Nitrogen‐doped graphene as an alternative to ecotoxic zinc oxide in rubbers

Zinc oxide (ZnO) is an essential ingredient in industrial rubber production; it regulates the onset of vulcanization, accelerates the kinetics of vulcanization, and improves the mechanical properties of rubber. However, environmental pollution with ZnO is a concern because it is recognized to be significantly ecotoxic and might also have adverse effects on human health. One of the major sources of ZnO environmental pollution is rubber items, tires in particular. Nitrogen (N)‐doped graphene is a promising next‐generation catalyst. We show here that the replacement of 3 phr ZnO by just 0.1 phr N‐doped graphene in styrene–butadiene rubber reduced the vulcanization onset time by more than a factor of two while retaining the fast vulcanization kinetics and enhancing the tensile strength in comparison with rubber with just ZnO. A shorter vulcanization time implies energy savings, which, together with the nontoxicity of N‐graphene, should make the resulting rubbers substantially more environmentally friendly. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46116.     

Dye solar modules for facade applications: Recent results from project ColorSol

With respect to a first market introduction, one advantage of dye solar cell (DSC) modules is the combination of photovoltaic (PV) solar electricity with decorative aspects. We report on the recent results achieved in the frame of the German project ColorSol. The project focuses on the application field of building-integrated PVs (facades, PV-glazing, etc.). Design concepts, as well as scenarios for the application of the DSC technology in architecture and facade planning are developed and the application potential is quantified in cooperation with potential users. Prototypes of glass facade elements (70 cm×200 cm) have been developed which consist of several serially interconnected DSC modules each with a size of 30 cm×30 cm. The results of module characteristics under various outdoor illumination conditions and under partial shading are reported. Visual impressions of the DSC facade elements are presented.     

Fluorescence-Based Nanoparticle Tracking Analysis and Flow Cytometry for Characterization of Endothelial Extracellular Vesicle Release

As extracellular vesicles (EVs) have become a prominent topic in life sciences, a growing number of studies are published on a regular basis addressing their biological relevance and possible applications. Nevertheless, the fundamental question of the true vesicular nature as well as possible influences on the EV secretion behavior have often been not adequately addressed. Furthermore, research regarding endothelial cell-derived EVs (EndoEVs) often focused on the large vesicular fractions comprising of microvesicles (MV) and apoptotic bodies. In this study we aimed to further extend the current knowledge of the influence of pre-isolation conditions, such as cell density and conditioning time, on EndoEV release from human umbilical vein endothelial cells (HUVECs). We combined fluorescence nanoparticle tracking analysis (NTA) and the established fluorescence-triggered flow cytometry (FT-FC) protocol to allow vesicle-specific detection and characterization of size and surface markers. We found significant effects of cell density and conditioning time on both abundance and size distribution of EndoEVs. Additionally, we present detailed information regarding the surface marker display on EVs from different fractions and size ranges. Our data provide crucial relevance for future projects aiming to elucidate EV secretion behavior of endothelial cells. Moreover, we show that the influence of different conditioning parameters on the nature of EndoEVs has to be considered.     

Investigating the co-creation of IT consulting service value: empirical findings of a matched pair analysis

Electronic Markets - Digitalization is increasingly and broadly impacting on companies throughout all industries. To cope with digital transformation, organizations need specific IT skills and...     

Origin of mechanical strain sensitivity of pentacene thin-film transistors

We report on bending strain-induced changes of the charge carrier mobility in pentacene organic thin-film transistors employing a combined investigation of morphological, structural, and electrical properties. The observed drain current variations are reversible if the deformation is below 2%. The morphology and structure of the active pentacene layer is investigated by scanning force microscopy and specular synchrotron X-ray diffraction, which show that bending-stress causes morphological rather than structural changes, modifying essentially the lateral spacing between individual pentacene crystallites. In addition, for deformations >2% the rupture of source and drain gold electrodes is observed. In contrast to the metal electrodes, the modification of the organic layer remains reversible for deformations up to 10%, which suggests the use of soft and flexible electrodes such as graphene or conducting polymers to be beneficial for future strain sensing devices.     

Spiral interferogram analysis

Interference microscopy using spatial Fourier filtering with a vortex phase element leads to interference fringes that are spirals rather than closed rings. Depressions and elevations in the optical thickness of the sample can be distinguished immediately by the sense of rotation of the spirals. This property allows an unambiguous reconstruction of the object's phase profile from one single interferogram. We investigate the theoretical background of "spiral interferometry" and suggest various demodulation techniques based on the processing of one single interferogram or multiple interferograms.     

Radionuclide microscopic diagnostics of the translational mobility of atoms and of the crystal defectiveness, with the crystallization of CaSO4·2H2O from supersaturated aqueous solution as example

The specific features of the behavior and interaction of nonequilibrium defects arising in fluctuation growth of gypsum crystals from aqueous solution and the effect of these defects on the self-diffusion coefficients of the crystallizant atoms were revealed by radionuclide microscopic diagnostics using a pair of tracers (⁴⁵Ca and ³⁵S). In the course of the experiment, the kinetics of the radionuclide transfer from the solution to the solid phase was compared with the mathematical model of the diffusion transfer of radionuclides from a limited volume of the solution into particles of a polydispersed solid and with the pH variation in the course of formation and existence of the solid phase. In the course of gypsum crystal growth, the expanding surface captures the CaOH⁺ and HSO ₄ ^? ions which form nonequilibrium vacancies in the anionic and cationic sublattices. Excess defects interact with each other to form on the crystal surface and in its bulk molecular vacancies, dipolons, or are annealed in the course of aging. Dipolons are responsible for high self-diffusion coefficients of the crystallizant atoms. Perfection of the solid phase leads to a decrease in these quantities by two orders of magnitude.     

Evolution of the snow area index of the subarctic snowpack in central Alaska over a whole season. consequences for the air to snow transfer of pollutants

The detailed physical characteristics of the subarctic snowpack must be known to quantify the exchange of adsorbed pollutants between the atmosphere and the snow cover. For the first time, the combined evolutions of specific surface area (SSA), snow stratigraphy, temperature, and density were monitored throughout winter in central Alaska. We define the snow area index (SAI) as the vertically integrated surface area of snow crystals, and this variable is used to quantify pollutants' adsorption. Intense metamorphism generated by strong temperature gradients formed a thick depth hoar layer with low SSA (90 cm(2) g-1) and density (200 kg m(-3)), resulting in a low SAI. After snowpack buildup in autumn, the winter SAI remained around 1000 m(2)/m(2) of ground, much lower than the SAI of the Arctic snowpack, 2500 m(2) m-(2). With the example of PCBs 28 and 180, we calculate that the subarctic snowpack is a smaller reservoir of adsorbed pollutants than the Arctic snowpack and less efficiently transfers adsorbed pollutants from the atmosphere to ecosystems. The difference is greater for the more volatile PCB 28. With climate change, snowpack structure will be modified, and the snowpack's ability to transfer adsorbed pollutants from the atmosphere to ecosystems may be reduced, especially for the more volatile pollutants.     

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