Das Projekt "Sub project: Spatial Variations of the Phaseshift between Ocean Surface Warming, Evaporation and Changes oft Continental Ice Volume at Terminations I and II (P.O.E.T)" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR) durchgeführt. The proposed study will examine the timing and phasing of the warming of the ocean surface during the beginning of interglacial Marine Isotope Stages (MIS) 1 and 5. The primary goal is to verify the hypothesis whether the tropical ocean or the Northern North Atlantic is pacing climate change at the glacial/interglacial transitions. The change in sea-surface temperature (SST) in relation to sea-surface salinity (SSS) and global ice volume change will be deciphered by using a hitherto unique approach, namely the measurement of combined ?44/40Ca, Mg/Ca and ?18O in the same planktonic foraminiferal species in comparison to alkenone-based temperatures. The high-resolution multi-proxy data series will be gathered from tropical to high northern latitude ocean areas in the Atlantic Ocean, roughly following the pathway of ocean heat and moisture via the Gulf Stream system, and hence, covering areas with different evaporation/precipitation ratios. We will reconstruct these oceanic parameters for the surface ocean by using shallow-dwelling and by using deep-dwellers foraminifers for the subsurface ocean.
Das Projekt "Metrology for Biofuels - Call 2009 Energy I: Providing a reference for physical parameters in biofuels" wird vom Umweltbundesamt gefördert und von Physikalisch-Technische Bundesanstalt durchgeführt. The European directive 2009/28/EC on the promotion of the use of energy from renewable sources endorsed in Article 3 a mandatory target of a 20Prozent share of energy from renewable sources in overall Community energy consumption by 2020 and a target of at least 10 percent of the final consumption of energy in transport. Fuels from renewable sources (biofuels) show differences to fossil fuels when looking to their physical parameters. Thus, the parameters known for fossil fuels and used for volume measurement (legal purpose)and for process control in the engines (industrial purpose) cannot be transferred to biofuels. The parameters density, viscosity, and calorific value are important for legal purposes (measurement of volume, conversion into a standard volume at defined temperature, measurement of energy content). The ANNEX III Energy content of transport fuels of the European directive 2009/28/EC is not supported by traceable measurements. The density and thermal expansion coefficients of biofuels differ from those of fossil fuels. The density of blends does not follow a simple linear mixing rule. In order to be able to take into account these differences, accurate measurements of density at various temperatures are required. The viscosity is a quantity used as a correction factor for some flow meters. Thus, accurate measurements of viscosity at various temperatures are required, too. The calorific value as a measure for the energy content is the most important quantity describing the amount of substance needed for energy generation and, by this, is of large importance for the economical benefit and influences the impact on environment, especially the carbon dioxide balance. The parameters density, viscosity and calorific value input to the process control during injection, atomisation, ignition, and combustion of fuel in the engine. A precise knowledge of these parameters is necessary for the optimisation of the combustion process to reach a reduction in consumption, pollutant emission, and noise. Thus the physical parameters of biofuels need to be determined by measurements traceable to the SI. At moment, singular measurements of different parameters already exist. But many of them are not traceable to SI and are not supported by a chemical analysis of the material. This prohibits a comparison of results. There are no area-wide investigations about the spread of parameters within one sort of biofuel produced at different regions of Europe and investigations about the spread of parameters between different sorts of biofuel. The measurement methods are not optimised for biofuels so far. Reference materials are available for some parameters at standard temperatures and pressures, but not for the large range of temperatures which is relevant. The large variety of biofuels and their blends with fossil fuels require rules to determine the physical parameters from the knowledge of their constituents. usw.
Das Projekt "Ein Laser-Doppler-Anemometer fuer die Messung der Windgeschwindigkeiten und sein Einsatz bei Windstromerzeugern" wird vom Umweltbundesamt gefördert und von Universität Erlangen-Nürnberg, Institut für Verfahrenstechnik, Lehrstuhl für Strömungsmechanik durchgeführt. Objective: The present report summarizes the work carried out in this project during the year 1988. The aim in this period was to complete the wind measuring system. The main work has concentrated on two points. First to finish the mounting of the optical system. Laser-Doppler anemometer for wind velocity measurements is nearly completed. The second point of interest was to refine the signal processing in order to get an effective technique for wind velocity measurements. General Information: The technique employed requires photon detection of the scattered light from small naturally available particles. Instead of the variation of an analogue voltage at the output of the photomultiplier, the Doppler frequency is coded as a changing density of photon events. The resulting pulse train is amplitude normalized and fed into a digital correlator (Malvern K7026) which yields its temporal autocorrelation function. Due to the long measurement distance the intensity of the scattered light is much smaller as compared to that of the daylight. In order to differentiate these two light sources, an option has been provided to specify a clip level. All photon counts below the clip level are then suppressed. This has the effect that the autocorrelation function is evaluated only for those time intervals in which a sufficiently large particle giving a slightly higher than average intensity crosses the measurement volume. In this manner the autocorrelation function of the pulse train is continuously accumulated in the buffer of the correlator. The contents of this buffer are periodically transmitted to a microcomputer via the fast Access/DMA port and the correlator-buffer is reset. During the time the data gets accumulated for building up a new correlogram in the correlator the evaluation of velocity for the previous set of data is carried out by the microcomputer. A built-in hardware-FFT-card performs a fast fourier transform on the data to evaluate the spectrum of the autocorrelation function, which generally has a sharp peak at the main frequency. To estimate the signal quality, a signal-to-noise-ratio (SNR) is calculated by dividing the height of the main peak by the average level of the other frequency-components. If this value exceeds a certain preassigned number, the autocorrelation function, together with the corresponding parameters like time, position of the measurement volume, velocity, overall light intensity, etc , is stored on the disk. Thereafter the computer is ready to receive the next correlogram and the whole process is repeated. The stored values of the various parameters may be used later to apply more sophisticated but time-consuming frequency evaluation methods.
Das Projekt "Bildung und Oxidation von Russ und gasfoermigen Schadstoffen im Brennraum eines DI-Dieselmotors unter dem Einfluss von Abgasrueckfuehrung" wird vom Umweltbundesamt gefördert und von Technische Hochschule Aachen, Lehrstuhl für Angewandte Thermodynamik und Institut für Thermodynamik durchgeführt. The formation and oxidation of pollutants like soot, HC, NOx and CO inside the cylinder of a DI diesel engine with Exhaust Gas Recirculation (EGR) will be studied. The formation and oxidation of pollutants influenced by external recirculated exhaust gas will be compared with the processes without EGR. Thus the part of exhaust gas components like CO2 and H2O on soot formation/oxidation and NOx formation can be studied. The spatial and temporal distribution of these components in the fuel spray as well as the soot particle size history will be observed during the combustion process by means of gas sampling technique. In contradiction to optical in-cylinder measurements, this technique allows to analyse components of an identical probe volume.
Das Projekt "Sub project: Coupling and competitiveness of iron-, sulfate-, and CO2-reduction along gradients" wird vom Umweltbundesamt gefördert und von Universität Bayreuth, Fachgruppe Geowissenschaften, Bayreuther Zentrum für Ökologie und Umweltforschung (BayCEER), Lehrstuhl für Hydrologie durchgeführt. The relevance of biogeochemical gradients for turnover of organic matter and contaminants is yet poorly understood. This study aims at the identification and quantification of the interaction of different redox processes along gradients. The interaction of iron-, and sulfate reduction and methanogenesis will be studied in controlled batch and column experiments. Factors constraining the accessibility and the energy yield from the use of these electron acceptors will be evaluated, such as passivation of iron oxides, re-oxidation of hydrogen sulfide on iron oxides. The impact of these constraints on the competitiveness of the particular process will then be described. Special focus will be put on the evolution of methanogenic conditions in systems formerly characterized by iron and sulfate reducing condition. As methanogenic conditions mostly evolve from micro-niches, methods to study the existence, evolution and stability of such micro-niches will be established. To this end, a combination of Gibb's free energy calculations, isotope fractionation and tracer measurements, and mass balances of metabolic intermediates (small pool sizes) and end products (large pool sizes) will be used. Measurements of these parameters on different scales using microelectrodes (mm scale), micro sampling devices for solutes and gases (cm scale) and mass flow balancing (column/reactor scale) will be compared to characterize unit volumes for organic matter degradation pathways and electron flow. Of particular interest will be the impact of redox active humic substances on the competitiveness of involved terminal electron accepting processes, either acting as electron shuttles or directly providing electron accepting capacity. This will be studied using fluorescence spectroscopy and parallel factor analysis (PARAFAC) of the gained spectra. We expect that the results will provide a basis for improving reactive transport models of anaerobic processes in aquifers and sediments.
Das Projekt "Lightweight in-situ tracer experiment in the stratosphere" wird vom Umweltbundesamt gefördert und von Universität Frankfurt, Institut für Meteorologie und Geophysik durchgeführt. Objective: The main objective of the project is the development of a balloon borne Lightweight In-situ Tracer Experiment in the Stratosphere (LITES) for simultaneous profile observations of ozone and the long-lived trace gases sulphur hexafluoride (SF6) and the chlorofluorocarbon CFC 12 (CF2Cl2) in the stratosphere. The LITES - package is designed to make measurements up to altitudes of about 30 km ( deeper than 10 hPa) if launched on small research balloons with volumes of 10000 m3 or less. The instruments are fully automated. Measurements of the mixing ratios of CFC-12 and SF6 will be made at least every 2 minutes. For data transmission a digital lightweight telemetry system will be developed that is based on standard ozone sonde components that are presently used for routine operations at various radiosonde and ozonesonde stations. The chlorofluorocarbon CFC-12 is a long-lived trace gas, that represents the most abundant source gas of total reactive chlorine, Cly, in the stratosphere and is a good tracer for dynamic transport processes. SF6, is an inert tracer, that provides information about the age of the stratospheric air. In combination with the digital ozonesonde these instruments form a lightweight balloon payload to study the vertical distribution of total reactive chlorine in the stratosphere and quantitatively investigate the corresponding ozone depletion potential in the probed airmass. General Information: Two lightweight automated in-situ gas-chromatographs will be developed for the measurement of the long-lived trace gases CFC-12 and SF6 with a time resolution of 1 to 2 minutes onboard stratospheric research balloons. Both instruments will use electron capture detectors (ECD) for identification of the measured species. The radio transmitter of the standard Vaisala radiosonde will be modified for use as a telemetry system to transmit the data provided by the gas chromatographs together with the ozone data that will be simultaneously measured by means of commercially available ozone sondes, e.g. Science Pump ECC or EN-SCI ECC sensors. Two telemetry channels will be used, one for the meteorological and ozone data (PTU and O3) and another one for the CFC and SF6 concentration data plus related housekeeping information. The following tangible results are expected from the project: -Two lightweight in-situ gas chromatographs for the measurement of SF6 and CFC-12, respectively, in the lower and middle stratosphere with a time resolution of 1 - 2 minutes. -An improved electrochemical ozonesonde with a two channel radio transmitter that is fully compatible with the standard Vaisala radiosonde link (400 MHz). -A new modulator that allows transmission of data provided by the serial interface of the internal control computers of the digital gas chromatographs at a rate of 1200 baud employing one of the telemetry channels of the new Vaisala transmitter. -A set of vertical profile measurements of O3, SF6 and CFC-12 performed during a test fligh
Das Projekt "Phaenomene der Wechselwirkung zwischen Tropfen und Wand, die fuer Benzinmotoren mit Direkteinspritzung von Bedeutung sind" wird vom Umweltbundesamt gefördert und von Robert Bosch GmbH durchgeführt. Objective: Direct Injection Spark Ignited (DISI) engines are superior to other SI engines in terms of fuel efficiency and CO2 emissions. The topic of DISI engine hydrocarbon requires a new consideration of the problem of droplet wall interaction. Wall films and pools of unburnt fuel formed by spray or droplet wall impingement is a major source of hydrocarbon emissions. To allow the effective design of DISI engines with respect to mixture formation, CFD tools are indispensable. These CFD codes commonly make use of Eulerian-Lagrangian methods for spray simulation and require appropriate droplet wall interaction models. It is the goal of this project to derive a general droplet wall interaction model applicable to the entire range of conditions present during operation of DISI engines. Description of the Work: Eulerian-Lagrangian methods track individual droplets along their trajectory until the droplets either evaporate, leave the simulation domain or impinge on a wall boundary. In the latter case correlations are required that link the pre and post-impingement conditions of a droplet and secondary droplets respectively. The special conditions in a DISI engine cylinder, i.e. small droplets, high temperatures and a wide range of pressures, do not allow for simple extrapolation of the results of numerous earlier investigations. Since a complete set of information is required for CFD simulations simultaneous measurements of droplet number, size, velocity vector and temperature in the hemisphere above the impact location, plus the resulting wall heat flux, are necessary. The project covers single droplet impacts, droplet chains, monosized sprays and finally polydisperse sprays and considers in particular the relevance of wall temperature and gas phase pressure. This measurement task will be distributed between several project partners according to the appropriateness of their test facilities. With the correlations evolving from these measurements a general droplet wall interaction model for single droplet impact is derived and then extended to encompass high droplet impact frequencies and number densities. Finally the developed interaction model is tested on real polydisperse spray applications under DISI conditions and validated with experimental measurements on injections into a constant volume chamber or optical DISI engine. Expected Results and Exploitation Plans: Besides a significant increase in understanding of the physical processes present in droplet wall impingement, a broad and consistent data base is collected. With this data a general statistical model of droplet wall interactions for single and multiple droplet wall interaction can be constructed, accounting for all major influencing parameters. The development of theoretical models will also be supported by this information. DWDIE results enhance the capability and precision of CFD codes to serve as design tools in the development of efficient and clean DISI engines.
Das Projekt "Entwicklung eines On-line Partikeldetektors" wird vom Umweltbundesamt gefördert und von Universität Duisburg, Fachbereich 9 Elektrotechnik, Fachgebiet Prozess- und Aerosolmesstechnik durchgeführt. In semiconductor technology clean process gases must be provided to manufacture large scale integrated chips. To prevent micro contamination of wafers, the process gases must be controlled by on-line detection of suspended particles. In this project the on-line particle detection is realized by means of optical method. Due to the low particle concentration, the entire cross section of the gas pipe has to be controlled. Thus it is necessary to install an illuminating plane of over 32 mm2 perpendicularly to gas flow. In clean gases paricles down to 0,1 my m must be detected. In this size range molecule noise leads to False-Count-Rate. To reduce the F.C.R. an additional illuminating plane is arranged parallel to the original one, and the F.C.R. is decreased via anew Pipeline-Cross-Correlation-Function, which is developed in this project. Using this P.C.C.F. method the influence of molecule noise on particle detection can be strongly reduced, and detection becomes possible without any dead time. To create the illuminatingplanes non-imaging optical elements are used, where beam bend is caused by reflection and diffraction exclusively. Applying computer simulation, the optical characteristics of those non-imaging optics are investigated, and it is shown that the scattered light intensity is nearly independent on local position of detected particles in the plane. The application of the non-imaging optics leads to high precision combined with low manufacturing costs. The results of optical simulation show that the pre-condition to detected particles with non-condition to detected particles with non-imaging optics in clean process gases in fulfilled, i.e. the entire gas flow is controlled, and the low detection limit is expanded down to 0,1 micron and local dependence of detector is smaller than 4 percent within measuring volume 6,4 mm x 6,4 mm. The algorithm of P.C.C.F. is based on classical cross-correlation. The difference between them is that output result from P.C.C.F. is a function of real time, t, but not a function of delaying time, t, which corresponds to the time difference between the two signals. Therefore, it is possible to set P.C.C.F. in on-line measurement. To examine the efficiency of P.C.C.F., a particle signal mixed with two acquired noise are simulated on computer. The results of simulation show that, in output process of P.C.C.F., the noise is reduced and the level of particle signal becomes higher. The signal-noise reatio is improved from one to four.
Das Projekt "Analysis of volatile non-methane hydrocarbons in air: improvement and harmonisation of the canister sampling and analysis" wird vom Umweltbundesamt gefördert und von Fraunhofer-Gesellschaft zur Förderung der Angewandten Forschung, Fraunhofer-Institut für Atmosphärische Umweltforschung durchgeführt. Objective: The AMOHA project aimed at improvement of NMHC measurement techniques based on sampling ambient air in stainless steel canisters. The project consisted of RTD and intercomparison parts. In the RTD part each step of the sampling and analysis procedure has been investigated, problem areas have been identified and recommendations for the best measurement practice had to be made. In the intercomparison part the analytical proficiency of up to 15 European laboratories has been tested in four annual intercomparisons of increasing complexity. Work programme: Procedures for cleaning canisters, sampling of ambient air, sample preconditioning, separation of individual NMHC compounds, their identification and quantification, preparation of stable standards and testing of NMHC gas mixtures have been investigated in the RTD part. In the intercomparison part we carried out four NMHC intercomparisons using synthetic 4 component, 30 component, 30 component plus pressurised ambient air test samples in the 1st, 2nd, and 3rd intercomparisons, respectively, and ambient air measurements in the 4th intercomparison. The results of each intercomparison were discussed at a workshop in order to obtain feedback on the measurement problems of the participants and to demonstrate that the problems can be overcome. The improved measurement practice has been described in standard operating procedures (SOPs). General Information: Accurate measurements of non-methane hydrocarbons (NMHCs) in ambient air are one of the major prerequisites to designing measures for the control of ozone precursor emissions and monitoring the efficiency of this control. NMHC measurements in ambient air are difficult because a large number of individual substances (30 and more) have to be identified and quantified at mixing ratios of usually less than 1 ppbv (10-9 volume ratio) in the presence of interfering substances. Previous intercomparisons in Europe and North America showed large differences between laboratories when measuring NMHCs in synthetic test and ambient air samples. Achievements: Currently used electropolished stainless steel canisters proved to be superior for NMHC measurements to silica lined and aluminium canisters, although the latter might offer advantages when other more polar volatile organic compounds are to be measured. Aluminium high-pressure cylinders performed better in terms of NMHC stability for pressurised ambient air sample than stainless steel high-pressure cylinders. Reactions of ozone with NMHCs in the ambient air sample influenced only the most reactive NMHCs (butadiene and isoprene), because of rapid destruction of ozone within the sampling pump and the canister. Several preconditioning procedures (drying and CO2 removal) were successfully tested. ... Prime Contractor: Fraunhofer-Gesellschaft zur Förderung der Angewandten Forschung, Fraunhofer-Institut für Atmosphärische Umweltforschung; Garmisch-Partenkirchen; Germany.
Das Projekt "Redox processes along gradients" wird vom Umweltbundesamt gefördert und von Universität Bayreuth, Lehrstuhl für Hydrologie, Limnologische Forschungsstation durchgeführt. The relevance of biogeochemical gradients for turnover of organic matter and contaminants is yet poorly understood. This study aims at the identification and quantification of the interaction of different redox processes along gradients. The interaction of iron-, and sulfate reduction and methanogenesis will be studied in controlled batch and column experiments. Factors constraining the accessibility and the energy yield from the use of these electron acceptors will be evaluated, such as passivation of iron oxides, re-oxidation of hydrogen sulfide on iron oxides. The impact of these constraints on the competitiveness of the particular process will then be described. Special focus will be put on the evolution of methanogenic conditions in systems formerly characterized by iron and sulfate reducing condition. As methanogenic conditions mostly evolve from micro-niches, methods to study the existence, evolution and stability of such micro-niches will be established. To this end, a combination of Gibbs free energy calculations, isotope fractionation and tracer measurements, and mass balances of metabolic intermediates (small pool sizes) and end products (large pool sizes) will be used. Measurements of these parameters on different scales using microelectrodes (mm scale), micro sampling devices for solutes and gases (cm scale) and mass flow balancing (column/reactor scale) will be compared to characterize unit volumes for organic matter degradation pathways and electron flow. Of particular interest will be the impact of redox active humic substances on the competitiveness of involved terminal electron accepting processes, either acting as electron shuttles or directly providing electron accepting capacity. This will be studied using fluorescence spectroscopy and parallel factor analysis (PARAFAC) of the gained spectra. We expect that the results will provide a basis for improving reactive transport models of anaerobic processes in aquifers and sediments.
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