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Kruger E.,Geisenheim Research Center | Josuttis M.,RheinMain University of Applied science
Acta Horticulturae

Berries are produced throughout the world under diverse environmental conditions. Moreover, in the last decade, berry production for the fresh market actually experienced great changes like out-of-season production or cultivation in non-traditional growing areas. In the context of globalisation, cultivars of all berry species are increasingly grown at sites with different climatic conditions than those where they originally were bred. Moreover, climate change will affect climatic conditions for all berry fruit. With regard to these challenges, the need of a better understanding of the potential yield development, endo-dormancy, winter hardiness and chilling requirement under open-field conditions are stressed. Berry fruit contain high levels of phytochemicals like ascorbic acid and diverse polyphenols and are a rich source of antioxidants. Beside genotype, which is the main factor determining the concentration of the phytochemicals, diverse growing conditions can influence the amount of the bioactives. Here, the effect of different growing sites, seasonal variation, protected cultivation systems and cultivation with mulch material are presented and discussed. Source

Schaefer J.,RheinMain University of Applied science
IEEE/IFIP NOMS 2014 - IEEE/IFIP Network Operations and Management Symposium: Management in a Software Defined World

Future personal living environments feature an increasing number of convenience-, health- and security-related applications provided by distributed services, which do not only support users but require tasks such as installation, configuration and continuous administration. These tasks are becoming tiresome, complex and error-prone. One way to escape this situation is to enable service platforms to configure and manage themselves. The approach presented here extends services with semantic descriptions to enable platform-independent autonomous service level management using model driven architecture and autonomic computing concepts. It has been implemented as a OSGi-based semantic autonomic manager, whose concept, prototypical implementation and evaluation are presented. © 2014 IEEE. Source

Sachser R.,Goethe University Frankfurt | Reizh H.,Goethe University Frankfurt | Reizh H.,RheinMain University of Applied science | Huzel D.,Goethe University Frankfurt | And 2 more authors.
ACS Applied Materials and Interfaces

In the majority of cases, nanostructures prepared by focused electron beam induced deposition employing an organometallic precursor contain predominantly carbon-based ligand dissociation products. This is unfortunate with regard to using this high-resolution direct-write approach for the preparation of nanostructures for various fields, such as mesoscopic physics, micromagnetism, metaoptical phenomena in the visible spectral range, or others. Following early attempts of postprocessing Pt-based structures prepared by focused electron beam induced deposition at several hundred degrees Celsius in a reactive gas atmosphere, recent work has focused on developing in situ purification processes by using a stationary O2 flux in combination with electron irradiation to oxidize the carbonaceous component of the deposits. Here we show that this purification process is driven by the catalytic activity of Pt and in fact does not rely on the parallel electron irradiation process to function, if the O2 exposure is done in a pulsed fashion. We suggest a multistep cleaning mechanism which results in pure, nanoporous Pt. By suitably chosen beam parameters, high-resolution Pt dot and line structures with dimensions below 10 nm can thus be conveniently obtained. In temperature-dependent resistance measurements, we find the typical metallic behavior of Pt. In low-temperature magnetoresistance measurements, we see clear evidence for weak antilocalization effects and deduce a dephasing length of 234 nm at 1.2 K. We consider this to be a promising starting point for developing this approach into a versatile preparation technique for Pt-based mesoscopic structures, in particular since the purification process can be run in parallel on different deposits. We furthermore anticipate that our results will spur further research on purification approaches for nanostructures prepared by focused electron beam induced deposition containing a catalytically active metal species such as Pd-, Fe-, or Cobased deposits. © 2014 American Chemical Society. Source

Krewski A.,RheinMain University of Applied science
IEEE Antennas and Propagation Society, AP-S International Symposium (Digest)

In the last two decades a trend toward the new type of aircraft design has developed. The Unmanned Areal Vehicles (UAVs) and further Unmanned Combat Areal Vehicles (UCAVs) are supposed to support and ultimately may supersede manned aircraft in the future missions. The wireless data link with these vehicles uses High Frequency (HF) band (from 3 MHz to 30 MHz) due to atmospheric low-attenuation window that exists in this frequency range. It allows to use ionosphere as a reflector to allow non-Line-of-Sight (LOS) communication beyond the Earth's horizon. However, typically the antennas for HF suffer from low efficiency and narrow bandwidth as they are electrically small. In the present paper the whole airframe of the craft is used as a radiator which significantly increases the bandwidth and efficiency of the resulting antenna. Moreover, the analysis of characteristic modes on an example UAV airframe led to the concept of incorporating two couplers into design of the aircraft wings. Both couplers excite mutually orthogonal characteristic modes on the UAV's airframe which enable realization of an 2-port Multiple Input - Multiple Output (MIMO) antenna system for High Frequency (HF) band. © 2013 IEEE. Source

Bouezzeddine M.,RheinMain University of Applied science
2016 10th European Conference on Antennas and Propagation, EuCAP 2016

To build a 4-port MIMO antenna system, we take recourse to characteristic modes of a femto-cell Customer Premises Equipment (CPE). A separate monopole antenna is mounted at top of the box, in addition to couplers used for exciting characteristic modes. By symmetry, high isolation is guaranteed between the radiation modes, constructed out of characteristic modes, and the monopole. In this paper, we present a study for matching separately the monopole antenna by terminating the non-fed port of the decoupling network of the chassis modes. The termination in question can provide a free parameter for tuning the monopole. © 2016 European Association of Antennas and Propagation. Source

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