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Bucher A.,Fakultat Maschinen und Energietechnik | Gorke U.-J.,Helmholtz Zentrum fur Umweltforschung | Kreiig R.,TU Chemnitz
Lecture Notes in Applied and Computational Mechanics

This contribution presents advanced numerical models for the solution of the direct and inverse problems of nearly incompressible hyperelastic processes at large strains. The discussed mixed finite element approach contributes to the numerical simulation of coupled multiphysics problems, including the calibration of appropriate material models (parameter identification). The presented constitutive approach is based on the multiplicative decomposition of the deformation gradient resulting in a two-field formulation with displacement components and hydrostatic pressure as primary variables. The ill-posed inverse problem of parameter identification analyzing inhomogeneous displacement fields is solved using deterministic trust-region optimization techniques.Within this context, a semi-analytical approach for sensitivity analysis represents an efficient and accurate method to determine the gradient of the objective function. Themixed boundary value problem is based on the spatial discretization of the weak formulations of the linear momentum balance and the incompressibility condition. Its linearization serves as basis for the solution of the direct problem, while the implicit differentiation of the weak formulations with respect to material parameters provides the necessary relations for the semi-analytical sensitivity analysis. Adaptive mesh refinement and mesh coarsening are realized controlled by a residual a posteriori error estimator. Efficiency and accuracy of the presented direct and inverse numerical techniques are demonstrated on a typical example. © 2013 Springer-Verlag Berlin Heidelberg. Source

Renner S.C.,University of Ulm | Heynen I.,Naumann Museum | Neumann D.,Zoologische Staatssammlung Munich | Feit U.,Bundesamt fur Naturschutz | And 6 more authors.

Biodiversity' is increasingly perceived as an important resource. Conservation, access and sustainable use of biodiversity (genetic resources, species, samples) are negotiated at political levels, resulting in an internationally binding legal framework. Understanding and awareness of export and import permits for biological samples is increasingly important for biologists to perform research projects legally and timely. Nevertheless, some biologists still export and import biological samples in disregard of or non-compliant with national and international legislation, conventions, and regulations. Resulting difficulties may not only cause serious problems during field work, but may also delay the export, import or exchange of samples. Comprehensive a priori information regarding legal requirements helps to avoid or at least diminish potential problems. We identified four major factors facilitating export/import permits: (1) good personal (mutually trusted) contacts in the country of origin, (2) understanding and compliance with all relevant laws and regulations; (3) access to information regarding knowledge on permits, regulations and laws including their circulation within the researcher communities and (4) access to consistent and up to date regulations and guidelines. We provide information on key issues to assist research teams trying to reduce problems and misunderstandings. © DO-G,IfV,MPG 2012. Source

Totsche K.U.,Friedrich - Schiller University of Jena | Rennert T.,Friedrich - Schiller University of Jena | Gerzabek M.H.,University of Vienna | Kogel-Knabner I.,TU Munich | And 3 more authors.
Journal of Plant Nutrition and Soil Science

Soil, the "Earth's thin skin" serves as the delicate interface between the biosphere, hydrosphere, atmosphere, and lithosphere. It is a dynamic and hierarchically organized system of various organic and inorganic constituents and organisms, the spatial structure of which defines a large, complex, and heterogeneous interface. Biogeochemical processes at soil interfaces are fundamental for the overall soil development, and they are the primary driving force for key ecosystem functions such as plant productivity and water quality. Ultimately, these processes control the fate and transport of contaminants and nutrients into the vadose zone and as such their biogeochemical cycling. The definite objective in biogeochemical-interface research is to gain a mechanistic understanding of the architecture of these biogeochemical interfaces in soils and of the complex interplay and interdependencies of the physical, chemical, and biological processes acting at and within these dynamic interfaces in soil. The major challenges are (1) to identify the factors controlling the architecture of biogeochemical interfaces, (2) to link the processes operative at the individual molecular and/or organism scale to the phenomena active at the aggregate scale in a mechanistic way, and (3) to explain the behavior of organic chemicals in soil within a general mechanistic framework. To put this in action, integration of soil physical, chemical, and biological disciplines is mandatory. Indispensably, it requires the adaption and development of characterization and probing techniques adapted from the neighboring fields of molecular biology, analytical and computational chemistry as well as materials and nano-sciences. To shape this field of fundamental soil research, the German Research Foundation (DFG) has granted the Priority Program "Biogeochemical Interfaces in Soil", in which 22 individual research projects are involved. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Gorsch K.,Helmholtz Zentrum fur Umweltforschung | Hoffmann P.,Helmholtz Zentrum fur Umweltforschung | Schlenker U.,BAUER Umwelt GmbH | Aurich A.,Helmholtz Zentrum fur Umweltforschung | Zehnsdorf A.,Helmholtz Zentrum fur Umweltforschung

Water sediment contaminated with heavy metals is a problem worldwide. The presented ecological conditioning and bioleaching process was demonstrated on a practical scale with the aim to improve material properties and to reduce the heavy metal content so that the sediment can be reused. The bioleaching part of the process was performed in two trials, resulting in the removal of zinc and cadmium. After the treatment the sediment was suitable to be reused for recultivation of mining dumps, while the precipitation sludge may possibly be used as a source for strategic elements. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Marquard E.,Helmholtz Center for Environmental Research | Dauber J.,Thunen Institute For Biodiversitat | Doerpinghaus A.,Bundesamt fur Naturschutz Referat Planung | Droschmeister R.,Bundesamt fur Naturschutz | And 13 more authors.
Natur und Landschaft

In the light of rapid global change and the impending loss of ecosystem services, informative data on the state and trends of biological diversity are vital. Generating these data in Germany requires modifications to and better coordination among the existing monitoring programmes. To this end, closer cooperation between scientific institutions, executing agencies and other relevant organizations is needed. The following recommendations summarize the authors' views on aspects key to reshaping the biological monitoring programmes in Germany:. Source

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