Mischungsentwicklung für funktional gradierten Betonbau

Um eine funktionale Gradierung im Betonbau zu erzielen, werden zwei Betonmischungen mit konträren Eigenschaften benötigt. Je nach Herstellungsverfahren sind die Materialzusammensetzung und damit die Verarbeitbarkeit, Dichte und Festigkeit beider Mischungen anzupassen. Grundsätzlich soll dabei eine der beiden Mischungen gute Festigkeitseigenschaften bei minimaler Porosität zeigen und für die Aufgaben des statischen Lastabtrags geeignet sein. Die zweite Mischung hingegen ist durch einen hohen Luftporenanteil sehr leicht und wenig fest, kann dafür jedoch mit verbesserten Wärmedämmwerten auch bauphysikalische Anforderungen erfüllen. Ziel in einem interdiziplinären Forschungsvorhaben ist, beide Mischungen in unterschiedlichen Verfahren stufenlos und kontinuierlich ineinander zu überführen und somit funktional gradierte Betonbauteile in einem teilautomatisierten Verfahren herzustellen

The influence of ash tree sawdust acid treatment on the removal of crude oil from water surfaces

Agricultural and timber industry wastes may constitute a significant source of promising oil sorption materials. In this study the potential application of Fráxinus excélsior ash tree sawdust as sorption material for crude oil removal was investigated. The effect of acid treatment on physicochemical and sorption properties of sawdust was studied in a batch system. Oil sorption capacity and water uptake of sorption materials in static system were evaluated. For the determination of raw and treated samples structure and surface changes X-ray diffraction analysis, atomic force microscopy, FTIR spectroscopy and contact angle evaluation were used. The highest oil sorption capacity was shown by 3% HNO3 treated sawdust, 43.2% and 37.4% increase of oil sorption capacity for Devonian oil and Carbon oil, respectively, was observed in comparison with untreated sawdust. The exhibited reduction of modified sawdust water uptake indicated the increase of sorbent material hydrophobicity that was confirmed by the results of contact angle determination. Based on atomic force microscopy results, the surface roughness of treated sawdust was shown to be enhanced that could be a primary factor affecting on oil sorption capacity improvement. Thus, acid treated ash tree sawdust was shown to have improved oil sorption and physicochemical characteristics for crude oil removal

The histochemistry of thiols and disulphides. II. Methodology of differential staining

The reduction of disulphide bonds by various mercaptans and tri- n -butylphosphine (TBP) has been examined in paraffin sections of rat tissues. A ‘re-reduction’ procedure demonstrating any residual disulphides shows that nearly equivalent endpoints are reached by all of the reagents at pH 8.5 and room temperature, though at greatly differing rates. TBP is the reductant of choice in that it acts rapidly, cannot cause the thiolation which is more or less pronounced with certain mercaptans and least reverses the prior alkylation of native thiol groups by iodoacetate or N-substituted malemides. Supporting studies establish that, except in highly compact structures, native as well as generated thiol groups can be visualized with satisfactory completeness and specificity by N-(4-aminophenyl)maleimide followed by a diazotization and coupling sequence. These findings provide the basis for the selective staining of disulphides, either alone or differentiated from native thiols in the same section.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42844/1/10735_2005_Article_BF01003139.pd

Detecting impacts of extreme events with ecological in situ monitoring networks

Extreme hydrometeorological conditions typically impact ecophysiological processes on land. Satellite-based observations of the terrestrial biosphere provide an important reference for detecting and describing the spatiotemporal development of such events. However, in-depth investigations of ecological processes during extreme events require additional in situ observations. The question is whether the density of existing ecological in situ networks is sufficient for analysing the impact of extreme events, and what are expected event detection rates of ecological in situ networks of a given size. To assess these issues, we build a baseline of extreme reductions in the fraction of absorbed photosynthetically active radiation (FAPAR), identified by a new event detection method tailored to identify extremes of regional relevance. We then investigate the event detection success rates of hypothetical networks of varying sizes. Our results show that large extremes can be reliably detected with relatively small networks, but also reveal a linear decay of detection probabilities towards smaller extreme events in log–log space. For instance, networks with  ≈  100 randomly placed sites in Europe yield a  ≥  90 % chance of detecting the eight largest (typically very large) extreme events; but only a  ≥  50 % chance of capturing the 39 largest events. These findings are consistent with probability-theoretic considerations, but the slopes of the decay rates deviate due to temporal autocorrelation and the exact implementation of the extreme event detection algorithm. Using the examples of AmeriFlux and NEON, we then investigate to what degree ecological in situ networks can capture extreme events of a given size. Consistent with our theoretical considerations, we find that today's systematically designed networks (i.e. NEON) reliably detect the largest extremes, but that the extreme event detection rates are not higher than would be achieved by randomly designed networks. Spatio-temporal expansions of ecological in situ monitoring networks should carefully consider the size distribution characteristics of extreme events if the aim is also to monitor the impacts of such events in the terrestrial biosphere.</p

Pd Nanoparticles and Thin Films for Room Temperature Hydrogen Sensor

We report the application of palladium nanoparticles and thin films for hydrogen sensor. Electrochemically grown palladium particles with spherical shapes deposited on Si substrate and sputter deposited Pd thin films were used to detect hydrogen at room temperature. Grain size dependence of H2sensing behavior has been discussed for both types of Pd films. The electrochemically grown Pd nanoparticles were observed to show better hydrogen sensing response than the sputtered palladium thin films. The demonstration of size dependent room temperature H2sensing paves the ways to fabricate the room temperature metallic and metal–metal oxide semiconductor sensor by tuning the size of metal catalyst in mixed systems. H2sensing by the Pd nanostructures is attributed to the chemical and electronic sensitization mechanisms

American Thyroid Association Design and Feasibility of a Prospective Randomized Controlled Trial of Prophylactic Central Lymph Node Dissection for Papillary Thyroid Carcinoma

Background: The role of prophylactic central lymph node dissection in papillary thyroid cancer (PTC) is controversial in patients who have no pre- or intraoperative evidence of nodal metastasis (clinically N0; cN0). The controversy relates to its unproven role in reducing recurrence rates while possibly increasing morbidity (permanent hypoparathyroidism and unintentional recurrent laryngeal nerve injury). Methods and Results: We examined the design and feasibility of a multi-institutional prospective randomized controlled trial of prophylactic central lymph node dissection in cN0 PTC. Assuming a 7-year study with 4 years of enrollment, 5 years of average follow-up, a recurrence rate of 10% after 7 years, a 25% relative reduction in the rate of the primary endpoint (newly identified structural disease; i.e., persistent, recurrent, or distant metastatic disease) with central lymph node dissection and an annual dropout rate of 3%, a total of 5840 patients would have to be included in the study to achieve at least 80% statistical power. Similarly, given the low rates of morbidity, several thousands of patients would need to be included to identify a significant difference in rates of permanent hypoparathyroidism and unintentional recurrent laryngeal nerve injury. Conclusion: Given the low rates of both newly identified structural disease and morbidity after surgery for cN0 PTC, prohibitively large sample sizes would be required for sufficient statistical power to demonstrate significant differences in outcomes. Thus, a prospective randomized controlled trial of prophylactic central lymph node dissection in cN0 PTC is not readily feasible.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98487/1/thy%2E2011%2E0317.pd

Investigating Behaviour and Population Dynamics of Striped Marlin (Kajikia audax) from the Southwest Pacific Ocean with Satellite Tags

Behaviour and distribution of striped marlin within the southwest Pacific Ocean were investigated using electronic tagging data collected from 2005–2008. A continuous-time correlated random-walk Kalman filter was used to integrate double-tagging data exhibiting variable error structures into movement trajectories composed of regular time-steps. This state-space trajectory integration approach improved longitude and latitude error distributions by 38.5 km and 22.2 km respectively. Using these trajectories as inputs, a behavioural classification model was developed to infer when, and where, ‘transiting’ and ‘area-restricted’ (ARB) pseudo-behavioural states occurred. ARB tended to occur at shallower depths (108±49 m) than did transiting behaviours (127±57 m). A 16 day post-release period of diminished ARB activity suggests that patterns of behaviour were affected by the capture and/or tagging events, implying that tagged animals may exhibit atypical behaviour upon release. The striped marlin in this study dove deeper and spent greater time at ≥200 m depth than those in the central and eastern Pacific Ocean. As marlin reached tropical latitudes (20–21°S) they consistently reversed directions, increased swimming speed and shifted to transiting behaviour. Reversals in the tropics also coincided with increases in swimming depth, including increased time ≥250 m. Our research provides enhanced understanding of the behavioural ecology of striped marlin. This has implications for the effectiveness of spatially explicit population models and we demonstrate the need to consider geographic variation when standardizing CPUE by depth, and provide data to inform natural and recreational fishing mortality parameters

Is Mercury Orange a selective stain for thiols?

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42852/1/10735_2005_Article_BF01005240.pd