Das Projekt "The role of turgor in rain-cracking of sweet cherry fruit" wird vom Umweltbundesamt gefördert und von Leibniz Universität Hannover, Institut für Biologische Produktionssysteme, Fachgebiet Obstbau durchgeführt. Rain-cracking limits the production of many soft and fleshy fruit including sweet cherries world wide. Cracking is thought to result from increased water uptake through surface and pedicel. Water uptake increases fruit volume, and hence, turgor of cells (Pcell) and the pressure inside the fruit (Pfruit) and subjects the skin to tangential stress and hence, strain. When the strain exceeds the limits of extensibility the fruit cracks. This hypothesis is referred to as the Pfruit driven strain cracking. Based on this hypothesis cracking is related to two independent groups of factors: (1) water transport characteristics and (2) the intrinsic cracking susceptibility of the fruit defined as the amount of cracking per unit water uptake. The intrinsic cracking susceptibility thus reflects the mechanical constitution of the fruit. Most studies focussed on water transport through the fruit surface (factors 1), but only little information is available on the mechanical constitution (i.e., Pfruit and Pcell, tensile properties such as fracture strain, fracture pressure and modulus of elasticity of the exocarp; factors 2). The few published estimates of Pfruit in sweet cherry are all obtained indirectly (calculated from fruit water potential and osmotic potentials of juice extracts) and unrealistically high. They exceed those measured by pressure probe techniques in mature grape berry by several orders of magnitude. The objective of the proposed project is to test the hypothesis of the Pfruit driven strain cracking. Initially we will focus on establishing systems of widely differing intrinsic cracking susceptibility by varying species (sweet and sour cherry, Ribes and Vaccinium berries, plum, tomato), genotype (within sweet cherry), stage of development and temperature. These systems will then be used for testing the hypothesis of Pfruit driven strain cracking. We will quantify Pfruit und Pcell by pressure probe techniques and compression tests and the mechanical properties of the exocarp using biaxial tensile tests. When the presence of high Pfruit and Pcell is confirmed by direct measurements, subsequent studies will focus on the mode of failure of the exocarp (fracture along vs. across cell walls) and the relationship between failure thresholds and morphometric characteristics of the exocarp. However, when Pfruit und Pcell are low, the hypothesis of Pfruit driven strain cracking must be rejected and the mechanistic basis for low pressures (presence of apoplastic solutes) clarified on a temporal (in the course of development) and a spatial scale (exocarp vs. mesocarp). We focus on sweet cherry, because detailed information on this species and experience in extending the short harvest period is available. Where appropriate, other cracking susceptible species (sour cherry, plum, Vaccinium, Ribes, tomato) will be included to further extend the experimental period and to maximize the range in intrinsic cracking susceptibility.
Das Projekt "E 3: Market potential of high-value agricultural products as a determinant for rural development in Northern Thailand and Vietnam" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Agrar- und Sozialökonomie in den Tropen und Subtropen durchgeführt. The objective of this project is to evaluate markets and marketing systems relevant for assessing the potential of specific agricultural products in the rapidly changing rural environment of northern Thailand and Vietnam. The project aims (1) to evaluate the market potential of high value fruit products (mango, lychee, longan which are the subject of research in subproject D1), (2) to assess the feasibility and economies of scale of fruit processing (as technically required following research in subproject E1 and E2), and (3) to reveal the market effects of alternative production techniques (improved animal production in D2, farming systems in D3) introduced into agricultural production systems. This will provide information for the technical and farming systems projects on adjustment needs with respect to market prices and costs. Market information is indispensable for the products mentioned above, as many of them are supposed to be products with high income elasticities and therefore strongly dependent on macroeconomic developments such as recent market and income distortions observed in Southeast Asia. Research in this phase will lay the groundwork for assessing the optimal structure (location, size, number) of a processing industry in the later phases of the SFB.
Das Projekt "European Research Project for Optimised Ballasted Tracks (EUROBALT)" wird vom Umweltbundesamt gefördert und von MAN Technologie AG, System Electronics durchgeführt. Achievements:The EUROBALT project has led to the advancement of knowledge in the behaviour of ballasted track in several different areas. The measurements have shown the importance of the track stiffness in the whole process of the track degradation. Even though a complete understanding has not been achieved in this particular area, this concept will be now considered by the railways companies. Different tools have also been improved or developed in order to measure the track stiffness, under traffic or by separate investigation (STEDEF measurement technique or PANDROL double integration). Modelling the ballast has been investigated with first studies with new approaches (ENPC). Moreover, two models have been developed, with the same goal of predicting track geometry deterioration. Even though the validation has been limited, it is a big step forward in the study of the phenomena (INRETS 'VOCO + BALTAS' and TUB SIRaGe). As for the models of track damage modelling, different problems were studied and models were developed or improved. These models will also allow a better understanding of the phenomena of track deterioration and the prediction of maintenance and renewal requirement and costs (BRR models). The monitoring studies led to : the development of a prototype able to recover in real time the long wave faults on a track, using versine based measurement cars (MAN technique), the development of a calculation method to define the forces applied on a track section when a train passes, using the data obtained from the new piezofoil sensors developed within the project (MAN method and TUB piezofoil sensors applications). What is also important is the knowledge gained by the different participants, particularly the railways companies. The different approaches used to characterise the behaviour of the ballast showed that the parameters are numerous and not easy to resolve. It can be stated, however, that the concepts of track elasticity or track elasticity variation is one of the key factors in track geometry deterioration. Further studies must be led now to describe more precisely its importance, define means of measurement, and develop the track specifications necessary to realise the benefits that are possible. The EUROBALT project is a big step forward in providing a more precise knowledge of the ballasted track. A complete understanding, however, remains elusive, and is likely to require significant further investigations. . Prime Contractor: Societe Nationale des Chemins de Fer Francais (SNCF); Paris; France.
Das Projekt "Festigkeits- und Fliessverhalten von Steinsalzproben aus Salzstoecken" wird vom Umweltbundesamt gefördert und von Technische Universität Clausthal, Institut für Metallkunde und Metallphysik durchgeführt. Die Endlagerung radioaktiver Abfaelle in Salzstoecken wird zur Zeit experimentell erprobt. Dabei spielt die Langzeitstabilitaet von Hohlraeumen im Salz unter Einwirkung des Gebirgsdruckes, eventuell bei erhoehter Temperatur im Falle von Hochaktiven Abfaellen, eine wichtige Rolle. Das plastische Fliessen eines einzelnen Salzkristalls haengt von der kristallographischen Orientierung ab. Das Fliessverhalten eines Salzstockes haengt daher von der Orientierungsverteilung oder Textur ab. Es gibt daher in den letzten Jahren eine Reihe von Bemuehungen, Texturen von Salzstoecken zu messen und mit dem Fliessverhalten zu korrelieren. Das wird durch die Grobkoernigkeit der natuerlichen Salze erschwert. Die Arbeiten gehen daher in zwei Richtungen: 1) Entwicklung wirtschaftlicher Messverfahren zur routinemaessigen Texturbestimmung in grobkoernigen Salzen durch Neutronenbeugung, durch grossflaechige Integration beim Roentgenverfahren, durch akustische Messungen. 2) Modelluntersuchungen der Textur und des Fliessverhaltens feinkoerniger synthetischer Salzproben.
Das Projekt "Eco-evolutionary responses and feedbacks of a key herbivore to lake oligotrophication" wird vom Umweltbundesamt gefördert und von Universität Konstanz, Limnologisches Institut durchgeführt. The project will use analysis of long-term data, resurrection ecology and modeling to investigate the ecological and evolutionary response of an aquatic key herbivore, Daphnia, to environmental change. In addition, the results obtained will enable to estimate the consequences of the evolutionary response of Daphnia for its population dynamics, persistence and consequently, overall ecosystem dynamics. The project will analyze in detail the response of Daphnia, its food, competitors and predators to oligo-trophication in a model ecosystem, i.e., Lake Constance and additionally variability in Daphnia population dynamics in several of the best studied lakes of the world. Historical field samples from Lake Constance will be re-analyzed to study the phenotypic life history and morphological responses of Daphnia to oligo-trophication. Using resurrection ecology we will analyze the evolutionary response of Daphnia galeata life history parameters to oligo-trophication - with special emphasis on its investment into sexual reproduction/production of resting eggs as well as life history plasticity in response to invertebrate predators and declining food levels. These analyses (in combination with model simulations) will provide key data for understanding the role of Daphnia life cycle strategy (overwintering in the plankton or in resting eggs) for Daphnia persistence in permanent lakes, for the interpretation of Daphnia resting egg banks, and the evolution of the genetic variances and co-variances of life history parameters.
Das Projekt "Adaptation of forest trees to climatic change - climate sensitive growth dynamics of Douglas-fir provenances" wird vom Umweltbundesamt gefördert und von Forstliche Versuchs- und Forschungsanstalt Baden-Württemberg durchgeführt. Dieser von der FVA-Abt. Waldwachstum zusammen mit den Institut für Waldwachstum (Uni Freiburg) und dem Lehrgebiet Waldbau (Hochschule Forstwirtschaft, Rottenburg) gestellte Antrag ist Teil eines Projektpaketes mit fünf unterschiedlichen Anträgen (davon 3 getrennte Anträge der FVA), für das die Federführung bei der FVA-Abt. Waldökologie liegt. Die von der Abt. Waldwachstum zur Finanzierung beantragten Arbeitspakete umfassen zwei getrennten Bereiche: 1) Bereitstellung des gemeinsam verwendeten Versuchsmaterials: Ein für den gesamten Projektverbund entscheidender Beitrag liegt darin, dass im Rahmen dieses Projektes aus etablierten Douglasien-Provenienzversuchen Versuchsbestände und Untersuchungsmaterial (z.B. Bäume) als gemeinsame Basis für die Forschungsarbeiten aller beteiligter Projektpartner bereitgestellt werden. 2) Waldwachstumskundliche Analyse i.e.S. mit folgenden Hauptzielen: Die Analyse der jährlichen Wuchsdynamik als Reaktion auf Klima- und Witterungsereignisse und die Entwicklung eines genotyp- und klimasensitiven Wuchsmodells (FVA-WW). Die retrospektive Untersuchung des jährlichen Wachstums bezieht sich auf die langfristige Analyse von Wachstumstrends und die Frage, in welchem Ausmaß genotypische Merkmale mit Wachstumsreaktionen auf Witterungsfaktoren korrespondieren. Die Auswirkungen auf das Wachstum werden in kurz-, mittel- und langfristige Auswirkungen differenziert. Die Ergebnisse sollen in einen bestehenden Wachstumssimulator implementiert werden, um genotypspezifische Wuchsdynamiken zu berücksichtigen und unterschiedliche Klimasensitivität bei Wachstumsprognosen berücksichtigen zu können.
Das Projekt "Statische Berechnung von Rohrleitungen in Sickerwasserentsorgungssystemen bei Abfalldeponien" wird vom Umweltbundesamt gefördert und von Landesgewerbeanstalt Bayern durchgeführt. Im Rahmen der erstellten Grundsatzuntersuchung wurden ueber 4 verschiedene Rechenmodelle statische Berechnungen zur Belastungsfaehigkeit von Deponiedraenrohren aus unterschiedlichen Materialien (PE-HD, PVC, Asbestzement, Steinzeug) angestellt. In den rechnerischen Parameteransaetzen wurden jeweils die Einflussgroessen (a) Hoehe der Abfallueberschuettung und (b) elastische Bettung (=Auflagerart: Ton bzw Sand-Bentonit-Mischung) variiert. Fuer die Muelldichte wurde den Modellrechnungen ein Wert von 11-15 kN/m3 zugrundegelegt. Bei verschiedenen Belastungsstufen wurden sowohl Bodenkennwerte (Elastizitaets-, Steife- und Verformungsmodul) der jeweiligen Auflagerart als auch die materialabhaengigen, auf die Rohrleitungen wirkenden Spannungen ermittelt und tabellarisch gegenuebergestellt.
Das Projekt "Charakterisierung mikrostruktureller Gesteinseigenschaften auf Grundlage der komplexen elektrischen Leitfaehigkeit sowie komplexer elastodynamischer Parameter" wird vom Umweltbundesamt gefördert und von Technische Universität Clausthal, Institut für Geophysik durchgeführt. Dieses Projekt, das in Kooperation zwischen dem Institut fuer Geophysik der TU Clausthal und dem Wissenschaftsbereich Angewandte Geophysik der BA Freiberg durchgefuehrt wurde, diente der anwendungsorientierten Grundlagenforschung zur Untersuchung des Zusammenhangs zwischen der inneren Gesteinsmikrostruktur und dynamischen physikalischen Groessen, insbesondere der komplexen elektrischen Leitfaehigkeit von 1 mHz bis 1 MHz und elastodynamischer Eigenschaften, um die Moeglichkeiten und Grenzen der Aussagekraft geophysikalischer Gelaende- und Bohrlochmessverfahren zur Gewinnung von Information ueber Lagerstaetten, hydrogeologische und umweltschutztechnische Fragestellungen zu gewinnen. Hierzu wurden Verfahren zur Charakterisierung der Mikrostruktur und zur Messung der komplexen dynamischer Parameter im Labor entwickelt. Ergebnisse sind experimentell begruendete fraktale Modelle fuer den Einfluss der Mikrostruktur auf die dynamischen Parameter, die zur Ermittlung lagerstaettentechnischer, hydrogeologischer und umweltschutztechnischer Kennwerte aus geophysikalischen Messwerten herangezogen werden koennen.
Das Projekt "Phenotypic divergence in widespread plants : genetic drift, selection and plasticity" wird vom Umweltbundesamt gefördert und von Universität Basel, Philosophisch-Naturwissenschaftliche Fakultät durchgeführt. This thesis presents studies that describe and explain phenotypic differentiation within several alpine plant species. The key elements that are addressed are threefold: (1) effects of neutral genetic drift, natural selection and phenotypic plasticity on phenotypic differentiation; (2) effects of glacial history, geography and climate on phenotypic differentiation and adaptation; (3) genetic structure and gene flow at small spatial scale. Combining all three elements, the aim of this thesis is to understand how a plant species' evolution towards its current state is affected at different spatial scales by neutral genetic drift and historical (i.e. glaciation-related) as well as more recent (i.e. postglacial) environmental influences. To measure phenotypic differentiation in important plant traits, common garden experiments were performed with several alpine plant species (Campanula thyrsoides, C. barbata, Geum reptans) sampled from populations across the European Alps and Jura Mountains. Phenotypic differentiation was generally mirrored by molecular differentiation into distinct phylogeographic groups, which is explained by long-term survival in isolated glacial refugia. The results therefore suggest that glacial history affected not only the species' neutral genetic structure but also its phenotype. For some traits and in some regions, such differentiation could be explained as adaptation to the regional environment. For instance, the distinct phenology in Campanula thyrsoides, showing delayed flowering in the submediterranean southeastern Alps contrasting with early flowering at higher elevation in the other regions to the west, is clearly an adaptation to season length in the respective environments. Differentiation in various other traits could not be explained as adaptations and may therefore be due to drift alone. Postglacial adaptation was detected when correlating trait values with altitude of origin. For instance, the negative correlation of altitude with plant height in Campanula thyrsoides, achieved without compromising flower production, is probably an adaptation to harsher conditions and to increased investment in roots. Adaptation can also occur through phenotypic plasticity. In an experiment in which Campanula thyrsoides was grown in common gardens at three different altitudes, variability in the functional trait of specific leaf area could be dissected into a constitutive genetic part and a phenotypic plastic part.
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