Group III nitrides are promising materials for light emitting diodes (LEDs). The occurrence of structural defects strongly affects the efficiency of these LEDs. We investigate the optical properties of basal plane stacking faults (BFSs), and the assignment of specific spectral features to distinct defect types by direct correlation of localized emission bands measured by cathodoluminescence in a scanning electron microscope with defects found in high resolution (scanning) transmission electron microscopy and electron beam induced current at identical sample spots. Thus, we are able to model the electronic structure of BSFs addressing I-1, I-2, and E type BSFs in GaN and AlGaN with low Al content. We find hints that BSFs in semipolar AlGaN layers cause local changes of the Al content, which strongly affects the usability of AlGaN as an electron blocking layer in nitride based LEDs.
Background: Among potentially modifiable risk factors for delirium, transfers between wards, hospitals and other facilities have been mentioned with low evidence. TRADE (TRAnsport and DElirium in older people) was set up to investigate i) the impact of transfer and/or discharge on the onset of delirium in older adults and ii) feasibility and acceptance of a developed complex intervention targeting caregiver’s participation during and after hospital discharge or transfer on cognition and the onset of delirium in older adults.
Methods: The study is designed according to the guidelines of the UK Medical Research Council (MRC) for development and evaluation of complex interventions and comprises two steps: development and feasibility/piloting. The development phase includes i) a multicenter observational prospective cohort study to assess delirium incidence and cognitive decline associated with transfer and discharge, ii) a systematic review of the literature, iii) stakeholder focus group interviews and iv) an expert workshop followed by a Delphi survey. Based on this information, a complex intervention to better and systematically involve family caregivers in discharge and transport was developed. The intervention will be tested in a pilot study using a stepped wedge design with a detailed process and health economic evaluation.
The study is conducted at four acute care hospitals in southwest Germany. Primary endpoints are the delirium incidence and cognitive function. Secondary endpoints include prevalence of caregiver companionship, functional decline, cost and cost effectiveness, quality of discharge management and quality of admission management in admitting hospitals or nursing homes. Data will be collected prior to discharge as well as after 3, 7 and 90 days.
Recently, an increasing interest has been devoted to external combustion cycles (e.g. supercritical CO2 Brayton cycles) due to the opportunity to use low quality fuels. Among these, the use of biomass is of particular relevance for its low environmental impact. On the other hand, the combustion of biomass has several critical aspects that might hamper the efficiency of the process, especially in case of solid biomass (woodchip). A detailed experimental analysis of biomass woodchips behavior inside the combustion bed can provide useful information on fuel distribution, combustor loading pattern, fuel segregation and stacking. Unfortunately, a detailed experimental analysis is quite hard to perform due to the harsh environment, the difficulty in setting up a well scaled model of the device (both as geometrical and power sizes) and an efficient particle tracking method. Regarding this last issue, in this study, an optical tracking method to provide information on the main pattern of motion of the fuel inside of a model of biomass fixed bed combustion system is proposed.
Tests were performed without combustion, by inserting the woodchips in the bed through a charging screw. A portion of the fuel has been colored according to its size with negligible modification of the particles mass and dimensions. A digital camera, placed above the bed, was used to constantly capture pictures of the bed surface. The position of the screw during its revolution was correlated to the acquired images. A Matlab tool was developed to detect the movement of the particles on the top of the fuel bed over time (theoretically exposed directly to the flame) by distinguishing the path according to the particle sizes.
The motion of the particles was detected by using a specifically developed procedure which operates in four steps:
1) Image resizing to avoid perspective deformation or orientation variations (a set of reference pins was installed on the test bed and used to have all the images with the same orientation and size)
2) Identification of the particle size by detecting their color
3) Sseparation of the images in sub images according to particle size
4) Detection of particle position and definition of particle centers
5) Calculation of particle motion by comparing the particle center position in subsequent images
The procedure, allowed the detection of the particles preferential pattern as a function of their size and the bed parameters. The results were particularly useful to understand potential inefficiencies of the combustion system due to an uneven woodchips distribution. In addition, the results achieved with the proposed test rig and the adopted methodology can also be used to validate results from Discrete Element Modelling (DEM) simulations.
Agilität scheint das neue „Neu“ zu sein. Was sich hinter diesem Buzz-Word verbirgt, haben Martin Luckmann und Christiane Prange im ersten Teil beschrieben und überdies das Modell „Agile Leadership and Management“ vorgestellt. Im zweiten Teil geht es um eine Konkretisierung am Beispiel der BMW Stiftung Herbert Quandt und ihrer Idee von agiler Leadership. Im Gespräch mit Markus Hipp, dem geschäftsführenden Vorstand der BMW Stiftung, gehen Martin Luckmann und Andreas Müller auf die Suche.
Agilität scheint das neue „Neu“ zu sein. Was sich hinter diesem Buzz-Word verbirgt, haben Martin Luckmann und Christiane Prange im ersten Teil der Serie beschrieben und das Modell „Agile Leadership and Management“ vorgestellt. Im zweiten Teil ging es im Gespräch mit Markus Hipp, dem geschäftsführenden Vorstand der BMW Stiftung Herbert Quandt, um die Konkretisierung agiler Leadership am Beispiel der Transsektoralität. Im dritten Teil geht es nun um eine Konkretisierung am Beispiel der österreichischen Zweite Sparkasse und ihrer Vorstellung von agiler Identity. Im Gespräch mit Günter Benischek, Vorstandsmitglied der Zweite Sparkasse, gehen Martin Luckmann und Andreas Müller wieder auf die Suche.