314 research outputs found

    Las órdenes militares en la cruzada granadina de Alfonso el Benigno (1329-1334)

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    A la memoria de la Dra. Regina Sainz de la MazaEn este estudio se recupera la investigación las Órdenes militares catalanoaragonesas durante el siglo XIV. El interés del trabajo radica en el hecho de que en él se considera, de manera conjunta, la actuación en la cruzada de las cuatro Órdenes militares enclavadas en territorio catalanoaragonés, lo cual permite observar tanto su distinto grado de participación como la diferente actitud del monarca hacia cada una de ellas.Peer reviewe

    Expression system of CotA-laccase for directed evolution and high-throughput screenings for the oxidation of high-redox potential dyes

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    Laccases are useful biocatalysts for many diverse biotechnological applications. In this study we have established efficient and reliable expression systems and high-throughput screenings for the recombinant CotA-laccase from Bacillus subtilis. The expression levels of cotA-laccase were compared in five different Escherichia coli host strains growing in 96-well microtiter plates under different culture conditions. Lower coefficients of variance (around 15%) were achieved using crude cell lysates of BL21 and KRX host strains growing under microaerobic conditions. Reproducible high-throughput screenings for the decolorization of high redox potential azo and anthraquinonic dyes were developed and optimized for identification of variants with increased redox potential. The enzymatic assays developed were tested for the screening of one mutant library from CotA-laccase created by error-prone PCR.(undefined

    Das Jubiläumsjahr im Überblick

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    Das Staatsarchiv Hamburg feierte 2010 sein 300-jähriges Bestehen. Sein Vorläufer wurde bereits im Jahre 1293 erstmals erwähnt und somit die Aufbewahrung wichtiger Dokumente der Stadt an zentraler Stelle bezeugt. Doch erst seit dem 11. September 1710, dem Amtsantritt von Nicolaus Stampeel als wissenschaftlicher Archivar bei der Stadt Hamburg, werden Dokumente systematisch ausgewählt, bewahrt und erschlossen. Dieses Jubiläum hat das Staatsarchiv mit einem breit gefächerten Veranstaltungsprogramm begangen, zu dem auch Vorträge und Lesungen gehörten, die in der hier vorliegenden Festschrift abgedruckt sind.In 2010, the Hamburg State Archives celebrated its 300th anniversary. The Archives\u27 forerunner was first mentioned in 1293 and thus testified to the preservation of important documents of the city in a central place. But it was not until September 11th, 1710, when Nicolaus Stampeel took office as a scientific archivist at the City of Hamburg. From then on, documents were systematically selected, preserved and indexed. This anniversary was celebrated by the State Archives with a broad programme of events, which included lectures and readings printed in the commemorative volume available here

    Das Jubiläumsjahr im Überblick

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    Das Staatsarchiv Hamburg feierte 2010 sein 300-jähriges Bestehen. Sein Vorläufer wurde bereits im Jahre 1293 erstmals erwähnt und somit die Aufbewahrung wichtiger Dokumente der Stadt an zentraler Stelle bezeugt. Doch erst seit dem 11. September 1710, dem Amtsantritt von Nicolaus Stampeel als wissenschaftlicher Archivar bei der Stadt Hamburg, werden Dokumente systematisch ausgewählt, bewahrt und erschlossen. Dieses Jubiläum hat das Staatsarchiv mit einem breit gefächerten Veranstaltungsprogramm begangen, zu dem auch Vorträge und Lesungen gehörten, die in der hier vorliegenden Festschrift abgedruckt sind.In 2010, the Hamburg State Archives celebrated its 300th anniversary. The Archives\u27 forerunner was first mentioned in 1293 and thus testified to the preservation of important documents of the city in a central place. But it was not until September 11th, 1710, when Nicolaus Stampeel took office as a scientific archivist at the City of Hamburg. From then on, documents were systematically selected, preserved and indexed. This anniversary was celebrated by the State Archives with a broad programme of events, which included lectures and readings printed in the commemorative volume available here

    Improved Impingement Cooling Using Flow Enhancing Structural Elements

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    This investigation is part of a study seeking to improve impingement cooling in internal combustion turbomachinery using flow modifying elements within the cooling channel. A simplified geometry of a jet impingement cooling configuration is chosen for well-defined numerical simulations and complementary experiments. The generic cooling channel setup features of a square cross-section that is closed on one end and is supplied by 9 inline jets that are directed toward a heated plate. Using RANS, the presence of an arc-conic placed immediately downstream of each jet nozzle was found to increase the heat transfer and prompted the present experimental study to elucidate the fluid mechanical mechanisms leading to the improved performance. Central to the study is an extensive data base of time-resolved 2d-2c PIV data for both channel configurations, with and without installed arc-conics, on a field of view that simultaneously captures up to 3 jets. Using two-point correlations, an interaction or modal coupling between the jets is not observed, suggesting that each jet may be treated individually. The arc-conics tend to stabilize the jets by capturing and redirecting the bulk cross-flow, thereby increasing the self-similarity of the jet impingement pattern, in particular toward the channel exit. Modal analysis using both snap-shot POD and spectral POD (SPOD) capture the dynamics of the flow, ideally to achieve a dimensionality reduction for reduced order modeling. However, the fully turbulent flow with highly stochastic dynamics exhibits only weak spatial or temporal signatures, with the energy content spread across a large number of modes. Among the dominant modes are pulsations of the jet onto the surface along with spanwise sweeping motions. The stabilization of the jet by the arc-conic results in a more defined impingement flow with the signature of the jet's shear layer visible in the higher modes of the energy spectrum and is considered the main mechanism of improved heat transfer

    Cooling Model Calibration in a Collaborative Turbine Preliminary Design Process Using the NASA Energy Efficient Engine Part II: 1D Turbine Modeling

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    Accurately estimating turbine cooling requirements at a preliminary design stage is crucial for modeling the overall propulsive system. The operating conditions of compressor, combustor and turbine are significantly influenced by these requirements. Empirical cooling models have thus far provided reliable initial estimations. For next-generation aero-engines this solution becomes inadequate. To address this challenge, an alternative semi-empirical approach based on an established cooling model is built into a collaborative turbine design tool chain. This cooling model is applied to the two cooled high-pressure turbines developed by P&W and GE within the NASA E3 program for both validation and to provide calibrated model parameters for future studies. Finally, sensitivity analysis provide a better understanding on how cooling requirements can be reduced through turbine preliminary design decisions, material and cooling technologies. This work focuses on 1D turbine studies with an accompanying paper on 0D engine modeling

    Pseudo Natural Products—Chemical Evolution of Natural Product Structure

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    Pseudo‐natural products (PNPs) combine natural product (NP) fragments in novel arrangements not accessible by current biosynthesis pathways. As such they can be regarded as non‐biogenic fusions of NP‐derived fragments. They inherit key biological characteristics of the guiding natural product, such as chemical and physiological properties, yet define small molecule chemotypes with unprecedented or unexpected bioactivity. We iterate the design principles underpinning PNP scaffolds and highlight their syntheses and biological investigations. We provide a cheminformatic analysis of PNP collections assessing their molecular properties and shape diversity. We propose and discuss how the iterative analysis of NP structure, design, synthesis, and biological evaluation of PNPs can be regarded as a human‐driven branch of the evolution of natural products, that is, a chemical evolution of natural product structure

    Investigating the Unsteady Dynamics of a Multi-Jet Impingement Cooling Flow Using Large Eddy Simulation

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    We investigate the unsteady behavior of an in-line jet impingement array of nine jets at a Reynolds number of 10,000 in a narrow channel subjected to a developing cross flow of up to 25% of the bulk jet velocity. To this end, we present an improved version of a previously published large eddy simulation (LES) now with resolved turbulence at the inflow boundaries. After a careful analysis of the transient behavior and statistical convergence of the LES, we discuss the time-averaged heat transfer characteristics of the configuration compared to numerical references of similar configurations. We then show how the large-scale unsteadiness increases from jet to jet. Both space-only and spectral proper orthogonal decompositions (POD and SPOD) are used to discuss the large-scale organization of single jets and multiple jets in combination. The latter shows a qualitative change in the unsteady behavior of the temperature footprint on the impingement wall with increasing cross flow

    Experimental and Numerical Investigation of a Multi-Jet Impingement Cooling Configuration

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    In order to protect turbine blades from thermal damage or thermally induced aging, internal impingement cooling has found common use throughout engine design, both in stationary gas turbines as well as aircraft engines, but also finds applications in other areas requiring cooling. The present investigation is focused on a generic impingement cooling configuration that can be easily modelled with computational fluid dynamics (CFD) and at the same time can be studied in detail experimentally. The acquired experimental data can be directly used for the validation of the CFD simulations, ultimately allowing their application in more complex, realistic configurations where experimental investigations become prohibitively expensive or otherwise impossible. The investigated configuration consists of 9 evenly spaced jets of Reynolds number Re D = 10000 issuing into a square channel that is sealed at one end. The jets directly impinge on a uniformly heated target plate. With previous work on similar configurations well described in literature, the focus of the present contribution is to further exploit the potentials offered by snap-shot based and time-resolved measurements. The flow field within the channel is characterized with both conventional, snap-shot particle image velocimetry (PIV) as well as with high-speed, time-resolved PIV (TR-PIV) to, respectively, capture overview data as well as detailed information on temporally evolving flow structures. In addition, measurements of the unsteady surface temperature distribution on the heated channel wall are performed by means of a newly developed unsteady temperature sensitive paint (iTSP) measurement technique. The interaction of the turbulent jets with the wall and with its neighbors is studied in detail using correlation and spectral analysis as well as modal decomposition. Where possible, this is supplemented with corresponding data obtained from numerical modelling. None of the applied postprocessing methods reveal a significant interaction between jets suggesting that the jet-driven dynamics of heat transfer at the wall are restricted to their immediate vicinity which may simplify the requirements on numerical models of similar cooling configurations

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    Das Staatsarchiv Hamburg feierte 2010 sein 300-jähriges Bestehen. Sein Vorläufer wurde bereits im Jahre 1293 erstmals erwähnt und somit die Aufbewahrung wichtiger Dokumente der Stadt an zentraler Stelle bezeugt. Doch erst seit dem 11. September 1710, dem Amtsantritt von Nicolaus Stampeel als wissenschaftlicher Archivar bei der Stadt Hamburg, werden Dokumente systematisch ausgewählt, bewahrt und erschlossen. Dieses Jubiläum hat das Staatsarchiv mit einem breit gefächerten Veranstaltungsprogramm begangen, zu dem auch Vorträge und Lesungen gehörten, die in der hier vorliegenden Festschrift abgedruckt sind.In 2010, the Hamburg State Archives celebrated its 300th anniversary. The Archives\u27 forerunner was first mentioned in 1293 and thus testified to the preservation of important documents of the city in a central place. But it was not until September 11th, 1710, when Nicolaus Stampeel took office as a scientific archivist at the City of Hamburg. From then on, documents were systematically selected, preserved and indexed. This anniversary was celebrated by the State Archives with a broad programme of events, which included lectures and readings printed in the commemorative volume available here
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