High-Performance research for High-tech materials:1. Degussa’s Science-to-Business Center Nanotronics, 2. Four percent for the future

High-performance research for High-tech materials is an article about Degussa AG´s research efforts and strategy. Degussa AG, Germany, has decided to increase investment in research and development significantly—from 3.1 percent of sales revenue in 2004 to 4 percent by 2007. How is the firm going to achieve this goal? The paper is divided into two parts. First Dr. Andreas Gutsch gives newest insight into the Science-to-Business Center Nanotronics. Second an interview with Prof. Dr. Michael Dröscher answers questions about research strategy and project portfolio management

Gestión de bosques mixtos de pino y roble en escenarios de incertidumbre climática

The process-based forest growth model 4C (FORESEE - FORESt Ecosystems in a Changing Environment) was used to analyze the growth of a mixed oak-pine stand [Quercus petraea (Mattuschka) Liebl., Pinus sylvestris L.]. The oak-pine stand is typical for the ongoing forest transformation in the north-eastern lowlands. The pine and the oak trees are 104 and 9 years old, respectively. Three different management scenarios (A, B, C) with different thinning grades and a thinning interval of five years were simulated. Every management scenario was simulated under three different climate scenarios (0K, 2K, 3K) compiled by the regional statistical climate model STAR 2.0 (PIK). For each climate scenario 100 different realisations were generated. The realisations of the climate scenarios encompass the period 2036-2060 and exhibit an increase of mean annual temperature of zero, two and three Kelvin until 2060, respectively. We selected 9 model outputs concerning biomass, growth and harvest which were aggregated to a single total performance index (TPI). The TPI was used to assess the management scenarios with regard to three management objectives (carbon sequestration, intermediate, timber yield) under climate change until 2060. We found out that management scenario A led to the highest TPI concerning the carbon sequestration objective and management scenario C performed best concerning the two other objectives. The analysis of variance in the growth related model outputs showed an increase of climate uncertainty with increasing climate warming. Interestingly, the increase of climate induced uncertainty is much higher from 2 to 3 K than from 0 to 2 K.Se ha utilizado un modelo forestal basado en procesos denominado 4C (FORESEE - FORESt Ecosystems in a Changing Environment) para analizar el crecimiento de un masa forestal con mezcla de Quercus petraea y Pinus sylvestris. Ésta es una mezcla típica en las áreas de transformación forestal en las zonas bajas del noreste de Alemania. Los pinos y los robles tienen una edad de 104 y 9 años respectivamente. Se simularon tres escenarios diferentes de manejo (A, B, C) con diferentes grados de claras e intervalos de clara de 5 años. Cada escenario de manejo fue simulado bajo tres escenarios climáticos (0K, 2K, 3K) los cuales se calcularon por el modelo regional climático estadístico STAR 2.0 (PIK). Se generaron 100 diferentes realizaciones para cada escenario climático. Las realizaciones incluyen el período 2036-2060 y presentan un aumento de la temperatura anual de cero, dos y tres grados Kelvin hasta el año 2060, respectivamente. Seleccionamos 9 salidas del modelo relacionadas con la biomasa, crecimiento y rendimiento que se combinaron en un único índice de rendimiento total (TPI, total performance index). El TPI fue analizado para investigar los escenarios de manejo con respecto a tres objetivos de manejo (secuestro de carbono, máximo rendimiento maderero, y un escenario intermedio a ambos) bajo la influencia de cambio climático hasta el año 2060. Nuestros resultados indican que el escenario A muestra el TPI más alto con respecto al secuestro de carbono, y el escenario C tuvo el mejor resultado respecto a los otros dos objetivos. El análisis de varianza en las salidas relativas al crecimiento mostró que mientras más evoluciona el calentamiento global, más crece la incertidumbre climática. Cabe destacar que el aumento de la incertidumbre inducida por el clima es mucho mayor al aumentar de 2 a 3 K que de 0 a 2 K

Uncertainty of biomass contributions from agriculture and forestry to renewable energy resources under climate change

In the future, Germany's land-use policies and the impacts of climate change on yields will affect the amount of biomass available for energy production. We used recent published data on biomass potentials in the federal states of Germany to assess the uncertainty caused by climate change effects in the potential supply of biomass available for energy production. In this study we selected three climate scenarios representing the maximum, mean and minimum temperature increase for Germany out of 21 CMIP5-projections driven by the Representative Concentration Pathways (RCP) 8.5 scenario. Each of the three selected projections was downscaled using the regional statistical climate model STARS. We analysed the yield changes of four biomass feedstock crops (forest, short-rotation coppices (SRC), cereal straw (winter wheat) and energy maize) for the period 2031–2060 in comparison to 1981–2010. The mean annual yield changes of energy wood from forest and short-rotation coppices were modelled using the process-based forest growth model 4C. The yield changes of winter wheat and energy maize from agricultural production were simulated with the statistical yield model IRMA. Germany's annual biomass potential of 1500 PJ varies between minus 5 % and plus 8 % depending on the climate scenario realisation. Assuming that 1500 PJ of biomass utilisation can be achieved, climate change effects of minus 75 (5 %) PJ or plus 120 (8 %) PJ do not impede overall bioenergy targets of 1287 PJ in 2020 and 1534 PJ in 2050. In five federal states the climate scenarios lead to decreasing yields of energy maize and winter wheat. Impacts of climate scenarios on forest yields are mainly positive and show both positive and negative effects on yields of SRC

Sphericity and roundness computation for particles using the extreme vertices model

Shape is a property studied for many kinds of particles. Among shape parameters, sphericity and roundness indices had been largely studied to understand several processes. Some of these indices are based on length measurements of the particle obtained from its oriented bounding box (OBB). In this paper we follow a discrete approach based on Extreme Vertices Model and devise new methods to compute the OBB and the mentioned indices. We apply these methods to synthetic sedimentary rocks and to a real dataset of silicon nanocrystals (Si NC) to analyze the obtained results and compare them with those obtained with a classical voxel model.Peer ReviewedPostprint (author's final draft

Optical emission from Si O2 -embedded silicon nanocrystals: A high-pressure Raman and photoluminescence study

© 2015 American Physical Society. We investigate the optical properties of high-quality Si nanocrystals (NCs)/SiO2 multilayers under high hydrostatic pressure with Raman scattering and photoluminescence (PL) measurements. The aim of our study is to shed light on the origin of the optical emission of the Si NCs/SiO2. The Si NCs were produced by chemical-vapor deposition of Si-rich oxynitride (SRON)/SiO2 multilayers with 5- and 4-nm SRON layer thicknesses on fused silica substrates and subsequent annealing at 1150°C, which resulted in the precipitation of Si NCs with an average size of 4.1 and 3.3 nm, respectively. From the pressure dependence of the Raman spectra we extract a phonon pressure coefficient of 8.5±0.3cm-1/GPa in both samples, notably higher than that of bulk Si(5.1cm-1/GPa). This result is ascribed to a strong pressure amplification effect due to the larger compressibility of the SiO2 matrix. In turn, the PL spectra exhibit two markedly different contributions: a higher-energy band that redshifts with pressure, and a lower-energy band which barely depends on pressure and which can be attributed to defect-related emission. The pressure coefficients of the higher-energy contribution are (-27±6) and (-35±8)meV/GPa for the Si NCs with a size of 4.1 and 3.3 nm, respectively. These values are sizably higher than those of bulk Si(-14meV/GPa). When the pressure amplification effect observed by Raman scattering is incorporated into the analysis of the PL spectra, it can be concluded that the pressure behavior of the high-energy PL band is consistent with that of the indirect transition of Si and, therefore, with the quantum-confined model for the emission of the Si NCs.Work supported by the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement No. 245977 (project NASCEnT). Financial support by the Spanish Government through projects LEOMIS (TEC2012-38540-C02-01) and MAT2012-38664-C02-02 is also acknowledgedPeer Reviewe

Observing the morphology of single-layered embedded silicon nanocrystals by using temperature-stable TEM membranes

We use high-temperature-stable silicon nitride membranes to investigate single layers of silicon nanocrystal ensembles by energy filtered transmission electron microscopy. The silicon nanocrystals are prepared from the precipitation of a silicon-rich oxynitride layer sandwiched between two SiO$_{2}$ diffusion barriers and subjected to a high-temperature annealing. We find that such single layers are very sensitive to the annealing parameters and may lead to a significant loss of excess silicon. In addition, these ultrathin layers suffer from significant electron beam damage that needs to be minimized in order to image the pristine sample morphology. Finally we demonstrate how the silicon nanocrystal size distribution develops from a broad to a narrow log-normal distribution, when the initial precipitation layer thickness and stoichiometry are below a critical value

Determination of shape and sphericity of silicon quantum dots imaged by EFTEM-tomography

The shape of size-controlled silicon nanocrystals (Si NCs) embedded in SiO2 is investigated by tomographic energy-filtered transmission electron microscopy (EFTEM). The sphericity of the quantum dots is determined by computational analyses. In contrast to other fabrication methods, we demonstrate that the NCs in superlattices are non-agglomerated, individual clusters with slightly oblate spheroidal shape. This allows for low surface-to-volume ratios and thereby low non-radiative defect densities as required by optoelectronic or sensing applications. A near-spherical shape is also a prerequisite for the direct comparison of Si quantum dots (QDs) with theoretical simulationsPeer ReviewedPostprint (author's final draft