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Found 25 results.

Identification of groundwater nitrogen point source contribution through combined distribute temperature sensing and in-situ UV photometry

Agriculture is the major contributor of nitrogen to ecosystems, both by organic and inorganic fertilizers. Percolation of nitrate to groundwater and further transport to surface waters is assumed to be one of the major pathways in the fate of this nitrogen. The quantification of groundwater and associated nitrate flux to streams is still challenging. In particular because we lack understanding of the spatial distribution and temporal variability of groundwater and associated NO3- fluxes. In this preliminary study we will focus on the identification and quantification of groundwater and associated nitrate fluxes by combining high resolution distributed fiber-optic temperature sensing (DTS) with in situ UV photometry (ProPS). DTS is a new technique that is capable to measure temperature over distances of km with a spatial resolution of ca1 m and an accuracy of 0.01 K. It has been applied successfully to identify and quantify sources of groundwater discharge to streams. ProPS is a submersible UV process photometer, which uses high precision spectral analyses to provide single substance concentrations, in our case NO3-, at minute intervals and a detection limit of less than 0.05 mg l-1 (ca.0.01 mg NO3--Nl-1). We will conduct field experiments using artificial point sources of lateral inflow to test DTS and ProPS based quantification approaches and estimate their uncertainty. The selected study area is the Schwingbach catchment in Hessen, Germany, which has a good monitoring infrastructure. Preliminary research on hydrological fluxes and field observations indicate that the catchment favors the intended study.

Diffusion and advection with sorption of anions, cations and non-polar molecules in organo-clays at varying thermo-chemical conditions - validation by analytical methods and molecular simulation

The sorption of anions in geotechnical multibarrier systems of planned high level waste repositories (HLWR) and of non-ionic and organic pollutants in conventional waste disposals are in the center of recent research. In aquatic systems, persistent radionuclides such as 79Se, 99Tc, 129I exist in a form of anions. There is strongly increasing need to find materials with high sorption capacities for such pollutants. Specific requirements on barrier materials are long-term stability of adsorbent under various conditions such as T > 100 C, varying hydrostatic pressure, and the presence of competing ions. Organo-clays are capable to sorb high amounts of cations, anions and non-polar molecules simultaneously having selectivity for certain ions. This project is proposed to improve the understanding of sorption and desorption processes in organo-clays. Additionally, the modification of material properties under varying chemical and thermal conditions will be determined by performing diffusion and advection experiments. Changes by sorption and diffusion will be analyzed by determining surface charge and contact angles. Molecular simulations on models of organo-clays will be conducted in an accord with experiments with aim to understand and analyze experimental results. The computational part of the project will profit from the collaboration of German partner with the group in Vienna, which has a long standing experience in a modeling of clay minerals.

AsFeP0 - A model concept for in situ investigation or arsenic and phosphate adsorption to predefined iron minerals and to characterize transformation processes of iron minerals

Shallow groundwater of the huge deltaic systems of Asia like the Red River Delta in Vietnam is often enriched in inorganic arsenic (As), threatening the health of millions of residents. The massive abstraction of groundwater in these areas locally causes an irreversible mixing of arsenic-free groundwater resources with arsenic-rich groundwater. Increased concentrations of competitive anions, especially phosphate (PO43-), decrease the immobilization capacity of the sediments. During transport, the mobility of dissolved As in local aquifers is strongly influenced by adsorption to sedimentary and ubiquitously occurring iron(oxyhydr)oxides. Additionally, arsenic-rich groundwater is often enriched in reduced iron (Fe2+) as well, which is capable to react with iron(oxyhydr)oxides, thereby inducing mineral transformations. Such transformations permanently affect the arsenic adsorption and immobilization capacity of the sediments.Within the scope of this research project, the underlying mechanisms related to As transport and the resulting threat to arsenic-free groundwater resources will be characterized in cooperation with the Swiss Federal Institute of Aquatic Science and Technology (Eawag). The research concept aims at assessing the complex interactions within the arsenic-iron-phosphate-system under field conditions at a study site next to the Red River. First, filtration experiments using local groundwater enriched in As and PO43- will be used to determine the As adsorption capacity of different and previously geochemically characterized iron(oxyhydr)oxides. In a second step, sample carrier containing As loaded iron(oxyhydr)oxides will be introduced into surface near aquifer parts of the study site (via existing groundwater monitoring wells). These samples will be exposed to local groundwater characterized by increased As, Fe2+ and PO43- concentrations for the following nine months. Using the in situ exposition of predefined iron(oxyhydr)oxides, it will be possible to distinguish potential mineral transformations and their influences on the As immobilization capacity of the respective iron(oxyhydr)oxides. By combining the results and outcomes of the field experiments, new and important conclusions regarding the mobility of As can be drawn. The data can be used to create a hydrochemical transport model describing reactive As transport within the investigation area. In addition, the results of the in situ exposition experiments will allow to draw conclusions in respective to the long term As immobilization capacity of different iron(oxyhydr)oxides, which is an essential information regarding in situ decontamination techniques.

Modellkopplung und komplexe Strukturen, Model coupling and complex structures - Evaporation-driven transport and precipitation of salts in porous media

Degradation of the soil productivity due to salt accumulation (salinization) is a major concern in arid, semi-arid and coastal regions. Soil salinization is an old issue but encouraged irrigation practices have been rapidly increasing its intensity and magnitude in the past few decades. Studies have shown that excess of the irrigated water contributes significantly to evaporation from the bare soil surface and therefore to the salinization. In some parts of the world soil salinity has grown so acute that the agricultural lands have been abandoned. Evaporation salinization is mainly influenced by interaction between the flow and transport processes in the atmosphere and the porous-medium. On the atmosphere side, wind velocity, air temperature and radiation have a strong impact on evaporation. Furthermore, turbulence causes air mixing, influences the vapor transport and creates a boundary layer at the soil-atmosphere interface which indeed influences evaporation. On the porous-medium side, dissolved salt is transported under the influence of viscous forces, capillary forces, gravitational forces and advective and diffusive fluxes. The water either directly evaporates from the water-filled pores or it is transported to air due to diffusive processes. Continuous evaporation promotes salt accumulation and precipitation resulting in soil salinization. In the scope of this work we attempt to develop a model concept capable of handling flow, transport and precipitation processes related to evaporative salinization of an unsaturated porous-medium.

Evolution of plant morphological diversity in plant-insect mutualisms

Most plants rely on insects for their pollination, protection (e.g., from herbivores) and/or seed dispersal, and have formed a mutually beneficial interaction, or mutualism. The current research investigates the evolution of plant traits involved in plant-insect mutualisms. In particular, it focuses on the evolution of extrafloral nectaries (EFNs): secretory structures on plant parts outside the flower, which offer carbohydrate-rich, water-based secretions (=nectar) to ants in return for their protection from herbivores (i.e. protective mutualisms). EFNs occur in some ferns and over hundred families of flowering plants, especially the legume family. However, their phylogenetic distribution within families, morphological diversity and evolution, and evolutionary role are poorly understood. Also EFN plant-ant interactions are known to shape entire tropical and savannah-like ecosystems, but their unexpected occurrence in deserts - where plants need to manage water carefully - has been studied only in a few cacti. This study investigated the diversity and evolution of EFNs at three different levels: (1) in the Leguminosae, the third largest and second economically most important angiosperm family, which also dominates many kinds of vegetation worldwide; (2) in the legume genus Senna, a case study where EFNs represent a key innovation (see past SNF project by B. Marazzi); and (3) in Sonoran Desert plants. Current results show that EFNs occur in species of over 130 legume genera (over twice as many as in the last published account of EFNs in this family). They are particularly abundant in the subfamily Mimosoideae, and may have evolved independently at least 30 times in the family. This incredible number of origins suggests the action of some evolutionary (perhaps genetic) precursor that allowed some clades to evolve EFNs more 'easily' given ceartin selective regimes. Most legume EFNs occur on the (typically pinnate) leaves, less often on stipules and different parts of inflorescences. In Senna, ancestral leaf EFNs appear to have evolved first between the proximal pair of leaflets only (some 40 Million years ago), and later also between the other pairs of leaflets (several times) or only at the base of the leaf stalk (once). In the Sonoran Desert area (including also mountain habitats), EFNs may occur in species from up to 32 families, in several cacti and in particular Leguminosae, dominant in this vegetation. EFNs have apparently been reduced but have been retained in a functional state (i.e., secreting nectar) in most desert legumes, and are thus capable of participating in protective mutualisms with desert ants. This research shows that EFNs are more widespread in plants than previously thought, suggesting that we may have underestimated the role of protective ant-plant interactions in shaping ecosystem ecology and evolution

Fuel cell power trains and clustering in heavy-duty transports (FELICITAS)

Objective: The FELICITAS consortium proposes an Integrated Project to develop fuel cell (FC) drive trains fuelled with both hydrocarbons and hydrogen. The proposed development work focuses on producing FC systems capable of meeting the exacting demands of heavy-dut y transport for road, rail and marine applications. These systems will be: - Highly efficient, above 60Prozent - Power dense, - Powerful units of 200kW plus, - Durable, robust and reliable. Two of the FC technologies most suitable for heavy-duty transport applic ations are Polymer Electrolyte FuelCells (PEFC) and Solid Oxide Fuel Cells (SOFC). Currently neither technology is capable of meeting the wideranging needs of heavy-duty transport either because of low efficiencies, PEFC, or poor transient performance,SO FC. FELICITAS proposes the development of high power Fuel Cell Clusters (FCC) that group FC systems with other technologies, including batteries, thermal energy and energy recuperation.The FELICITAS consortium will first undertake the definition of the requirements on FC power trains for the different heavy-duty transport modes. This will lead to the development of FC power train concepts, which through the use of advanced multiple simulations, will undertake evaluations of technical parameters, reliab ility and life cycle costs. Alongside the development of appropriate FC power trains the consortium will undertake fundamental research to adapt and improve existing FC and other technologies, including gas turbines, diesel reforming and sensor systems f or their successful deployment in the demanding heavy-duty transport modes. This research work will combine with the FC power trains design and simulation work to provide improved components and systems, together with prototypes and field testing where ap propriate.The FELICITAS consortium approach will substantially improve European FC and associated technology knowledae and know-how in the field of heavv-duty transport.

Natural product lead discovery at the microgram scale - an integrated approach

Natural products remain an important source for drugs and a source of inspiration for medicinal chemists for the design of synthetic drugs and probes for the study of biological functions. The contribution of academic laboratories in natural products discovery has been substantial. The limiting factor of pharmaceutical natural product research has been with the tedious process of purification and identification of the lead molecules from the highly complex crude extract. Recent technological advances enable now a miniaturization of the screening and discovery process for natural product leads. The proposal here is for the purchase of a 500 MHz NMR spectrometer specifically equipped for the measurement of mass limited samples. It includes a recently commercialized 1 mm probe and autosampler and is capable of recording 1D and 2D NMR spectra with microgram (20-100 myg) amounts of natural products and synthetic drug-like molecules. The spectrometer is configured to fit into the technology platforms and the workflows of the Drug Screening Group of the Swiss Tropical Institute and the Institute of Pharmaceutical Biology. The instrument shall be used for various interdisciplinary projects of the two principal applicants and for a consortium which is being established. The major use will be for HPLC-based lead discovery in the area of Alzheimer's disease, Malaria, and neglected tropical diseases. The instrument will also be employed for metabolic fingerprinting of selected plants and phytomedicines. A third application will be in the analysis of compound libraries from external sources which are screened by the applicants in the context of the principal projects. An NMR instrument with this configuration is currently not in operation at a Swiss university. It is the missing link in a technology platform established at the laboratories of the two applicants. This platform should enable a paradigm shift in the way how natural product leads are identified, namely by miniaturizing the entire process of screening, separation and lead identification to the microgram level. A significant gain in efficiency of the discovery process and, thus, in research productivity, both qualitative and quantitative, is anticipated. The equipment will also be of interest to all those scientists in the biomedical sciences who need structural information from mass limited samples such as, for example drug metabolites.

DEVOTES: Innovative Tools for Understanding and Assessing Good Environmental Status (GES) of Marine Waters ('The Ocean for Tomorrow')

The objectives are to: (i) improve our understanding of human activities impacts (cumulative, synergistic, antagonistic) and variations due to climate change on marine biodiversity, using long-term series (pelagic and benthic). This objective will identify the barriers and bottlenecks (socio-economic and legislative) that prevent the GES being achieved (ii) test the indicators proposed by the EC, and develop new ones for assessment at species, habitats and ecosystems level, for the status classification of marine waters, integrating the indicators into a unified assessment of the biodiversity and the cost-effective implementation of the indicators (i.e. by defining monitoring and assessment strategies). This objective will allow for the adaptive management including (a) strategies & measures, (b) the role of industry and relevant stakeholders (including non-EU countries), and (c) provide an economic assessment of the consequences of the management practices proposed. It will build on the extensive work carried out by the Regional Seas Conventions (RSC) and Water Framework Directive, in which most of the partners have been involved (iii) develop/test/validate innovative integrative modelling tools to further strengthen our understanding of ecosystem and biodiversity changes (space & time); such tools can be used by statutory bodies, SMEs and marine research institutes to monitor biodiversity, applying both empirical and automatic data acquisition. This objective will demonstrate the utility of innovative monitoring systems capable of efficiently providing data on a range of parameters (including those from non-EU countries), used as indicators of GES, and for the integration of the information into a unique assessment The consortium has 23 partners, including 4 SMEs (close to 17Prozent of the requested budget) and 2 non-EU partners (Ukraine & Saudi Arabia). Moreover, an Advisory Board (RSC & scientific international scientists) has been designed,to ensure a good relationship with stakeholders.

Storage of hydrogen in hydrides

Hydrogen is the ideal synthetic fuel to convert chemical energy into electrical energy or into motive power because it is light weight, highly abundant and its oxidation product is vapor of water. Thus its usage helps to reduce the greenhouse gases and it conserves fossile resources. There is even a clean way to produce hydrogen by electrolysis of water by means of photo voltaics (SvW06, VSM05, PMM05). There are various possibilities to store the hydrogen for later use: Liquid and gaseous hydrogen can be stored in a pressure vessel, hydrogen can be adsorped on large surface areas of solids, and finally crystal lattices of metals or other compounds can be used as the storage system, where hydrogen is dissolved either on interstitial or on regular lattice sites by substitution (SvW06, San99). The latter process and its reversal is called hydriding respectively dehydriding. The subject of this proposal is the modeling and simulation of that process. The main problem of a rechargeable lithium-ion battery is likewise a storage problem, because in a rechargeable battery, both the anode and cathode do not directly take part in the electrochemical process that converts chemical energy into electrical energy, rather they act as host systems for the electron spending element, which is here lithium (Li). During the last month the applicant developed and exploited a mathematical model that is capable to capture the storage problem of an iron phosphate (FePO4) cathode, where the Li atoms are stored on interstitial lattice sites (DGJ07).

Universal microarrays for the evaluation of fresh-water quality based on detection of pathogens and their toxins

Monitoring the quality of drinking water is of paramount importance for public health. 'Water is not a commercial product but a heritage that must be protected, defended and treated as such' (Water Framework Directive 2000/60/EC). The threat of waterborne diseases in Europe will predictably increase in the future as the human population increases and as a result of globalization and migration from non-EU countries and of climate change. Development of efficient, sensitive, robust, rapid and inexpensive tests to monitor various aspects of water quality represents an essential milestone within the strategy for control and prevention of diseases caused by waterborne pathogens and by algal toxins. Traditional methods for the detection of waterborne pathogens, based on cultivation, biochemical characterisation and microscopic detection are laborious and time-consuming; molecular biological tools have now greatly enhanced our ability to investigate biodiversity by identifying species and to estimate gene flow and distribution of species in time and space. My AQUA aims to design and develop a universal microarray chip for the high-throughput detection in water of known and emerging pathogens (bacteria, viruses, protozoa and cyanobacteria) and to assess the water quality monitoring the presence of select bioindicators (i.e. diatoms). A chip able to detect cyanobacterial toxins will also be developed. These innovative molecular tools should be amenable to automation so that they could be deployed on moorings for routine semi-continuous monitoring of water quality. My AQUA also aims to identify cyanophages potentially capable of controlling and mitigating the periodical blooming of toxic cyanobacteria in drinking water reservoirs. Overall, these innovative and cost efficient technologies will reduce energy requirements and improve performance of water treatment, and allow rapid management response to new situations brought about by environmental (including climatic) changes.

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