186,672 research outputs found
Hackenberg et al 2021
No full text5 Data sets used to validate
SimpleForest - a comprehensive tool for 3d reconstruction of trees from forest plot point clouds
Subsets:
Data containing demol in the name is originated from:
https://zenodo.org/record/4557401
and should be cited:
Demol, Miro, Gielen, Bert, & Verbeeck, Hans. (2021). QSMs, point cloud and harvest data from a destructive forest biomass experiment in Belgium using terrestrial laser scanning (Version Version 1.0) [Data set]. Zenodo. http://doi.org/10.5281/zenodo.4557401
Data containing deTanago in the name is originated from:
http://lucid.wur.nl/datasets/terrestrial-lidar-of-tropical-forests
and should be cited:
Gonzalez de Tanago, J., Lau, A., Bartholomeus, H., Herold, M., Avitabile, V., Raumonen, P. Martius, C., Goodman, R. C., Disney, M., Manuri, S., Burt, A., Calders, K. (2017). Estimation of above-ground biomass of large tropical trees with Terrestrial LiDAR. Methods in Ecology and Evolution. DOI:10.1111/2041-210X.12904
Data containing hackenberg should be cited:
Hackenberg J, Wassenberg M, Spiecker H, Sun D. Non Destructive Method for Biomass Prediction Combining TLS Derived Tree Volume and Wood Density. Forests. 2015; 6(4):1274-1300. https://doi.org/10.3390/f6041274
Data containing wytham should be cited:
Calders K, Origo N, Burt A, Disney M, Nightingale J, Raumonen P Åkerblom M, Malhi Y and Lewis P. Realistic Forest Stand Reconstruction from Terrestrial LiDAR for Radiative Transfer Modelling. Remote Sensing; 2018; 10(6): 10.3390/rs10060933.
Data containing leibzig gives credit to:
The clouds's origin: Leipzig Canopy Crane facility financed by the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig.
The clouds's owner: Systematic Botany and Functional Biodiversity, Institute for Biology, Leipzig University
Numerical studies of the automatic control of Boundary-Layer transition via multiple suction panels
No full textA numerical algorithm is introduced for the optimization of the suction distribution to maintain transition at a desired position for a flow over a flat plate with a smooth two-dimensional hump and an array of suction panels. The computation consists of the calculation of the interacting boundary-layer flow, the determination of the spatial growth rates of the disturbance waves, the prediction of the transition location via the eN-method and finally of the optimization of the suction flow rates using a modified least mean-squares algorithm. The optimization algorithm has been successfully applied to plates with two or four suction panels. The results show clearly that the pressure distribution has a highly significant effect on the optimum suction distribution over the plate. The numerical code shows its potential to be applied to laminar flow control aerofoils to determine the optimum suction distribution for given flight conditions.</p
Gradient-based control and optimization of boundary layer transition
No full textIn flow past bodies, small amounts of surface suction can delay the transition from laminar to turbulent flow. Suction therefore has significant potential to reduce the drag and hence the operating costs of aircraft. To obtain best results the suction distribution must be optimized, and, if necessary, should be adjusted to take account of changing conditions. Here distributed suction is used through a number of independently controlled discrete suction panels, with transition maintained at a desired location while an automatic adaptive control feedback loop regulates the suction flowrates. The combination of minimum suction effort with constant transition position is expressed as a constrained optimization problem. A gradient-based algorithm is used to perform the control and optimization. Up to six suction panels are used, and flows both with and without an imposed pressure gradient are considered. In simple cases the method converges rapidly, but in other situations there is no single optimum solution within the numerical tolerance of the method. There are also cases in which an optimum solution exists but cannot be achieved as it occurs at a discontinuity in the relationship between the transition position and the suction flowrates. Similar problems could occur with other cost functions and formulations, and when using different solution algorithms
Numerical optimization of the suction distribution for laminar flow control aerofoils
No full textIn recent years there has been an increasing interest in the search of methods for drag reduction on aircraft. A promising technique for the reduction of the skin-friction drag is to postpone transition from laminar to turbulent flow using either suction - Laminar Flow Control - or suction plus a favourable pressure gradient - Hybrid Laminar Flow Control. However, for an efficient application of these concepts, the suction distribution has to be optimized to ensure that the gain in drag reduction exceeds the power penalty. In this thesis a numerical algorithm has been developed to optimize the suction distribution over several independent suction panels either while maintaining transition at a desired location or while minimizing the overall power consumption. The numerical code comprises four steps; the calculation of the boundary-layer flow, the determination of the spatial amplification factors of the two-dimensional Tollmien-Schlichting waves, the prediction of the transition location via the eN-method, and finally, the optimization of the suction flow rates. Optimizing the suction distribution while maintaining transition at a desired location can be expressed as a constrained optimization problem, which is solved using an adaptive algorithm based on the gradient projection method. The numerical solution of this problem is very intensive computationally, therefore the use of parallel computation techniques is of advantage. The numerical code has first been applied to flat-plate boundary layers with zero and non-zero pressure gradients and up to eight suction panels, and later to flows over NACA aerofoil sections. Comparison with experimental results has permitted the validation of the code. The results show that suction is a suitable means for the postponement of transition. The optimum suction distribution has been found to be strongly dependent on the pressure distribution, the configuration of the suction panels and the desired transition location.(DX184260)</p
Thiourea priming enhances salt tolerance through co-ordinated regulation of microRNAs and hormones in Brassica juncea
No full textActivation of stress tolerance mechanisms demands transcriptional reprogramming. Salt stress, a
major threat to plant growth, enhances ROS production and affects transcription through modulation
of miRNAs and hormones. The present study delineates salt stress ameliorating action of thiourea
(TU, a ROS scavenger) in Brassica juncea and provides mechanistic link between redox, microRNA and
hormones. The ameliorative potential of TU towards NaCl stress was related with its ability to decrease
ROS accumulation in roots and increase Na+ accumulation in shoots. Small RNA sequencing revealed
enrichment of down-regulated miRNAs in NaCl+TU treated roots, indicating transcriptional activation.
Ranking analysis identified three key genes including BRX4, CBL10 and PHO1, showing inverse
relationship with corresponding miRNA expression, which were responsible for TU mediated stress
mitigation. Additionally, ABA level was consistently higher till 24h in NaCl, while NaCl+TU treated
roots showed only transient increase at 4h suggesting an effective stress management. Jasmonate and
auxin levels were also increased, which prioritized defence and facilitated root growth, respectively.
Thus, the study highlights redox as one of the “core” components regulating miRNA and hormone
levels, and also strengthens the use of TU as a redox priming agent for imparting crop resilience to salt
stres
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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