Large droplet impact on water layers

The impact of large droplets onto an otherwise undisturbed layer of water is considered. The work, which is motivated primarily with regard to aircraft icing, is to try and help understand the role of splashing on the formation of ice on a wing, in particular for large droplets where splash appears, to have a significant effect. Analytical and numerical approaches are used to investigate a single droplet impact onto a water layer. The flow for small times after impact is determined analytically, for both direct and oblique impacts. The impact is also examined numerically using the volume of fluid (VOF) method. At small times there are promising comparisons between the numerical results, the analytical solution and experimental work capturing the ejector sheet. At larger times there is qualitative agreement with experiments and related simulations. Various cases are considered, varying the droplet size to layer depth ratio, including surface roughness, droplet distortion and air effects. The amount of fluid splashed by such an impact is examined and is found to increase with droplet size and to be significantly influenced by surface roughness. The makeup of the splash is also considered, tracking the incoming fluid, and the splash is found to consist mostly of fluid originating in the layer

Droplet impact on a thin fluid layer

The initial stages of high-velocity droplet impact on a shallow water layer are described, with special emphasis given to the spray jet mechanics. Four stages of impact are delineated, with appropriate scalings, and the successively more important influence of the base is analysed. In particular, there is a finite time before which part of the water in the layer remains under the droplet and after which all of the layer is ejected in the splash jet

Modelling Electronic Circuit Failures using a Xilinx FPGA System

FPGAs are a ubiquitous electronic component utilised in a wide range of electronic systems across many industries. Almost all modern FPGAs employ SRAM based configuration memory elements which are susceptible to radiation induced soft errors. In high altitude and space applications, as well as in the nuclear and defence industries, such circuits must operate reliably in radiation-rich environments. A range of soft error mitigation techniques have been proposed but testing and qualification of new fault tolerant circuits can be an expensive and time consuming process. A novel method for simulating radiation-induced soft errors is presented that operates entirely within a laboratory environment and requires no hazardous exposure to radiation or expensive airborne test rigs. A system utilising modular redundancy is then implemented and tested under the new method. The test system is further demonstrated in conjunction with a software flight simulator to test single electronic modules in the context of active service on board a passenger aircraft and the effects of failure under radiation induced soft errors are observed. Our research proposes a test regime in which design strategies for self-healing circuits can be compared and demonstrated to work

Industrial Gas Turbine Performance Measurement

PaperPg. 59-66.An accurate assessment of the performance of an industrial gas turbine, in service, has been the goal of many test programs initiated by users and manufacturers alike. The rewards of such programs often are quite skimpy because of the difficulty of obtaining an accurate measurement of some of the basic engine parameters necessary for this assessment, power output being one of the more obstinate parameters. The author has been indirectly involved, during the past two and a half years, in devising and carrying out factory and field performance tests which had, as a primary purpose, a lessening of the uncertainties involved in measuring and interpreting these parameters. Where possible, direct measurement of power output, turbine inlet temperature and air mass flow was utilized for comparison with other, less direct methods of measurement. Those installations in which electrical power is the end product are the most compliant, since the electrical generator driven by the turbine provides an accurate determination of power output. On the other hand, a load consisting of a pump or compressor presents a much less accurately determined picture of power output. It is those installations having the latter type of loading device which have been the subject of the investigations reported in this paper

Integrated Project Support Study Group : findings

The challenges of the LHC project have lead CERN to produce a comprehensive set of project management tools covering engineering data management, project scheduling and costing, event management and document management. Each of these tools represents a significant and world-recognised advance in their respective domains. Reviewing the offering on the eve of LHC commissioning one can identify three major challenges: 1. How to integrate the tools to provide a uniform and integrated full-product lifecycle solution 2. How to evolve the functionality in certain areas to address weaknesses identified with our experience in constructing the LHC and integrate emerging industry best practices 3. How to coherently package the offering not just for future projects in CERN, but moreover in the context of providing a centre of excellence for worldwide collaboration in future HEP projects

Reproducibility of cardiac 31P MRS at 7 T

Synopsis Cardiac PCr/ATP ratios measured by P MRS change in cardiovascular disease giving them value as a biomarker. We scanned 13 healthy volunteers at 7T, assessing their PCr/ATP with 6 ½ min P CSI scans. These data have better reproducibility than a 30min 3T protocol previously published by our centre. Repeated PCr/ATP measurements from subjects in this study were not significantly (P=0.83) different. Measurements were significantly different (P<0.001) from DCM patient data acquired in a previous 7T study using the same coil and pulse sequence. This data will allow us to plan future 7T P-MRS clinical studies.Funded by a Sir Henry Dale Fellowship from the Wellcome Trust and the Royal Society (Grant No. 098436/Z/12/Z). JE receives a DPhil (PhD) studentship from the Medical Research Council (UK)

3D printing the future: scenarios for supply chains reviewed

Purpose: The aim of this paper is to evaluate existing scenarios for 3D Printing in order to identify the “white space” where future opportunities have not been proposed or developed to date. Based around aspects of order penetration points, geographical scope and type of manufacturing, these gaps are identified. Design/methodology/approach: A structured literature review has been carried out on both academic and trade publications. As of the end of May 2016, this identified 128 relevant articles containing 201 future scenarios. Coding these against aspects of existing manufacturing and supply chain theory has led to the development of a framework for identify “white space” in existing thinking. Findings: The coding shows that existing future scenarios are particularly concentrated on job shop applications and pull based supply chain processes, although there are fewer constraints on geographical scope. Five distinct areas of “white space” are proposed, reflecting various opportunities for future 3DP supply chain development. Research limitations: Being a structured literature review, there are potentially articles not identified through the search criteria used. The nature of the findings is also dependent upon the coding criteria selected. However, these are theoretically derived and reflect important aspect of strategic supply chain management. Practical implications: Practitioners may wish to explore the development of business models within the “white space” areas. Originality/value: Currently, existing future 3DP scenarios are scattered over a wide, multi-disciplinary literature base. By providing a consolidated view of these scenarios, it is possible to identify gaps in current thinking. These gaps are multidisciplinary in nature and represent opportunities for both academics and practitioners to exploit