Public exhibit for demonstrating the quantum of electrical conductance

We present a new robust setup that explains and demonstrates the quantum of electrical conductance for a general audience and which is continuously available in a public space. The setup allows users to manually thin a gold wire of several atoms in diameter while monitoring its conductance in real time. During the experiment, a characteristic step-like conductance decrease due to rearrangements of atoms in the cross-section of the wire is observed. Just before the wire breaks, a contact consisting of a single atom with a characteristic conductance close to the quantum of conductance can be maintained up to several seconds. The setup is operated full-time, needs practically no maintenance and is used on different educational levels

A theory on the vertical dispersal of splash-borne pathogen units influenced by arable crop characteristics

An analytical mechanistic model was proposed to study the vertical spread of splash-borne spores in arable crop canopies. Three crop types were considered, with different LAI distributions. The influences of crop characteristics and rain properties on vertical spread were investigated. The LAI affected the amount of rain being intercepted by the canopy and the vertical displacement of splashed spores. Splash dispersal was concentrated in the upper canopy layers in a crop having LAI constant or increasing with height. Splash probabilities were greatest and most spores were intercepted in the layers just beneath the upper layers in a crop having LAI decreasing with height

Application of a finite-difference modeling scheme for ultrasonic defect characterization

Modeling schemes, which compute the propagation of ultrasonic wave fields, serve as research tools in NDE. The objectives to use such schemes are diverse. Firstly, they may be used to set the requirements for the ultrasonic data acquisition method and the processing algorithm. Secondly, they may be used to improve understanding of the actual measurement, i.e. for interpretation. Thirdly, they may play a central role in the inversion of the measurement for defect characterization, i.e. model driven inversion and neural network training

A theory on the vertical dispersal of splash-borne pathogen units influenced by arable crop characteristics

An analytical mechanistic model was proposed to study the vertical spread of splash-borne spores in arable crop canopies. Three crop types were considered, with different LAI distributions. The influences of crop characteristics and rain properties on vertical spread were investigated. The LAI affected the amount of rain being intercepted by the canopy and the vertical displacement of splashed spores. Splash dispersal was concentrated in the upper canopy layers in a crop having LAI constant or increasing with height. Splash probabilities were greatest and most spores were intercepted in the layers just beneath the upper layers in a crop having LAI decreasing with height

Decoherence of Flux Qubits Coupled to Electronic Circuits

On the way to solid-state quantum computing, overcoming decoherence is the central issue. In this contribution, we discuss the modeling of decoherence of a superonducting flux qubit coupled to dissipative electronic circuitry. We discuss its impact on single qubit decoherence rates and on the performance of two-qubit gates. These results can be used for designing decoherence-optimal setups.Comment: 16 pages, 5 figures, to appear in Advances in Solid State Physics, Vol. 43 (2003

The conceptual design of SeamFrame

This project deliverable provides the underlying architecture of a concept for linking models and databases and it provides the design of SeamFrame, delivering its architecture to provide an integration framework for models and simulation algorithms, supported by procedures for data handling and spatial representation, quality control, output visualization and documentatio

Highly abundant HCN in the inner hot envelope of GL 2591: probing the birth of a hot core?

We present observations of the v2=0 and vibrationally excited v2=1 J=9-8 rotational lines of HCN at 797 GHz toward the deeply embedded massive young stellar object GL 2591, which provide the missing link between the extended envelope traced by lower-J line emission and the small region of hot (T_ex >= 300 K), abundant HCN seen in 14 micron absorption with the Infrared Space Observatory (ISO). The line ratio yields T_ex=720^+135_-100 K and the line profiles reveal that the hot gas seen with ISO is at the velocity of the protostar, arguing against a location in the outflow or in shocks. Radiative transfer calculations using a depth-dependent density and temperature structure show that the data rule out a constant abundance throughout the envelope, but that a model with a jump of the abundance in the inner part by two orders of magnitude matches the observations. Such a jump is consistent with the sharp increase in HCN abundance at temperatures >~230 K predicted by recent chemical models in which atomic oxygen is driven into water at these temperatures. Together with the evidence for ice evaporation in this source, this result suggests that we may be witnessing the birth of a hot core. Thus, GL 2591 may represent a rare class of objects at an evolutionary stage just preceding the `hot core' stage of massive star formation.Comment: Accepted by ApJ Letters, 11 pages including 3 figures, uses AASTe

Modeling satellite gravity gradient data to derive density, temperature, and viscosity structure of the Antarctic lithosphere

In this study we combine seismological and petrological models with satellite gravity gradient data to obtain the thermal and compositional structure of the Antarctic lithosphere. Our results indicate that Antarctica is largely in isostatic equilibrium, although notable anomalies exist. A new Antarctic Moho depth map is derived that fits the satellite gravity gradient anomaly field and is in good agreement with independent seismic estimates. It exhibits detailed crustal thickness variations also in areas of East Antarctica that are poorly explored due to sparse seismic station coverage. The thickness of the lithosphere in our model is in general agreement with seismological estimates, confirming the marked contrast between West Antarctica (<100 km) and East Antarctica (up to 260 km). Finally, we assess the implications of the temperature distribution in our model for mantle viscosities and glacial isostatic adjustment. The upper mantle temperatures we model are lower than obtained from previous seismic velocity studies. This results in higher estimated viscosities underneath West Antarctica. When combined with present‐day uplift rates from GPS, a bulk dry upper mantle rheology appears permissible

How to predict transfer of training? Investigating the application of the unified model of task-specific motivation

Transfer motivation is an important factor influencing transfer of training. However, earlier research often did not investigate transfer motivation as a multidimensional construct. The unified model of task-specific motivation (UMTM) takes into account that (transfer) motivation is multidimensional by including both affective and cognitive motivational components and their antecedents. Prior research has provided evidence that the UMTM can predict self-reported transfer of training, but is unclear whether it also can predict transfer reported by expert external raters. Moreover, it is unclear whether controlling for prior knowledge matters for the relationship between transfer motivation and transfer of training. This study improves on existing research by accounting for both of these gaps in the literature. Data were collected among 299 participants who filled in a questionnaire about the UMTM components directly after attending a writing training. They also handed in written documents before, and 6 weeks after the training, which were rated on transfer by trainers. Outcomes showed that components of the UMTM positively predict externally reported transfer when prior knowledge was controlled for. The outcomes imply that the UMTM has predictive value for transfer of training and points out which factors influence whether transfer does or does not occur