Das digitale geologische Strukturmodell Bitterfeld als neuer Baustein in der Sanierungsforschung

Zur Erfassung, Bewertung und Behandlung gro?r?umiger Grundwasserkontaminationen ist die Kenntnis des geologischen Aufbaus des Untergrundes für eine Vorhersage des Schadstoffverhaltens eine unbedingte Voraussetzung. Im Rahmen des SAFIRA-Projektes ist für ein Modellgebiet des ?GP Bitterfeld/Wolfen die Architektur der Lockergesteinsaquifere in ein digitales geologisches Raummodell überführt worden. Basierend auf 125 Bohraufschlüssen, mit 28 vernetzten Profilschnitten, konnte die lithologische und strukturelle Heterogenit?t in 31 lithostratigraphischen Sedimentationsk?rpern plausibel auf der Basis eines 10 × 10 m-Rasters GIS-gestützt abgebildet werden. Die Zuordnung hydraulischer Parameter zu den einzelnen Sedimentk?rpern erlaubt die sp?tere Nutzung mit Str?mungs- und Transportmodellen. Das in Kombination von Profilschnitten und Fl?chendaten generierte Raummodell erm?glicht neben beliebigen Visualisierungen auch die Berechnung von Kubaturen einzelner Schichten. Dies ist z. B. bei der Restbraunkohle für die Absch?tzung von Schadstoffretentionen und -remobilisierungen im Untergrund von erheblicher Bedeutung. Das hier vorgestellte geologische 3-D-Strukturmodell ist die Grundlage für die weiteren Bearbeitungen zur Bewertung von Umweltauswirkungen und Sanierungsvarianten.     

Hydrophobic recovery of atmospheric pressure plasma treated surfaces of Wood-Polymer Composites (WPC)

In this study, the behavior of atmospheric pressure plasma treated surfaces of Wood-Polymer Composites (WPC) was investigated as a function of time and environmental conditions. The surfaces of injection molded WPC based on polypropylene (PP) and polyethylene (PE) were treated by a dielectric barrier discharge (DBD) and subsequently aged under various conditions. The wettability as an indicator for change of the composite surface was assessed using water contact angle. In addition, a calculation for half-time of the contact angles was developed to predict the time span which is needed for recovery of hydrophobicity. The results showed a major influence of temperature and time, whereas the humidity only at storing conditions of 60?°C and 75% relative humidity showed a distinct effect on the activated surface. The effect of DBD treatment was stable for more than one week in the climates 20?°C and 0% RH and 20?°C and 65% RH.     

PF-bonded particleboards from AKD-modified chips

Alkyl ketene dimer (AKD) was used as a hydrophobic agent for PF-bonded particleboards. In contrast to conventionally used paraffin, AKD can be covalently bonded to the chip surface by esterification with wood hydroxyl groups. FTIR analyses before and after toluene extractions indicated that only a small amount of the applied AKD is chemically bonded. Wettability studies on veneer strips suggested that particularly the bonded AKD accounts for the surface hydrophobicity. A subsequent spraying of AKD and PF resin on the chips that were pressed for 15, 30, and 60 s?mm^-1 (Process 1) did not result in decreased thickness swelling and water uptake as compared to the control boards. In Process 2, chips were cured (130 °C/6, 12, 24 h) prior to pressing (15 s?mm^-1) which did not impart significant hydrophobicity either. The low efficacy of AKD as hydrophobic agent in Process 1 is attributed to the hydrolysis of AKD by water vapor during pressing. The low hydrophobic effect of AKD in Process 2 is ascribed to a saponification of esters between AKD and wood hydroxyl groups by the alkaline PF resin.     

Experimental evidence of a linear relationship between inorganic mercury loading and methylmercury accumulation by aquatic biota

Developing effective regulations on mercury (Hg) emissions requires a better understanding of how atmospheric Hg deposition affects methylmercury (MeHg) levels in aquatic biota. This study tested the hypothesis that MeHg accumulation in aquatic food webs is related to atmospheric Hg deposition. We simulated a range of inorganic Hg deposition rates by adding isotopically enriched Hg(II) (90.9% 202Hg) to 10-m diameter mesocosms in a boreal lake. Concentrations of experimentally added ("spike") Hg were monitored in zooplankton, benthic invertebrates, and fish. Some Hg(II) added to the mesocosms was methylated and incorporated into the food web within weeks, demonstrating that Hg(II) deposited directly to aquatic ecosystems can become quickly available to biota. Relationships between Hg(II) loading rates and spike MeHg concentrations in zooplankton, benthic invertebrates, and fish were linear and significant. Furthermore, spike MeHg concentrations in the food web were directly proportional to Hg(II) loading rates (i.e., a percent change in Hg(II) loading rate resulted in, statistically, the same percent change in MeHg concentration). This is the first experimental determination of the relationship between Hg(II) loading and MeHg bioaccumulation in aquatic biota. We conclude that changes in atmospheric Hg deposition caused by increases or decreases in Hg emissions will ultimately affect MeHg levels in aquatic food webs.     

Non-destructive evaluation of grain angle, moisture content and density of spruce with microwaves

Non-destructive evaluation of the physical properties of wood is a key task in modern wood manufacturing processes. Due to a rapidly increasing production speed, fast, non-contacting, reliable and robust measurement systems are demanded by the wood industry. Common moisture meters are able to reasonably cope with industrial needs. However, modern detection of wood grain angle deviation remains an unresolved issue. Microwave technology features the ability to simultaneously identify grain angle, density and moisture content of wood by measuring attenuation, phase shift, and depolarization of transmitted signals. This paper reports on series of microwave measurements revealing the desired physical properties for spruce. Samples were tested at different frequencies in the range from 8 to 12 GHz. For each frequency the grain angles were identified with standard errors of maximum 0.15° (measuring range from ?90° to +90°). Standard errors in the determination of moisture density were less or equal 1.8 kg/m³ (measuring range from 27 to 56 kg/m³). Standard errors determining moisture content were maximum 0.47 % (measuring range from 7.6 to 14 %), and standard errors for dry density were maximum 11.3 kg/m³ (measuring range from 284 to 492 kg/m³).     

Optimierung des Eigenspannungszustands kaltfließgepresster austenitischer Stähle durch einen kontrollierten Ausstoßvorgang

Forschung im Ingenieurwesen - Ausgehend von vorherigen Ergebnissen zur Prozessoptimierung fließgepresster Proben aus dem austenitischen Werkstoff 1.4404 mittels einer aktiven...     

The HüGaProp-Container: Analytical Infrastructure for the Carbon2Chem® Challenge

The utilization of industrial off-gases as raw material requires a detailed knowledge on their time-depending composition, especially with regard to trace components. Within the framework of the HüGaProp project (Hüttengas Properties) a measuring container and the analytical methods for the characterization of trace components in the three raw metallurgical gases was developed. The mobile container is deployed in the project Carbon2Chem® to characterize the available off-gases at a steel mill and provide fundamental data to determine the required gas cleaning as well as the background for the further process design.