of measurement campaigns. Nowadays, RET and dRET models provide a realistic characterization of vegetation volumes, including not only in-excess attenuation, but also scattering, diffraction and depolarization. Nevertheless, both approaches imply the characterization of the forest media by means of a range of parameters, and thus, the construction of a simple parameter extraction method based on propagation measurements is required. Moreover, when dealing with experimental data, two common problems must be usually overcome: the scaling of the vegetation mass parameters into different dimensions, and the scarce number of frequencies available within the experimental data set. This paper proposes the use of Artificial Neural Networks as accurate and reliable tools able to scale vegetation parameters for varying physical dimensions and to predict them for new frequencies. This proposal provides a RMS error lower than 1 dB when compared to unbiased measured data, leading to an accurate parameter extracting method, while being simple enough for not to increase the computational cost of the model.

     

Different cell disruption methods for obtaining carotenoids by Sporodiobolus pararoseus and Rhodothorula mucilaginosa

Food Science and Biotechnology - Since carotenoids are synthesized inside the cell, it is desirable to find an efficient method to extract carotegenic pigments. This study aimed at comparing the...     

Influence of processing on the antioxidant capacity and bioactive compounds in jellies from different blackberry cultivars

The effect of thermal processing and the berry cultivar has been the subject of several studies, to serve as a basis for the least possible loss of bioactive compounds and antioxidant capacity. In Brazil, there are numerous blackberry cultivars under cultivation, and in this context, the aim of this work was to study how the bioactive compound contents and antioxidant capacity of blackberry jelly were influenced by the cultivars (Guarani, Brazos, Comanche, Tupy, Cherokee, Caingangue and Choctaw). Analysis was made of 7 fresh blackberry cultivars and 7 blackberry jelly formulations. Analysis of antioxidant activity, total phenolics, total anthocyanins and ascorbic acid was performed. It was verified that the contribution of the heat sensitive antioxidants compounds is considerable in all blackberry cultivars, and the degradation of these compounds was significantly different between the different blackberry cultivars. The Brazos and Caingangue cultivars stand out as undergoing the lowest losses in processing, resulting in jellies richer in bioactive compounds and higher antioxidant capacity.