High velocity structures in, and the X-ray emission from the LBV nebula around Eta Carinae

The Luminous Blue Variable star Eta Carinae is one of the most massive stars known. It underwent a giant eruption in 1843 in which the Homunculus nebula was created. ROSAT and ASCA data indicate the existence of a hard and a soft X-ray component which appear to be spatially distinct: a softer diffuse shell of the nebula around Eta Carinae and a harder point-like source centered on the star Eta Car. Astonishingly the morphology of the X-ray emission is very different from the optical appearance of the nebula. We present a comparative analysis of optical morphology, the kinematics, and the diffuse soft X-ray structure of the nebula around Eta Carinae. Our kinematic analysis of the nebula shows extremely high expansion velocities. We find a strong correlation between the X-ray emission and the knots in the nebula and the largest velocities, i.e. the X-ray morphology of the nebula around Eta Carinae is determined by the interaction between material streaming away from Eta Car and the ambient medium.Comment: 12 pages, 7 figures, A&A in press, same paper with images at full resolution available from http://www.ita.uni-heidelberg.de/~kweis/publications.htm

Cosmic rays in astrospheres

Cosmic rays passing through large astrospheres can be efficiently cooled inside these "cavities" in the interstellar medium. Moreover, the energy spectra of these energetic particles are already modulated in front of the astrospherical bow shocks. We study the cosmic ray flux in and around lambda Cephei as an example for an astrosphere. The large-scale plasma flow is modeled hydrodynamically with radiative cooling. We studied the cosmic ray flux in a stellar wind cavity using a transport model based on stochastic differential equations. The required parameters, most importantly, the elements of the diffusion tensor, are based on the heliospheric parameters. The magnetic field required for the diffusion coefficients is calculated kinematically. We discuss the transport in an astrospheric scenario with varying parameters for the transport coefficients. We show that large stellar wind cavities can act as sinks for the galactic cosmic ray flux and thus can give rise to small-scale anisotropies in the direction to the observer. Small-scale cosmic ray anisotropies can naturally be explained by the modulation of cosmic ray spectra in huge stellar wind cavities

The “green” electrochemical synthesis of periodate

High-grade periodate is relatively expensive, but is required for many sensitive applications such as the synthesis of active pharmaceutical ingredients. These high costs originate from using lead dioxide anodes in contemporary electrochemical methods and from expensive starting materials. A direct and cost-efficient electrochemical synthesis of periodate from iodide, which is less costly and relies on a readily available starting material, is reported. The oxidation is conducted at boron-doped diamond anodes, which are durable, metal-free, and nontoxic. The avoidance of lead dioxide ultimately lowers the cost of purification and quality assurance. The electrolytic process was optimized by statistical methods and was scaled up in an electrolysis flow cell that enhanced the space–time yields by a cyclization protocol. An LC-PDA analytical protocol was established enabling simple quantification of iodide, iodate, and periodate simultaneously with remarkable precision

Describing the Drying and Solidification Behavior of Single Suspension Droplets Using a Novel Unresolved CFD-DEM Simulation Approach

With increasing computational capacities and advances in numerical methods, a simulation-based process and product design approach for spray dried products has become the focus of many researchers. In this context, a novel unresolved CFD-DEM simulation approach for single suspension droplets is presented, which models the drying and solidification process in a hot gas environment. The solidification process is described by the formation of bonds between the primary particles in the suspension droplet, showing a plausible solidification behavior, which starts when a critical solid concentration is reached at the droplet surface. The drying conditions for the single-droplet simulations are determined from a large-scale spray dryer simulation for different droplet size classes. The resulting solid particles from the CFD-DEM simulation show a higher tendency to form hollow particles at high drying rates when the locking point is reached at earlier stages of the drying process. Using these results, suitable operating conditions for the spray dryer can be determined, which favor the formation of particles with a targeted morphology

Detection of interstellar oxidaniumyl: abundant H2O+ towards the star-forming regions DR21, Sgr B2, and NGC6334

We identify a prominent absorption feature at 1115 GHz, detected in first HIFI spectra towards high-mass star-forming regions, and interpret its astrophysical origin. The characteristic hyperfine pattern of the H2O+ ground-state rotational transition, and the lack of other known low-energy transitions in this frequency range, identifies the feature as H2O+ absorption against the dust continuum background and allows us to derive the velocity profile of the absorbing gas. By comparing this velocity profile with velocity profiles of other tracers in the DR21 star-forming region, we constrain the frequency of the transition and the conditions for its formation. In DR21, the velocity distribution of H2O+ matches that of the [CII] line at 158\mu\m and of OH cm-wave absorption, both stemming from the hot and dense clump surfaces facing the HII-region and dynamically affected by the blister outflow. Diffuse foreground gas dominates the absorption towards Sgr B2. The integrated intensity of the absorption line allows us to derive lower limits to the H2O+ column density of 7.2e12 cm^-2 in NGC 6334, 2.3e13 cm^-2 in DR21, and 1.1e15 cm^-2 in Sgr B2.Comment: Accepted for publication in A&

A New Method for Structured Integration of User Needs in Two Health Technology Development Projects: Action Sheets

An early integration of users and stakeholders is needed for a successful innovation process. Nonetheless, the integration of users is often hard to realize - especially when dealing with persons with chronic diseases. In addition, patients or users in general often are not able to formulate the requirements in a technical manner. Therefore, even if user requirements are collected, it is not certain that the developers know or understand \u27what is really wanted\u27. To overcome these \u27gaps\u27, we have developed so-called Action Sheets (AS). This article presents the use of AS in two projects: the development of health technologies for people with cancer (INFOPAT) and dementia (QuartrBack). Depending on the project context, group sessions were conducted with different stakeholders to identify the needs of (potential) users. Within the INFOPAT project, ten focus groups were conducted with patients, physicians and other healthcare professionals. In QuartrBack stakeholders like e.g. care professionals, technical assistance organizations and citizens participated in two focus groups and three world cafes. Their requirements were then \u27fed\u27 into the technology development by the use of AS. AS appear to be a promising tool to make user needs based on social values more tangible and implementable into technology development processes. In addition, it shows up that four phases seem to be necessary for transferring identified user and stakeholder needs into AS, which can therefore be seen as essential to translate non-technically formulated requirements into technically feasible ones. The case study shows as lessons learned that despite the successful integration of user needs, context-sensitive adjustments are still necessary