Roots of Stylosanthes hamata create macropores in the compact layer of a sandy soil

Abstract The paper presents results of a field experiment designed to investigate the potential use of forage legume Stylosanthes hamata (stylo) to ameliorate the structure of a compact layer in sandy soils of Northeast Thailand. Sandy and acidic soils that are common to Northeast Thailand have restricted agronomic potential due to inherent chemical and physical properties. A compact layer at 20-40 cm reduces root elongation for most crops, thereby restricting the quantity of nutrients and water available for the plant growth. Deep ploughing and subsoiling are costly and have not been shown to be effective in overcoming compaction since these soils are unstable and collapse after the first heavy rainfall event. A three-year study was conducted in order to evaluate the effect of continuous stylo on the porosity of the compact layer and its influence on root elongation and yield of a subsequent maize crop. Continuous stylo was grown for two years in experimental plots and compared to a currently used stylo-maize rotation. Root distribution and macropore density were measured under the two cropping systems. After 24 months of continuous stylo, roots were able to penetrate the compact layer, resulting in a significant improvement in the macroporosity of this layer. The subsequent maize crop developed a deeper and more extensive root system using macropores created after 24 months of continuous stylo when compared to the stylo-maize rotation treatment. This study demonstrates the potential role of Stylosanthes hamata in structural amelioration of sandy compact layers

Noble gases and radiocarbon in natural gases

In samples of pure natural gas hydrates from Hydrate Ridge, Cascadia Margin, virtually no helium and neon components are present providing evidence that the light noble gases are not incorporated into the structure of natural methane hydrates. In contrast, the hydrates contain significant amounts of argon, krypton and xenon. These gases show a distinct fractionation pattern, with the heavier ones preferentially incorporated into the gas hydrate structure. The hydrate methane is devoid of 14C indicating that there is no contribution of a recent (14C-active) organic carbon reservoir to the hydrate carbon pool. On the basis of the δ13C and δ2H signature, it appears that microbial CO2-reduction is the dominant CH4 production pathway

Incorporating field wind data to improve crop evapotranspiration parameterization in heterogeneous regions

Accurate parameterization of reference evapotranspiration ( ET0) is necessary for optimizing irrigation scheduling and avoiding costs associated with over-irrigation (water expense, loss of water productivity, energy costs, and pollution) or with under-irrigation (crop stress and suboptimal yields or quality). ET0 is often estimated using the FAO-56 method with meteorological data gathered over a reference surface, usually short grass. However, the density of suitable ET0 stations is often low relative to the microclimatic variability of many arid and semi-arid regions, leading to a potentially inaccurate ET0 for irrigation scheduling. In this study, we investigated multiple ET0 products from six meteorological stations, a satellite ET0 product, and integration (merger) of two stations’ data in Southern California, USA. We evaluated ET0 against lysimetric ET observations from two lysimeter systems (weighing and volumetric) and two crops (wine grapes and Jerusalem artichoke) by calculating crop ET ( ETc) using crop coefficients for the lysimetric crops with the different ET0. ETc calculated with ET0 products that incorporated field-specific wind speed had closer agreement with lysimetric ET, with RMSE reduced by 36 and 45% for grape and Jerusalem artichoke, respectively, with on-field anemometer data compared to wind data from the nearest station. The results indicate the potential importance of on-site meteorological sensors for ET0 parameterization; particularly where microclimates are highly variable and/or irrigation water is expensive or scarce

Applications of Object Detection in Industrial Contexts Based on Logistics Robots

The aim of this doctoral thesis is to automate the logistic flow of material under industrial conditions. For this purpose, the running processes as well as their characteristic features are first analyzed. Based on this, requirements are derived for the robots to be created and technical solutions are sought. This development of the solution is divided into the five sub-areas: Decision, Perception, Action, Interaction and Safety. Depending on the overall task to be examined, three robot concepts are created for this purpose. One for depalletising in incoming goods, one for automating provisioning on the assembly line and one for palletising in empty goods sorting. Since the logistic processes - in contrast to the production processes in already automated production areas - are mainly characterized by a high variance, dynamic changes and challenging influencing variables from the industrial environment, a very powerful perception module is necessary for the successful use of the robots. This is made up of five modules for all three robots. Depending on the function, a decision is made between function and robustness modules. The former include Detection-, Selection- and Localization-Modules. Initially, all objects are detected by Neural Networks. Then the relevant object for the process execution is selected from the set of detected objects and its gripping point is determined. In order to increase the robustness to values suitable for industrial use, these three modules are supplemented by the Aggregation- and Validation modules. In the Validation-Module, the recognized classes are examined on the basis of predefined rules for their plausibility in occurrence itself as well as in appearance among each other. Finally, this process is executed several times. The results are evaluated in the Aggregation-Module. This means that outliers, for example, caused by background processes in the plant, can be excluded. Finally, the designed robots are evaluated. Depending on the respective hardware status, this was done in series production in the factory, in test trials in the factory as well as in test trials on the development areas. The industrial suitability of the developed solution can be demonstrated by this holistic test.Ziel dieser Dissertation ist es, den logistischen Materialfluss unter industriellen Bedin- gungen zu automatisieren. Zu diesem Zweck werden zunächst die laufenden Prozesse sowie deren charakteristische Merkmale analysiert. Daraus werden Anforderungen an die zu erstellenden Roboter abgeleitet und technische Lösungen erarbeitet. Diese Entwicklung der Lösung gliedert sich in die fünf Teilbereiche: Entscheidungsfindung, Wahrnehmung, Ausführung, Interaktion und Sicherheit. Abhängig von der zu unter- suchenden Gesamtaufgabe werden zu diesem Zweck drei Roboterkonzepte erstellt. Eines für die Depalettierung im Wareneingang, eines für die Automatisierung der Bere- itstellung am Montageband und eines für die Palettierung in der Leergutsortierung. Da sich die logistischen Prozesse - im Gegensatz zu den Produktionsprozessen in bere- its automatisierten Produktionsbereichen - vor allem durch eine hohe Varianz, dy- namische Veränderungen und anspruchsvolle Einflussgrößen aus dem industriellen Umfeld auszeichnen, ist für den erfolgreichen Einsatz der Roboter ein sehr leistungs- fähiger Wahrnehmungsalgorithmus erforderlich. Dieser besteht roboterübergreifend aus fünf Modulen. Je nach Funktion wird zwischen Funktions- und Robustheitsmodulen entschieden. Erstere beinhalten die Module zur Erkennung, Auswahl und Lokalisierung. Zunächst werden alle Objekte von Neuronalen Netzen erkannt. Anschließend wird aus der Menge der erfassten Objekte das für die Prozessausführung relevante Objekt ausgewählt und die Greifpunkte bestimmt. Um die Robustheit mit Blick auf Industri- etauglichkeit zu erhöhen, werden diese drei Module durch die Module Aggregation und Validierung ergänzt. Im Modul Validierung werden die erkannten Klassen nach vordefinierten Regeln auf ihre Plausibilität sowohl im Auftreten selbst als auch im Erscheinungsbild untereinander untersucht. Schließlich wird dieser Prozess iterativ aus- geführt. Diese Ergebnisse werden im Aggregationsmodul ausgewertet. Dadurch können Ausreißer, z.B. durch Hintergrundprozesse im Werk oder verrauschte Sensorinputdaten, ausgeschlossen werden. Abschließend wird der Wahrnehmungsalgorithmus sowie die konzeptionierten Roboter evaluiert. Dies erfolgt in Abhängigkeit des Hardware-Status in der Serienproduktion im Werk, in Testversuchen im Werk sowie in Testversuchen auf den Entwicklungsbereichen. Die industrielle Eignung der entwickelten Lösung konnte durch diesen ganzheitlichen Test nachgewiesen werden

Affine recourse for the robust network design problem: between static and dynamic routing

Affinely-Adjustable Robust Counterparts are used to provide tractable alternatives to (two-stage) robust programs with arbitrary recourse. We apply them to robust network design with polyhedral demand uncertainty, introducing the affine routing principle. We compare the affine routing to the well-studied static and dynamic routing schemes for robust network design. It is shown that affine routing can be seen as a generalization of the widely used static routing still being tractable and providing cheaper solutions. We investigate properties on the demand polytope under which affine routings reduce to static routings and also develop conditions on the uncertainty set leading to dynamic routings being affine. We show however that affine routings suffer from the drawback that (even strongly) dominated demand vectors are not necessarily supported by affine solutions. © 2011 Springer-Verlag.SCOPUS: cp.kinfo:eu-repo/semantics/publishe

L'influence de l'homme sur l'érosion : 1. A l'échelle du versant

Les sols sableux recouvrent des surfaces immenses dans les zones tropicales sèches et semi-humides. En dépit de leur faible fertilité, ces sols sont de plus en plus cultivés, notamment dans les régions les plus pauvres de la planète où la pression démographique s'est accrue. A l'occasion de recherches menées au nord-est de la Thaïlande sur les propriétés physiques de ces sols, une équipe franco-thaïlandaise a récemment étudié une nouvelle technique d'amélioration, le rainurage. Contrairement à des méthodes plus classiques, cette technique apparaît, au regard des résultats obtenus, comme une option efficace pour améliorer l'état physique et la productivité des sols sableux. Le rainurage permet notamment un meilleur enracinement qui favorise la croissance de la plante. (Résumé d'auteur