Development of the Heidelberg Airborne Imaging DOAS Instrument (HAIDI) - A novel remote sensing device for the investigation of two- and three-dimensional trace gas distributions in the troposphere

The investigation of trace gases and related chemical processes in the atmosphere on local and regional scales requires measurement techniques with high spatial resolution and coverage. In the context of this thesis a novel remote sensing device, the Heidelberg Airborne Imaging DOAS Instrument (HAIDI), was developed. HAIDI works on the basis of the well established DOAS method and has the ability to determine horizontal and vertical distributions of several important atmospheric species with a resolution of better than 100 m at high sensitivity. The thesis gives a detailed overview on the operating principle of the instrument and its characteristics. In addition, measurement results of several field campaigns with this instrument are presented, which yielded interesting findings. For instance, BrO/SO2 ratios were measured at Mt. Etna (Italy), showing constant values of 1.4 × 10−4 and 2.0 × 10−4, respectively, along the plume’s centerline on both measurement days (observed plume ages: 2–34 min), but an increase by a factor of two to three towards the edges of the plume. Moreover, a temporal change in the BrO/SO2 ratio was observed prior to the culmination of a paroxysm. The measurements are also one of the first to show spatial resolved OClO/SO2 and OClO/BrO ratios in the plume of Mt. Etna. Further measurements were performed near Indianapolis (Indiana, USA) and Barrow (Alaska, USA) to investigate the spatial distribution of NO2 over polluted urban areas as well as the occurrence of “bromine explosion” events during boundary layer ozone depletion in polar regions. The data allow to characterize the spatial distribution of BrO and thus give insight into possible bromine sources

The Role of Open Lead Interactions in Atmospheric Ozone Variability Between Arctic Coastal and Inland Sites

Boundary layer atmospheric ozone depletion events (ODEs) are commonly observed across polar sea ice regions following polar sunrise. During March-April 2005 in Alaska, the coastal site of Barrow and inland site of Atqasuk experienced ODEs (O3 \u3c 10 nmol mol-1) concurrently for 31% of the observations, consistent with large spatial scale ozone depletion. However, 7% of the time ODEs were exclusively observed inland at Atqasuk. This phenomenon also occurred during one of nine flights during the BRomine, Ozone, and Mercury EXperiment (BROMEX), when atmospheric vertical profiles at both sites showed near-surface ozone depletion only at Atqasuk on 28 March 2012. Concurrent in-flight BrO measurements made using nadir scanning differential optical absorption spectroscopy (DOAS) showed the differences in ozone vertical profiles at these two sites could not be attributed to differences in locally occurring halogen chemistry. During both studies, backward air mass trajectories showed that the Barrow air masses observed had interacted with open sea ice leads, causing increased vertical mixing and recovery of ozone at Barrow and not Atqasuk, where the air masses only interacted with tundra and consolidated sea ice. These observations suggest that, while it is typical for coastal and inland sites to have similar ozone conditions, open leads may cause heterogeneity in the chemical composition of the springtime Arctic boundary layer over coastal and inland areas adjacent to sea ice regions

Comorbidity and dementia : a mixed method study on improving healthcare for people with dementia (CoDem)

© Queen’s Printer and Controller of HMSO 2016. This work was produced by Bunn et al. under the terms of a commissioning contract issued by the Secretary of State for Health. This issue may be freely reproduced for the purposes of private research and study and extracts (or indeed, the full report) may be included in professional journals provided that suitable acknowledgement is made and the reproduction is not associated with any form of advertising. Applications for commercial reproduction should be addressed to: NIHR Journals Library, National Institute for Health Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UKAmong people living with dementia (PLWD) there is a high prevalence of comorbid medical conditions but little is known about the effects of comorbidity on processes and quality of care and patient needs or how services are adapting to address the particular needs of this population. To explore the impact of dementia on access to non-dementia services and identify ways of improving the integration of services for this population

Impact of clinical phenotypes on management and outcomes in European atrial fibrillation patients: a report from the ESC-EHRA EURObservational Research Programme in AF (EORP-AF) General Long-Term Registry

Background: Epidemiological studies in atrial fibrillation (AF) illustrate that clinical complexity increase the risk of major adverse outcomes. We aimed to describe European AF patients\u2019 clinical phenotypes and analyse the differential clinical course. Methods: We performed a hierarchical cluster analysis based on Ward\u2019s Method and Squared Euclidean Distance using 22 clinical binary variables, identifying the optimal number of clusters. We investigated differences in clinical management, use of healthcare resources and outcomes in a cohort of European AF patients from a Europe-wide observational registry. Results: A total of 9363 were available for this analysis. We identified three clusters: Cluster 1 (n = 3634; 38.8%) characterized by older patients and prevalent non-cardiac comorbidities; Cluster 2 (n = 2774; 29.6%) characterized by younger patients with low prevalence of comorbidities; Cluster 3 (n = 2955;31.6%) characterized by patients\u2019 prevalent cardiovascular risk factors/comorbidities. Over a mean follow-up of 22.5 months, Cluster 3 had the highest rate of cardiovascular events, all-cause death, and the composite outcome (combining the previous two) compared to Cluster 1 and Cluster 2 (all P <.001). An adjusted Cox regression showed that compared to Cluster 2, Cluster 3 (hazard ratio (HR) 2.87, 95% confidence interval (CI) 2.27\u20133.62; HR 3.42, 95%CI 2.72\u20134.31; HR 2.79, 95%CI 2.32\u20133.35), and Cluster 1 (HR 1.88, 95%CI 1.48\u20132.38; HR 2.50, 95%CI 1.98\u20133.15; HR 2.09, 95%CI 1.74\u20132.51) reported a higher risk for the three outcomes respectively. Conclusions: In European AF patients, three main clusters were identified, differentiated by differential presence of comorbidities. Both non-cardiac and cardiac comorbidities clusters were found to be associated with an increased risk of major adverse outcomes

Flow Path and Interaction Analysis in a Hydrogen Transpiration Cooled Scramjet Model Combustor

Cooling experiments are performed by the DLR Institute of Space Propulsion, applying a transpiration cooling system to a scramjet model combustion chamber. Hydrogen coolant is injected through different porous wall samples made of sintered stainless steel into a Mach 2.5 hot gas main flow. Different inlet conditions as well as the response of the transpiration cooling to a shock impingement caused by a 9.3° half wedge at different lateral positions are investigated by means of Background Oriented Schlieren (BOS). Results show good transpiration cooling efficiency which is governed by the impinging shock and its position. Limitations and encountered flow phenomena of this cooling approach are also discusse

Shock-Boundary Layer Interaction Phenomena in a Hydrogen Transpiration Cooled Supersonic Combustion Ramjet (Scramjet)

Cooling experiments are performed by the DLR Institute of Space Propulsion, applying a transpiration cooling system to a scramjet model combustion chamber. Hydrogen coolant is injected through different porous wall samples made of sintered stainless steel into a Mach 2.5 hot gas main flow. Different inlet conditions, as well as the response of the transpiration cooling to a shock impingement caused by a 9.3° half wedge at different lateral positions, are investigated by means of Background Oriented Schlieren (BOS). Results show good transpiration cooling efficiency, which is governed by the impinging shock and its position. Limitations of this cooling approach and the encountered flow phenomena are also discussed

Experiments on Transpiration Cooling in a Model Scramjet Combustor Using Background Oriented Schlieren (BOS)

The Institute of Space Propulsion of the German Aerospace Center (DLR) has developed and set up a research test bench to investigate the applicability of transpiration cooling systems to scramjets and to examine the resulting phenomena in the supersonic flow. It consists of a chemical hydrogen / oxygen air vitiator with attached Scramjet model combustion chamber with an optional half wedge shaped shock generator. The used porous media consists of high temperature resistant stainless steel and Inconel with different porosities. Gaseous nitrogen and gaseous hydrogen were used as coolant with different pre-pressures. Optical access allows the use of a Schlieren system and Background Oriented Schlieren (BOS) for flow investigations. Phenomena such as hot spots on the porous wall, inefficient cooling and shock-boundary layer interaction (SBLI) were observed in the experiments. With the BOS system thickening of the boundary layer / boundary layer separation was demonstrated. Furthermore, the development of shock trains forced by the introduction of a secondary coolant flow can be illustrated, leading to an increased physical blockage up to the choking case. This publication summarizes the SBLI results gained by application of Background Oriented Schlieren (BOS) setup and compares them with results obtained by the help of a classic Schlieren setup. BOS emerged in the experiments to be less affected by changes in the refractive index of the quartz glass windows due to strong heating compared to the classic Schlieren method. Challenges in optimizing the BOS systems’ performance and subsequent changes in the test setup are discussed

Experimental Flow Path Analysis of a Hydrogen Transpiration Cooled Model Scramjet Combustor

Cooling experiments are performed by DLR Institute of Space Propulsion, applying a transpiration cooling system to a scramjet model combustion chamber. Hydrogen coolant is injected through different porous wall samples made of sintered stainless steel into a Mach 2.5 hot gas main flow. Different inlet conditions as well as the response of the transpiration cooling to a shock impingement caused by a 9.3° half wedge at different lateral positions are investigated. Results show good transpiration cooling efficiency which is governed by the impinging shock and its position. Limitations of this cooling approach are also discussed

Prediction of Subscale Rocket Engine Acoustic Emissions Using CAA Hybrid Methods

This work presents the results of a numerical study predicting the acoustical emissions induced by the supersonic jets of two different types of nozzle using a CAA (Computational Aeroacoustics) hybrid method. The two types of nozzles studied are a Truncated Ideal Contour (TIC) and a Thrust Optimized Parabola (TOP). To achieve this goal two test series were conducted with the TIC and the TOP nozzle. The results show that the quality of the results depend on the direction in which it is measured. The Agreement between experiments and simulation are good in the areas where the underlying model expects it

Hot Firing of a Film-Cooled ALM Dual-Bell Nozzle

The transition behaviour of a film-cooled dual-bell nozzle was studied experimentally at DLR test facility P8, under representative hot-flow conditions. Independent of the adjusted cooling film mass flow, all operation mode transitions were stable