Filtern
Dokumenttyp
- Wissenschaftlicher Artikel (15) (entfernen)
Schlagworte
- Argania spinosa (2)
- Bodenwasser (2)
- Marokko (2)
- Satellitenfernerkundung (2)
- gypsum plaster (2)
- AFD (1)
- Abwasser (1)
- AfD (1)
- Anemometrie (1)
- Antarktis (1)
- Antiparasitäres Mittel (1)
- Behavioral model (1)
- Bewaldung (1)
- Bodenfruchtbarkeit (1)
- Bodenmikrobiologie (1)
- Bodenschutz (1)
- Brandverhalten (1)
- DNA isolation (1)
- Degradation (1)
- Einzugsgebiet (1)
- Enzymes (1)
- Europäische Union / Wasserrahmenrichtlinie (1)
- Evapotranspiration (1)
- Exposure time (1)
- Faser (1)
- Forest evapotranspiration (1)
- Gips (1)
- Gipsplatte (1)
- Grasslands (1)
- Grünland (1)
- HEXAGON (1)
- Hyperhidrose (1)
- Höhlensalamander (1)
- Klima (1)
- LAP (1)
- Lidar (1)
- Meteorologische Messung (1)
- Mitochondria (1)
- Modell (1)
- Modellierung (1)
- Nanopartikel (1)
- Neptungras (1)
- Neue Rechte (1)
- Optimierung (1)
- Paleogenetics (1)
- Phosphatgips (1)
- Phylogenetic analysis (1)
- Phylogenie (1)
- Physikalisch-chemische Eigenschaft (1)
- Polargebiete (1)
- Posidonia oceanica fibers (1)
- Salamander (1)
- Salamanders (1)
- Samenkeimung (1)
- Schafweide (1)
- Schwitzen (1)
- Seed germination (1)
- Sheep (1)
- Silber (1)
- Silver nanoparticles (1)
- Soil microbial community (1)
- Soil parameterization (1)
- Soil texture (1)
- Stadtforschung (1)
- Stadtplanung (1)
- Stress (1)
- Temperatur (1)
- Toxicity (1)
- Toxizität (1)
- Umweltfaktor (1)
- Verbreitungsökologie (1)
- Verbundwerkstoff (1)
- Virtuelle Umgebung (1)
- Wald (1)
- Wasserbilanz (1)
- Water Framework Directive (1)
- Water balance simulation (1)
- Wohnen (1)
- Wohnungspolitik (1)
- argan tree (1)
- behavioural ecology (1)
- change mapping (1)
- composite materials (1)
- correction factor (1)
- ecological modelling (1)
- fire performance (1)
- forest degradation (1)
- herpetology (1)
- housing (1)
- housing policy (1)
- local wastewater planning (1)
- new right (1)
- open-canopy woodland (1)
- phosphogypsum (1)
- physico-mechanical properties (1)
- plant architecture (1)
- tree density (1)
- urban and rural boundaries (1)
- urban studies (1)
- woody cover (1)
Institut
- Fachbereich 6 (15) (entfernen)
Background: Increasing exposure to engineered inorganic nanoparticles takes actually place in both terrestric and aquatic ecosystems worldwide. Although we already know harmful effects of AgNP on the soil bacterial community, information about the impact of the factors functionalization, concentration, exposure time, and soil texture on the AgNP effect expression are still rare. Hence, in this study, three soils of different grain size were exposed for up to 90 days to bare and functionalized AgNP in concentrations ranging from 0.01 to 1.00 mg/kg soil dry weight. Effects on soil microbial community were quantified by various biological parameters, including 16S rRNA gene, photometric, and fluorescence analyses.
Results: Multivariate data analysis revealed significant effects of AgNP exposure for all factors and factor combinations investigated. Analysis of individual factors (silver species, concentration, exposure time, soil texture) in the unifactorial ANOVA explained the largest part of the variance compared to the error variance. In depth analysis of factor combinations revealed even better explanation of variance. For the biological parameters assessed in this study, the matching of soil texture and silver species, and the matching of soil texture and exposure time were the two most relevant factor combinations. The factor AgNP concentration contributed to a lower extent to the effect expression compared to silver species, exposure time and physico–chemical composition of soil.
Conclusions: The factors functionalization, concentration, exposure time, and soil texture significantly impacted the effect expression of AgNP on the soil microbial community. Especially long-term exposure scenarios are strongly needed for the reliable environmental impact assessment of AgNP exposure in various soil types.
Finding behavioral parameterization for a 1-D water balance model by multi-criteria evaluation
(2019)
Evapotranspiration is often estimated by numerical simulation. However, to produce accurate simulations, these models usually require on-site measurements for parameterization or calibration. We have to make sure that the model realistically reproduces both, the temporal patterns of soil moisture and evapotranspiration. In this study, we combine three sources of information: (i) measurements of sap velocities; (ii) soil moisture; and (iii) expert knowledge on local runoff generation and water balance to define constraints for a “behavioral” forest stand water balance model. Aiming for a behavioral model, we adjusted soil moisture at saturation, bulk resistance parameters and the parameters of the water retention curve (WRC). We found that the shape of the WRC influences substantially the behavior of the simulation model. Here, only one model realization could be referred to as “behavioral”. All other realizations failed for a least one of our evaluation criteria: Not only transpiration and soil moisture are simulated consistently with our observations, but also total water balance and runoff generation processes. The introduction of a multi-criteria evaluation scheme for the detection of unrealistic outputs made it possible to identify a well performing parameter set. Our findings indicate that measurement of different fluxes and state variables instead of just one and expert knowledge concerning runoff generation facilitate the parameterization of a hydrological model.
Species can show strong variation of local abundance across their ranges. Recent analyses suggested that variation in abundance can be related to environmental suitability, as the highest abundances are often observed in populations living in the most suitable areas. However, there is limited information on the mechanisms through which variation in environmental suitability determines abundance. We analysed populations of the microendemic salamander Hydromantes flavus, and tested several hypotheses on potential relationships linking environmental suitability to population parameters. For multiple populations across the whole species range, we assessed suitability using species distribution models, and measured density, activity level, food intake and body condition index. In high-suitability sites, the density of salamanders was up to 30-times higher than in the least suitable ones. Variation in activity levels and population performance can explain such variation of abundance. In high-suitability sites, salamanders were active close to the surface, and showed a low frequency of empty stomachs. Furthermore, when taking into account seasonal variation, body condition was better in the most suitable sites. Our results show that the strong relationship between environmental suitability and population abundance can be mediated by the variation of parameters strongly linked to individual performance and fitness.
In the present study a non-motion-stabilized scanning Doppler lidar was operated on board of RV Polarstern in the Arctic (June 2014) and Antarctic (December 2015– January 2016). This is the first time that such a system measured on an icebreaker in the Antarctic. A method for a motion correction of the data in the post-processing is presented.
The wind calculation is based on vertical azimuth display (VAD) scans with eight directions that pass a quality control. Additionally a method for an empirical signal-tonoise ratio (SNR) threshold is presented, which can be calculated for individual measurement set-ups. Lidar wind profiles are compared to total of about 120 radiosonde profiles and also to wind measurements of the ship.
The performance of the lidar measurements in comparison with radio soundings generally shows small root mean square deviation (bias) for wind speed of around 1ms-1(0.1ms-1) and for wind direction of around 10 (1). The post-processing of the non-motion-stabilized data shows comparably high quality to studies with motion-stabilized systems.
Two case studies show that a flexible change in SNR threshold can be beneficial for special situations. Further the studies reveal that short-lived low-level jets in the atmospheric boundary layer can be captured by lidar measurements with a high temporal resolution in contrast to routine radio soundings. The present study shows that a non-motionstabilized Doppler lidar can be operated successfully on an
icebreaker. It presents a processing chain including quality control tests and error quantification, which is useful for further measurement campaigns.
Addition of Phosphogypsum to Fire-Resistant Plaster Panels:
A Physic–Mechanical Investigation
(2023)
Gypsum (GPS) has great potential for structural fire protection and is increasingly used in construction due to its high-water retention and purity. However, many researchers aim to improve its physical and mechanical properties by adding other organic or inorganic materials such as fibers, recycled GPS, and waste residues. This study used a novel method to add non-natural GPS from factory waste (phosphogypsum (PG)) as a secondary material for GPS. This paper proposes to mix these two materials to properly study the effect of PG on the physico-mechanical properties and fire performance of two Tunisian GPSs (GPS1 and GPS2). PG initially replaced GPS at 10, 20, 30, 40, and 50% weight percentage (mixing plan A). The PGs were then washed with distilled water several times. Two more mixing plans were run when the pH of the PG was equal to 2.4 (mixing plan B), and the pH was equal to 5 (mixing plan C). Finally, a comparative study was conducted on the compressive strength, flexural strength, density, water retention, and mass loss levels after 90 days of drying, before/after incineration of samples at 15, 30, 45, and 60 min. The results show that the mixture of GPS1 and 30% PG (mixing plan B) obtained the highest compressive strength (41.31%) and flexural strength (35.03%) compared to the reference sample. The addition of 10% PG to GPS1 (mixing plan A) improved fire resistance (33.33%) and the mass loss (17.10%) of the samples exposed to flame for 60 min compared to GPS2. Therefore, PG can be considered an excellent insulating material, which can increase physico-mechanical properties and fire resistance time of plaster under certain conditions.