Public Policy and Success of Business Start-ups in Germany

In this paper, we evaluate the success of publicly supported business start-ups by comparing the outcomes of various support measures. Our question is: do business starter get what they need? Since we do not know the needs of the founders we analyse (1) who received which kind of support (financial support, individual coaching, general information) and (2) which kind of support is successful for whom with regard to his/her job history (employed, unemployed or being not part of the job market). While start-up measures possibly could aim at different kinds of eff ects, our focus is on the effect on subsequent firm growth. The analysis is based on a survey conducted in 2005. The sample was drawn from a highly heterogeneous population of business start-ups. By using propensity score exact matching for success measurement we try to capture those differences.Business start-ups, public policy, public support, matching

Current trends in CMC research & development across DLR’s technology programs

Please click Additional Files below to see the full abstract

Unidirectional fibre reinforced geopolymer matrix composites

Geopolymers have been suggested in the literature as matrix materials for fibre reinforced composites due to a unique combination of low-temperature synthesis and high temperature stability. This study investigated several key aspects of fibre reinforced geopolymer matrix composites in order to improve the basic knowledge of these materials. It was demonstrated that geopolymer matrix composites show great potential as fire-resistant materials for near room temperature applications. In particular, basalt fibre composites were of great interest due to their comparatively low cost and good mechanical performance. Microstructural investigations indicated that basalt fibres can potentially be used in geopolymer matrices up to 600°C. However, the success of the application of geopolymer matrix composites at higher temperatures is seen as critical and depends on further development of suitable matrices. Several compositions within a sodium-metahalloysite model matrix system were evaluated in order to identify a suitable formulation for composite fabrication. An average compressive strength of ~ 79 MPa and flexural strength and modulus of ~ 10 MPa and 8.5 GPa, respectively, were achieved for the best batch of the main matrix composition. By optimising the matrix composition, the mechanical properties could be significantly improved, achieving an extremely high maximum compressive strength value of 145 MPa. Issues with reproducibility and the influence of various aspects of the fabrication process are discussed. The room temperature flexural properties of unidirectional fibre reinforced composite bars with basalt, carbon and alumina fibres were investigated. Besides the fibre type, the effects of several other parameters including fibre sizing, matrix strength, span-to-depth ratio and specimen dimensions on the flexural properties and the failure behaviour of the composites were studied. Significant improvements to the mechanical properties were achieved with all fibre types. However, the mechanical behaviour was highly influenced by the elastic modulus of the fibre. Furthermore, it was shown that the composite properties were affected by the overall sample dimensions, the testing span and the mixing time of the geopolymer binder. The alumina fibre composites achieved the highest flexural stress with a maximum value of 470 MPa and a fibre content of ~ 30 vol.-%. Basalt and carbon fibre composites showed maximum flexural strength values around 200 MPa. Although all composite types displayed considerable post-fracture strength, only the basalt composites failed in tensile mode. The applicability of the weak matrix composites (WMC) concept to describe the mechanical behaviour of geopolymer matrix composites was discussed. The fibre-matrix interactions were analysed between room temperature and 1000°C by means of electron microscopy, EDS and x-ray diffraction. All fibres were found to be chemically stable under the highly alkaline conditions of the geopolymer synthesis and showed no significant reaction with the geopolymer matrix at room temperature. The results indicate that basalt fibre composites may be used up to 600°C without significant degradation of the fibre. The heating of the carbon fibre composites to 600°C had drastic effect on the strength and integrity of the composite, in particular, when using sized carbon fibres. The alumina fibres showed good wetting and bonding behaviour but otherwise little reaction with the matrix even after heating to 1000°C

Critical processing parameters for wound oxide CMC and their effect on material properties

Fibre reinforced all oxide ceramic matrix composites (oxCMC) have made significant advancements over the past 20 years and have found their way into a growing number of industrial applications. However, the material properties and quality vary considerably and depend strongly on the manufacturing process and respective processing parameters. With regards to industrial production capability, filament winding is the most automated and state-of-the-art fabrication technology for oxCMC today, in particular for rotational symmetric designs and components. Nevertheless, there is considerable potential to improve material properties and quality by technological optimization of critical processing parameters to meet the growing demands and requirements of future applications. Several key processing parameters for filament winding of oxide CMC were identified and their effect on the overall processability and resulting material properties will be presented, demonstrating a significant improvement of material homogeneity and reproducibility as well as an increase in bending strength by around 30%

The analysis of cadmium and its oxide by atomic-emission and massspectrometry with inductive coupled plasma

In present work, the multielemental methods for the cadmium and its oxide analysis by atomicemission and mass-spectrometry with inductively coupled plasma (AES-ICP and MS-ICP) have been proposed. The influence of the matrix concentration and the power supplied to the plasma on the analytic signals of the impurities has been studied, analytical lines and isotopes of the determined elements have been chosen. We have made the accuracy estimation of the developed techniques, the ICP-AES technique allows to determine 41 analytes with detection limits in the range from n•10{-7} to n•10{-4} % wt, ICP-MS technique allows to determine 58 elements with detection limits on the level n •10{-8}-n•10{-3} % wt Введение. Кадмий высокой чистоты является прекурсором

Figures of Merit for Photocatalysis: Comparison of NiO/La-NaTaO3 and Synechocystis sp. PCC 6803 as a Semiconductor and a Bio-Photocatalyst for Water Splitting

While photocatalysis is considered a promising sustainable technology in the field of heterogeneous catalysis as well as biocatalysis, figures of merit (FOM) for comparing catalytic performance, especially between disciplines, are not well established. Here, photocatalytic water splitting was conducted using a semiconductor (NiO/La-NaTaO3) and a bio-photocatalyst (Synechocystis sp. PCC 6803) in the same setup under similar reaction conditions, eliminating the often ill-defined influence of the setup on the FOMs obtained. Comparing the results enables the critical evaluation of existing FOMs and a quantitative comparison of both photocatalytic systems. A single FOM is insufficient to compare the photocatalysts, instead a combination of multiple FOMs (reaction rate, photocatalytic space time yield and a redefined apparent quantum yield) is superior for assessing a variety of photocatalytic systems