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261.
Stefano Piazzi Lorenzo Menin Daniele Antolini Francesco Patuzzi Marco Baratieri 《International Journal of Hydrogen Energy》2021,46(13):8972-8985
This work investigates the opportunity of retrofitting existing small-scale gasifiers shifting from combined heat and power (CHP) to hydrogen and biofuels production, using steam and biomass residues (woodchips, vineyard pruning and bark). The experiments were carried out in a batch reactor at 700 °C and 800 °C and at different steam flow (SF) rates (0.04 g/min and 0.20 g/min). The composition of the producer gas is in the range of 46–70 % H2, 9–29 % CO, 12–27 % CO2, and 2–6 % CH4. A producer gas specific production factor of approx. 10 NLpg/gchar can be achieved when the lower SFs are used, which allows to provide 80 % of the hydrogen concentration required for biomethanation and MeOH synthesis. As for FT synthesis, an optimal H2/CO ratio of approx. 2 can be achieved. The results of this work provide further evidence towards the feasibility of hydrogen and biofuels generation from residual biomass through steam gasification. 相似文献
262.
Isensee Leandro José Pinheiro Adilson Detzel Daniel Henrique Marco 《Water Resources Management》2021,35(5):1499-1512
Water Resources Management - Increasing global trends in time series of annual maximum daily streamflow (AMX) raise the concern that the safety of dams and other sensitive structures is... 相似文献
263.
Alberto Reyna Marco A. Panduro Carlos del Rio-Bocio 《Expert systems with applications》2012,39(8):6872-6878
The design of an aperiodic planar array is presented in this research. This design of aperiodic arrays considers the reduction of the side lobe level and the isoflux radiation requirements for GEO (Geostationary Earth Orbit) satellite applications. In this way, it is considered four different optimization cases. The first two cases are optimizations of amplitude and phase excitations for the antenna elements in a uniform antenna array and the last two cases are optimizations of positions of the antenna elements and certain number of levels of amplitude excitation in an aperiodic array. In this case, it is proposed a simple new approach combining the main idea of both thinned theory and random arrays approaches. For this optimization problem, the well-known method of Genetic Algorithms (GA) is utilized. The obtained results show the proper performance of the array factor to provide the isoflux radiation and low side lobe level. Depending on the performance requirements, the design of the aperiodic array could lead the satellite hardware to be reduced significantly even more that results presented previously in the literature. 相似文献
264.
Marco Albertini Francesca Vallese Marilena Di Valentin Paola Berto Giorgio M. Giacometti Paola Costantini Donatella Carbonera 《International Journal of Hydrogen Energy》2014
[FeFe]-hydrogenases contain a complex [4Fe–4S]-2Fe cluster (H-cluster) and are able to efficiently reduce protons to H2. Due to their potential exploitation for renewable energy production biotechnologies, significant efforts have been put into understanding the mechanisms driving the H-cluster assembly, which involves three conserved proteins. Among them, HydF works as scaffold upon which the H-cluster precursor is synthesized and carrier to deliver it to the hydrogenase, resulting in its activation. A FeS cluster binding sequence (CxHx46-53HCxxC) is conserved in all HydF proteins and should in principle provide four ligands to coordinate the Fe atom. However, we found that alternative metal coordination may exist in different HydF proteins and that only the three cysteines are strictly required, whereas the fourth ligand may vary and is, in any case, readily exchangeable. In this work we analyzed by EPR/HYSCORE the FeS cluster proton environment of HydF from Thermotoga neapolitana to determine the possible role of surrounding residues in the non-cysteinyl iron ligation of the protein. 相似文献
265.
266.
This commentary paper aims to highlight issues associated with the supposed ability to transfer knowledge across networks. In response to the paper “Risks in Organizational Networks: An Exploratory Framework”, (Trkman and Desouza, 2012, pp. 1–17), we argue that the taken-for-granted assumption that knowledge is transferrable represents a risk in itself. We analyze knowledge in networks using a practice perspective – in turn we consider knowledge as enacted in social practices and as context-specific. In contrast with Trkman and Desouza’s paper, we argue that if knowledge is seen as enacted in practice, a framework that maps risks associated with knowledge transfer is limiting. We conclude that, since knowing in practice is emergent and not fully controllable, adopting a set of best practices on how to effectively transfer (or not) knowledge could itself be risky for managers who then believe that knowledge can be treated as a commodity and easily moved about a network. 相似文献
267.
Rachata Muneepeerakul Murad R. Qubbaj Rimjhim M. Aggarwal John M. Anderies Marco A. Janssen 《Journal of the Royal Society Interface》2012,9(77):3303-3311
Globalization and global climate change will probably be accompanied by rapid social and biophysical changes that may be caused by external forcing or internal nonlinear dynamics. These changes often subject residing populations (human or otherwise) to harsh environments and force them to respond. Research efforts have mostly focused on the underlying mechanisms that drive these changes and the characteristics of new equilibria towards which populations would adapt. However, the transient dynamics of how populations respond under these new regimes is equally, if not more, important, and systematic analysis of such dynamics has received less attention. Here, we investigate this problem under the framework of replicator dynamics with fixed reward kernels. We show that at least two types of population responses are possible—cohesive and population-dividing transitions—and demonstrate that the critical transition between the two, as well as other important properties, can be expressed in simple relationships between the shape of reward structure, shift magnitude and initial strategy diversity. Importantly, these relationships are derived from a simple, yet powerful and versatile, method. As many important phenomena, from political polarization to the evolution of distinct ecological traits, may be cast in terms of division of populations, we expect our findings and method to be useful and applicable for understanding population responses to change in a wide range of contexts. 相似文献
268.
In this paper a numerical solution is proposed for designing telescopic manipulators when workspace is prescribed through few suitable points. An algorithm is outlined by using an algebraic formulation for the workspace boundary and numerical solution is worked out by using a Newton–Raphson technique to solve a proper design problem. Numerical examples are reported to discuss computational efforts and solution characteristics. 相似文献
269.
Enhancement of phenolic compounds content and antioxidant activity of strawberry (Fragaria × ananassa) juice by block freeze concentration technology
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Wantiê T. Adorno Katia Rezzadori Giordana D. Arend Vitor C. Chaves Flávio H. Reginatto Marco Di Luccio José C.C. Petrus 《International Journal of Food Science & Technology》2017,52(3):781-787
The aim of this study was to evaluate the effects of freeze concentration of strawberry juice on content of total phenolic, anthocyanins content and antioxidant activity of the concentrated fluid and the ice obtained. An increase in the values of phenolic content was observed in the concentrate fraction for all the freeze concentration stages (five stages). The process efficiency presented a reduction when compared with the first stage, and however, the average efficiency remained around 65% in all the stages. The concentration of pelargonidin‐3‐O‐glycoside present in samples was increased in all stages. Furthermore, the antioxidant activity of the concentrated fluid of each stage, measured by DPPH and ABTS methods, was significantly higher in comparison with the juice feed. Also, antioxidant activity can be correlated with the content of pelargonidin‐3‐O‐glycoside presented in the strawberry juice. Freeze concentration can be considered a good alternative for improving the antioxidant activity of strawberry juice. 相似文献
270.
How meaty? Detection and quantification of adulterants,foreign proteins and food additives in meat products
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Marco Iammarino Rosaria Marino Marzia Albenzio 《International Journal of Food Science & Technology》2017,52(4):851-863
The worldwide consumption of meat is increasing, especially in developing countries. Many studies have correlated a diet characterised by high intake of processed red meats with a risk of colorectal cancer, stroke, coronary heart diseases and diabetes. Moreover, the quality and safety of meat products may be compromised by several admitted and not admitted procedures (i.e. addition of food additives and/or foreign proteins). For these reasons, the topic ‘meat products’ quality and safety’ has gained much in importance during last few years. In this review, the recent advances in the field of analytical methods for the evaluation of meat adulteration due to the addition of foreign proteins and food additives are reported, compared and critically evaluated. Moreover, the most representative monitoring practices, developed worldwide, related to meats adulteration are described and discussed. 相似文献