1,191 research outputs found

    Distribution of Complex and Core Lipids within New Hyperthermophilic Members of the Archaea Domain

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    Core and complex lipids of several new hyperthermophilic archaeal isolates were analyzed. The organisms belong to the Sulfolobales,Archaeoglobus, Pyrobaculum, and Methanococcus. A detailed structural investigation of complex lipids of Pyrobaculum species is reported. The different lipid structures are of help for a rapid and simple phylogenetic classification of the new isolates. They are in agreement with the classification based on other features

    A new physarum learner for network structure learning from biomedical data

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    A novel structure learning algorithm for Bayesian Networks based on a Physarum Learner is presented. The length of the connections within an initially fully connected Physarum-Maze is taken as the inverse Pearson correlation coefficient between the connected nodes. The Physarum Learner then estimates the shortest indirect paths between each pair of nodes. In each iteration, a score of the surviving edges is incremented. Finally, the highest scored connections are combined to form a Bayesian Network. The novel Physarum Learner method is evaluated with different configurations and compared to the LAGD Hill Climber showing comparable performance with respect to quality of training results and increased time efficiency for large data sets

    Lifetime Extension, Repowering or Decommissioning? Decision Support for Operators of Ageing Wind Turbines

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    In Germany, more than one third of the installed wind energy capacity will leave the feed-in tariff funding between 2021 and 2025. Operators of affected turbines are therefore increasingly concerned with the design of profitable end-of-funding strategies. This requires feasibility analyses of both lifetime extension and repowering options and entails the subsequent challenge to determine the optimal lifetime extension and corresponding repowering timing. To support operators and other stakeholders dealing with wind turbines' end-of-life issues, this study presents a geographic information system that permits evaluating optimal end-of-funding strategies at different spatial scales reaching down to detailed analyses on individual turbine level. The decision support system processes topographic, wind, turbine, and finance data in an integrated system of resource simulations, spatial planning analyses and economic viability assessments. Case-study results show that a uniform end-of-funding strategy cannot be applied to all ageing turbines. Conducted sensitivity analyses rather indicate that the best strategy highly depends on various turbine-specific aspects, especially the location, type and maintenance costs as well as exogenous factors, including the developments of electricity spot market prices and tendered feed-in premiums. In light of latest trends regarding the exogenous factors, lifetime extension and repowering potentials increase. However, the results also indicate that dismantling, disposal and recycling of numerous ageing turbines will become a major challenge for the wind energy sector in the next decade. © 2019 Published under licence by IOP Publishing Ltd

    The vanishing ideal of a finite set of points with multiplicity structures

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    Given a finite set of arbitrarily distributed points in affine space with arbitrary multiplicity structures, we present an algorithm to compute the reduced Groebner basis of the vanishing ideal under the lexicographic ordering. Our method discloses the essential geometric connection between the relative position of the points with multiplicity structures and the quotient basis of the vanishing ideal, so we will explicitly know the set of leading terms of elements of I. We split the problem into several smaller ones which can be solved by induction over variables and then use our new algorithm for intersection of ideals to compute the result of the original problem. The new algorithm for intersection of ideals is mainly based on the Extended Euclidean Algorithm.Comment: 12 pages,12 figures,ASCM 201

    Periodic Aerodynamic Response of Axial Fan Rotor Blades to Nonuniform Inlet Flow Fields

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    Abstract An experimental investigation of the aerodynamic response of the rotor blading of a single stage low speed axial research compressor, which was exposed to wake type inlet flow disturbances was carried out at the Institute's low speed compressor and fan research facility. The investigation comprised 5 hole pressure probe surveys of the nonuniform flow field at the rotor inlet and exit planes as well as direct recording of the unsteady surface pressure response by rotor blade mounted `fast response' miniature pressure transducers. Forcing functions in terms of streamwise and transverse gust velocities were • determined from the circumferential and radial distribution of the inlet flow properties. The blade surface pressure history of the unsteady aerodynamic response was recorded at several locations along span and along chord. The influence of steady stage loading on the forcing function as well as on the unsteady rotor blade response was investigated. At midspan the recorded local blade surface pressure histories were integrated to a spanwise unsteady blade force coefficient, which was correlated to a calculated force coefficient determined by a twodimensional linearized tmsteady aerodynamic analysis

    Equilibrium and non-equilibrium effects in relativistic heavy ion collisions

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    The hypothesis of local equilibrium (LE) in relativistic heavy ion collisions at energies from AGS to RHIC is checked in the microscopic transport model. We find that kinetic, thermal, and chemical equilibration of the expanding hadronic matter is nearly reached in central collisions at AGS energy for t >_ fm/c in a central cell. At these times the equation of state may be approximated by a simple dependence P ~= (0.12-0.15) epsilon. Increasing deviations of the yields and the energy spectra of hadrons from statistical model values are observed for increasing bombarding energies. The origin of these deviations is traced to the irreversible multiparticle decays of strings and many-body (N >_ 3) decays of resonances. The violations of LE indicate that the matter in the cell reaches a steady state instead of idealized equilibrium. The entropy density in the cell is only about 6% smaller than that of the equilibrium state

    Rollator usage lets young individuals switch movement strategies in sit-to-stand and stand-to-sit tasks

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    \ua9 2023, Springer Nature Limited.The transitions between sitting and standing have a high physical and coordination demand, frequently causing falls in older individuals. Rollators, or four-wheeled walkers, are often prescribed to reduce lower-limb load and to improve balance but have been found a fall risk. This study investigated how rollator support affects sit-to-stand and stand-to-sit movements. Twenty young participants stood up and sat down under three handle support conditions (unassisted, light touch, and full support). As increasing task demands may affect coordination, a challenging floor condition (balance pads) was included. Full-body kinematics and ground reaction forces were recorded, reduced in dimensionality by principal component analyses, and clustered by k-means into movement strategies. Rollator support caused the participants to switch strategies, especially when their balance was challenged, but did not lead to support-specific strategies, i.e., clusters that only comprise light touch or full support trials. Three strategies for sit-to-stand were found: forward leaning, hybrid, and vertical rise; two in the challenging condition (exaggerated forward and forward leaning). For stand-to-sit, three strategies were found: backward lowering, hybrid, and vertical lowering; two in the challenging condition (exaggerated forward and forward leaning). Hence, young individuals adjust their strategy selection to different conditions. Future studies may apply this methodology to older individuals to recommend safe strategies and ultimately reduce falls
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