Two particle enhanced nano Raman microscopy and spectroscopy

The distance- and polarization-dependent near-field enhancement of two coupling metal nanoparticles (MNPs) is analyzed by means of the novel scanning particle enhanced Raman spectroscopy (SPRM) technique. In contrast to single MNP Raman experiments, the near-field coupling between two dissimilar MNPs as followed here leads to a Raman hot spot yielding an extra enhancement factor of 17.6 and 20, as proven here both in experiment and in theory. Three-dimensional electric field calculations for our two-particle arrangements were performed using the semianalytical multiple-multipole method. An excellent agreement is found to our experiments, in which we inspect the interaction between a "scanning" 30 nm gold MNP (Au30) and a "fixed" 80 nm Au MNP (Au80). The Au80 MNP is attached to the apex of an optical fiber manipulator and exposed to the Gaussian focus of a high NA = 1.45 objective at lambda = 532 nm. A monolayer of 1-octanethiol molecules covering the Au80 MNP serves as the electric field prober when scanning the Au30 MNP through the optical focus. This constellation allows recording the Raman signatures from a very low number of well-confined molecules. Moreover, also the spectral and spatial dependence could be explored with a superb sensitivity and very low integration time.     

Discontinuous profile grinding of multi-phase,case-hardened gears with improved load-carrying capacity

Highly-loaded transmission components like gears are case hardened for most applications to reach a load adapted strength. The surface layer microstructure as a function of heat treatment decisively determines the achievable load-bearing properties of the component as well as the technological limits of gear grinding. Against this background, this paper deals with the machinability (discontinuous profile grinding) of differently (carburizing and carbonitriding) case-hardened gears with various multi-phase microstructures and improved load-carrying capacity. Therefore, effects of different material phases, precipitates and their distribution in the surface layer on the gear-grinding process will be discussed.     

FLATCON® CPV module with 36.7% efficiency equipped with four‐junction solar cells

In this paper we present the application of high efficiency four‐junction solar cells using SOITEC bonding technology under a Fresnel lens optic and in a FLATCON®‐type CPV module. We demonstrate very high performance. The measurement of a sub‐module, consisting of a four‐junction solar cell adjusted under a single Fresnel lens, showed an efficiency of 38.9%. An 829.6 cm² sized FLATCON®‐type CPV module yielded in an efficiency of 35.0% and 36.7% at CSOC and CSTC, respectively. Thus, both, the sub‐module and the CPV module showed record values, which prove the usefulness of high efficiency four‐junction solar cells in CPV applications. Copyright © 2014 John Wiley & Sons, Ltd.     

Development of KSTAR ECE imaging system for measurement of temperature fluctuations and edge density fluctuations

The ECE imaging (ECEI) diagnostic tested on the TEXTOR tokamak revealed the sawtooth reconnection physics in unprecedented detail, including the first observation of high-field-side crash and collective heat transport [H. K. Park, N. C. Luhmann, Jr., A. J. H. Donne? et al., Phys. Rev. Lett. 96, 195003 (2006)]. An improved ECEI system capable of visualizing both high- and low-field sides simultaneously with considerably better spatial coverage has been developed for the KSTAR tokamak in order to capture the full picture of core MHD dynamics. Direct 2D imaging of other MHD phenomena such as tearing modes, edge localized modes, and even Alfve?n eigenmodes is expected to be feasible. Use of ECE images of the optically thin edge region to recover 2D electron density changes during L/H mode transitions is also envisioned, providing powerful information about the underlying physics. The influence of density fluctuations on optically thin ECE is discussed.     

The influence of extensive vegetated roofs on runoff water quality

The influence of extensive sedum-moss vegetated roofs on runoff water quality was studied for four full scale installations located in southern Sweden. The aim of the study was to ascertain whether the vegetated roof behaves as a sink or a source of pollutants and whether the age of a vegetated roof influences runoff quality. The runoff quality from vegetated roofs was also compared with the runoff quality from non-vegetated roofs located in study areas. The following metals and nutrients were investigated: Cd, Cr, Cu, Fe, K, Mn, Pb, Zn, NO3-N, NH4-N, Tot-N, PO4-P, and Tot-P. The results show that, with the exception of nitrogen, vegetated roofs behave as source of contaminants. While in lower concentrations than normally found in urban runoff, some metals appear in concentrations that would correspond to moderately polluted natural water. Nitrate nitrogen is retained by the vegetation or soil or both. Apart from the oldest, the studied vegetated roofs contribute phosphate phosphorus to the runoff. The maintenance of the vegetation systems on the roofs has to be carefully designed in order to avoid storm-water contamination; for instance, the use of easily dissolvable fertilizers should be avoided.     

Institutions vs. ‘first‐nature’ geography: What drives economic growth in Europe's regions?

The debate on whether institutions or geography prevail in driving economic growth has been rife (e.g., Sachs 2003 vs. Rodrik et al. 2004). Most of the empirical analyses delving into this debate have focused on world countries, whose geographical and institutional conditions differ widely. Subnational analyses considering groups of countries with, in principle, more similar institutional and geographical conditions have been limited and tended to highlight that geography is more important than institutions at subnational level. This paper aims to address whether this is the case by investigating how differences in institutional and ‘first‐nature’ geographical conditions have affected economic growth in Europe's regions in the period 1995–2009. In the analysis we use a newly developed dataset including regional quality of government indicators and geographical characteristics and employ two‐stage least squares (2SLS) and instrumental variables‐generalized method of moments (IV‐GMM) estimation techniques with a number of regional historical variables as instruments. Our results indicate that at a regional level in Europe institutions rule. Regional institutional conditions – and, particularly, government effectiveness and the fight against corruption – play an important role in shaping regional economic growth prospects. This does not imply, however, that geography is irrelevant. There is evidence of geographical factors affecting regional growth, although their impact is dwarfed by the overriding influence of institutions.     

Quellen und Vorkommen kurzkettiger Alkylphenole (SCAP)

A literature research and own data on Short Chain Alkyl Phenols (SCAP) in the environment indicate that treatment of solid fossil fuel materials and the production of chemicals from various industries have common potenzial anthropogenic sources of SCAP compounds in the environment. Potenzial natural sources of SCAP in the environment are solely from petroliferous rocks. A wide range of SCAP applications for different industries is summarized here briefly. Many process-based inputs to the environment have been identified. Contaminations have specific “fingerprints”, (unique types of SCAP compound occurrences). This enables the identification of SCAP sources. Furthermore, unique environmental properties among the variety of SCAP compounds, facilitates characterisation of contaminated sites. Knowledge of the unique SCAP “fingerprints” in conjunction with the environmentally predictable relationships of the various SCAP compounds is the basis for the use of these substances in process and flow characterisation within aquifers.     

Hydraulische Leitfähigkeiten von Sedimentwürfeln vor und nach einem gefrorenen Zustand

To study flow and transport processes in heterogeneous porous media, frozen sediment cubes that were assembled in sandbox experiments may represent a viable procedure. In this investigation, it was important to find out how flow and transport properties would be modified by sediment freezing. In this study, a medium sand, a coarse sand and a fine gravel were investigated to find out to what extent the hydraulic conductivities might change before and after freezing. For this purpose, a cubic Darcy-cell was developed. The results of the study show that it is possible to produce 10?×?10?×?10 cm frozen sediment cubes with the presented apparatus. The study also suggests that freezing and subsequent thawing only caused small changes in hydraulic conductivity of the investigated sediments.