Model-based analysis for the thermal management of open-cathode proton exchange membrane fuel cell systems concerning efficiency and stability

In this work we present a dynamic, control-oriented, concentrated parameter model of an open-cathode proton exchange membrane fuel cell system for the study of stability and efficiency improvement with respect to thermal management. The system model consists of two dynamic states which are the fuel cell temperature and the liquid water saturation in the cathode catalyst layer. The control action of the system is the inlet air velocity of the cathode air flow manifold, set by the cooling fan, and the system output is the stack voltage. From the model we derive the equilibrium points and eigenvalues within a set of operating conditions and subsequently discuss stability and the possibility of efficiency improvement. The model confirms the existence of a temperature-dependent maximum power in the moderate temperature region. The stability analysis shows that the maximum power line decomposes the phase plane in two parts, namely stable and unstable equilibrium points. The model is capable of predicting the temperature of a stable steady-state voltage maximum and the simulation results serve for the design of optimal thermal management strategies.Postprint (author's final draft

European Regional Space Classification Regarding Smart Growth Level

The paper presented classification results including European regional space positional statistics regarding advancement and smart growth level in NUTS 2 regions. Regional smart growth covers three pillars: innovation, creativity (Knowledge Based Economy) and smart specialization illustrated by characteristics available in Eurostat data resources. These qualities constituted the basis for constructing aggregate measures for specific pillars and also for the purposes of regional classification. The results of obtained classes were assessed in an overall European space, in groups of regions distinguished in line with integration processes chronology and also in capital regions and these including the country capital, as well as in the system of Polish regions.Strategia Europa 2020, jako sukcesor Strategii Lizbońskiej, jest wizją społecznej gospodarki rynkowej dla Europy XXI wieku, obejmującą trzy powiązane priorytety: 1/ rozwój inteligentny: rozwój gospodarki opartej na wiedzy i innowacji; 2/ rozwój zrównoważony: wspieranie gospodarki efektywniej korzystającej z zasobów, bardziej przyjaznej środowisku i bardziej konkurencyjnej; 3/ rozwój sprzyjający włączeniu społecznemu: wspieranie gospodarki o wysokim poziomie zatrudnienia, zapewniającej spójność społeczną i terytorialną. W pracy przedstawiono wyniki klasyfikacji ze statystykami pozycyjnymi europejskiej przestrzeni regionalnej ze względu na stopień zaawansowania i poziom inteligentnego rozwoju w regionach szczebla NUTS 2. Rozwój inteligentny regionów uwzględnia trzy filary: innowacyjność, kreatywność (Gospodarka Oparta na Wiedzy) i inteligentną specjalizację ilustrowane charakterystykami znajdującymi się w zasobach informacyjnych Eurostatu. Cechy te stanowiły podstawę do konstrukcji miar agregatowych dla określonych filarów, a także do klasyfikacji regionów. Wyniki uzyskanych podziałów oceniono w całej europejskiej przestrzeni regionalnej, w grupach regionów wydzielonych zgodnie z chronologią procesów integracji, a także w regionach stołecznych i zawierających stolicę oraz w układzie regionów polskich

A code to unfold scintillation spectrometer polyenergetic gamma photon experimental distributions

FORTRAN code to unfold sodium iodide scintillation spectrometer polyenergetic gamma photon experimental distribution

A regional analysis of CAP expenditure in Austria

This paper reflects the demand for taking account of the territorial dimension in the application of Common Agricultural Policy (CAP) more comprehensively. While this has been addressed in rural development discourse to a wide extent over the last two decades and consensus for regionalized strategies is emerging, programme evaluation is in general still limited to the analysis of policy interventions at the national level. This implies that conclusions on the territorial effects of CAP are largely missing. Therefore the intention of this paper is to provide a regional analysis of CAP expenditures for pillar 1 and pillar 2, and to demonstrate and assess their actual territorial impacts, represented on the basis of the NUTS 3 region ‘Obersteiermark West’: The territorial analysis presented is an example to reduce this gap (national vs territorial) in the evaluation of CAP.CAP expenditure, regional analysis, territorial effectiveness, Agricultural and Food Policy, Q18,

The Old General Store

Non-fiction by Anita Strah

Temperature control of open-cathode PEM fuel cells

Proper temperature control of Proton Exchange Membrane (PEM) Fuel Cells is a crucial factor for optimizing fuel cell performance. A robust temperature controller is required for optimal water management of PEM fuel cells. This paper describes a model-based characterization of the equilibrium points of an open-cathode fuel cell system as the baseline for proper controller design, highlighting the relation between fuel cell temperature, humidification and performance. Phase plane analysis of the nonlinear model versus a linearized model around different points of operation shows the potential of approximating the nonlinear system behavior with a linear model. The methodology for the system analysis presented in this paper finally serves for the development of control schemes using robust control techniques. The designed controller is validated in simulation with the nonlinear plant model.Postprint (published version

Binding to medium and long chain fatty acyls is a common property of HEAT and ARM repeat modules.

Covalent post-translational modification (PTM) of proteins with acyl groups of various carbon chain-lengths regulates diverse biological processes ranging from chromatin dynamics to subcellular localization. While the YEATS domain has been found to be a prominent reader of acetylation and other short acyl modifications, whether additional acyl-lysine reader domains exist, particularly for longer carbon chains, is unclear. Here, we employed a quantitative proteomic approach using various modified peptide baits to identify reader proteins of various acyl modifications. We discovered that proteins harboring HEAT and ARM repeats bind to lysine myristoylated peptides. Recombinant HEAT and ARM repeats bind to myristoylated peptides independent of the peptide sequence or the position of the myristoyl group. Indeed, HEAT and ARM repeats bind directly to medium- and long-chain free fatty acids (MCFA and LCFA). Lipidomic experiments suggest that MCFAs and LCFAs interact with HEAT and ARM repeat proteins in mammalian cells. Finally, treatment of cells with exogenous MCFAs and inhibitors of MCFA-CoA synthases increase the transactivation activity of the ARM repeat protein β-catenin. Taken together, our results suggest an unappreciated role for fatty acids in the regulation of proteins harboring HEAT or ARM repeats

Variation in the flowering time orthologs BrFLC and BrSOC1 in a natural population of Brassica rapa.

Understanding the genetic basis of natural phenotypic variation is of great importance, particularly since selection can act on this variation to cause evolution. We examined expression and allelic variation in candidate flowering time loci in Brassica rapa plants derived from a natural population and showing a broad range in the timing of first flowering. The loci of interest were orthologs of the Arabidopsis genes FLC and SOC1 (BrFLC and BrSOC1, respectively), which in Arabidopsis play a central role in the flowering time regulatory network, with FLC repressing and SOC1 promoting flowering. In B. rapa, there are four copies of FLC and three of SOC1. Plants were grown in controlled conditions in the lab. Comparisons were made between plants that flowered the earliest and latest, with the difference in average flowering time between these groups ∼30 days. As expected, we found that total expression of BrSOC1 paralogs was significantly greater in early than in late flowering plants. Paralog-specific primers showed that expression was greater in early flowering plants in the BrSOC1 paralogs Br004928, Br00393 and Br009324, although the difference was not significant in Br009324. Thus expression of at least 2 of the 3 BrSOC1 orthologs is consistent with their predicted role in flowering time in this natural population. Sequences of the promoter regions of the BrSOC1 orthologs were variable, but there was no association between allelic variation at these loci and flowering time variation. For the BrFLC orthologs, expression varied over time, but did not differ between the early and late flowering plants. The coding regions, promoter regions and introns of these genes were generally invariant. Thus the BrFLC orthologs do not appear to influence flowering time in this population. Overall, the results suggest that even for a trait like flowering time that is controlled by a very well described genetic regulatory network, understanding the underlying genetic basis of natural variation in such a quantitative trait is challenging

Water transport study in a high temperature proton exchange membrane fuel cell stack

A study of water transport in a high temperature phosphoric acid doped polybenzimidazole (PBI) membrane fuel cell stack is reported. Tests with different stoichiometries of dry cathode and different humidity levels of anode are performed. It is found that water transport across the membrane electrode assembly (MEA) is noteworthy and that water vapor partial pressure on the anode outlet is almost always higher than on the cathode outlet, even when using dry hydrogen. The water transport is a strong function of current density but it also depends on stoichiometry and humidity level. In a series of tests with dry nitrogen on one side and humid nitrogen on the other side, the membrane's water permeability coefficient is determined to be 2.4 × 10-13 mol s-1 cm-1 Pa-1 at 160 °C which is more than an order of magnitude higher than the values previously reported in the literature. Also, the results indicate that the permeability coefficient might be relative humidity dependent and could even be somewhat higher than the value reported here, but further investigation is needed. The experimental findings are reproduced and explained with a 2D steady state computational fluid dynamics (CFD) model. Internal water transport profiles across the membrane and along the gas flow channels are presented and discussed.This work is partially funded by the project of CICYTDPI2011-25649 MICINN. Finally, the authors highly appreciate the support of the Institut de Robòtica i Informàtica Industrial in enabling a research stay of Dario Bezmalinović at the Fuel Cell Laboratory in Barcelona.Peer Reviewe