Systems Challenges for Hypersonic Vehicles

This paper examines the system challenges posed by fully reusable hypersonic cruise airplanes and access to space vehicles. Hydrocarbon and hydrogen fueled airplanes are considered with cruise speeds of Mach 5 and 10, respectively. The access to space matrix is examined. Airbreathing and rocket powered, single- and two-stage vehicles are considered. Reference vehicle architectures are presented. Major systems/subsystems challenges are described. Advanced, enhancing systems concepts as well as common system technologies are discussed

Treatment of septage in sludge drying reed beds: a case study on pilot-scale beds

International audienceFrench legislation requires, the control of private on-site sanitation systems by local authorities. This will result in a large increase of the quantity of sludge from septic tanks to be treated. Nevertheless, large wastewater treatment plants are not systematically able to treat this sludge because they may have reached their nominal load or they are not so numerous in rural zone to avoid too long transportation. The study concerns both, the feasibility of sludge reed beds devoted to the treatment of septage and the assessment of a simultaneous treatment with aerated sludge. The experiments have been carried out on eight pilot-scale drying reed beds (2m²) planted with Phragmites australis. Two filtration layers of either vegetal compost or sand were tested. The study is focused on the commissioning period (first vegetative year) with a loading rate of 30 kgSS.m-2.yr-1. According to these operational conditions, dewatering efficiencies reached approx. 30% DM during summer but less than 20%DM in winter for each filtration layer and sludge. High removal efficiencies, with an average of 96%, 92% and 89% for SS, COD and TKN respectively, were achieved with septage whereas they were lower for the mixture of aerated sludge and septage. The dewaterability of septage and its filtration behaviour were assessed by several parameters (Capillary Suction Time, bound water) which may be some interesting tools for an optimised loading strategy

Flexible Product Line Derivation applied to a Model Based Systems Engineering process

soumis a CSDM 2012Systems engineering enables the successful realization of systems, focusing on defining customer needs early in the development cycle. However there is a lack of methodological support when the development of systems needs to rely on legacy system designs. Furthermore, in the automotive domain, product diversity increases system complexity so much, that reuse becomes much more difficult and time con- suming than usually. We believe a specific strategy must be adopted to prepare for reuse and to achieve systems engineering by reuse. While product line derivation provides the means to obtain single products form a collection of assets, there is still little support for integration with systems engineering practices. In this paper we present an approach which takes into account systems engineering methodolog- ical aspects in product line engineering by rendering the derivation process more flexible. We present the implementation of the tool support for our approach based on the Papyrus1 SysML modeller and exemplify the concepts through a derivation example of the electric parking brake system

Sludge drying reed beds : full and pilot scale study for activated sludge treatment

International audienceSludge drying reed beds have been used for dewatering and mineralization of sludge since the beginning of the 90's, but their insufficient performances in terms of Dry Matter [DM] content and mineralization of the sludge have made necessary new studies. Therefore, 8 pilots of 2m² each and a full-scale plant (13 000 p.e , 8 beds of 470m² in operation for 4 years) have been monitored to examine the influence of the sludge loading rate, the sludge quality and the loading frequency on the dewatering and mineralization efficiencies. Two filtration layers (vegetal compost or sand) and two loading rhythms were tested on pilots which were fed at a loading rate of 25 kgDM.m-2.yr-1 during the first year of operation (commissioning period). Hydraulic behaviour (infiltration rate, outflow), O2 and CO2 relative concentrations in the filtration media, redox potential, pollutants removal and dry matter content were assessed during all the study. The rheological quality of the extracted sludge from full scale beds were assessed and showed that it mechanical behaviour exceed those of sludge of comparable dry matter content, making its spreading easier Therefore, these sludge could easily claim the status of solid and stabilized sludge according to the French regulation. Design and management recommendations (number of beds, loading rates, feeding/rest period) gained from the experiments results are suggested

Challenges and Innovative Technologies On Fuel Handling Systems for Future Sodium-Cooled Fast Reactors

International audienceThe reactor refuelling system provides the means of transporting, storing, and handling reactor core subassemblies. The system consists of the facilities and equipment needed to accomplish the scheduled refuelling operations. The choice of a FHS impacts directly on the general design of the reactor vessel (primary vessel, storage, and final cooling before going to reprocessing), its construction cost, and its availability factor. Fuel handling design must take into account various items and in particular operating strategies such as core design and management and core configuration. Moreover, the FHS will have to cope with safety assessments: a permanent cooling strategy to prevent fuel clad rupture, plus provisions to handle short-cooled fuel and criteria to ensure safety during handling. In addition, the handling and elimination of residual sodium must be investigated; it implies specific cleaning treatment to prevent chemical risks such as corrosion or excess hydrogen production. The objective of this study is to identify the challenges of a SFR fuel handling system. It will then present the range of technical options incorporating innovative technologies under development to answer the GENERATION IV SFR requirements

A Griscelli syndrome type 2 murine model of hemophagocytic lymphohistiocytosis (HLH)

n/