Etudes des transformations des formes du carbone, azote, phosphore, soufre, et des principaux elements mineraux au cours de la mesure de la demande totale en oxygene—I. Transformation des formes du carbone et des principaux cations

Les expériences réalisées sur le D.T.O. mètre de laboratoire IONICS 225 de la Dow Chemical, ont permis de caractériser, aprés l'action catalytique à haute température, les formes stables du carbone, de l'hydrogéne et des cations sodium, potassium, calcium, magnésium.Dans l'intervalle 0–250 mg O₂ l ou la réponse du capteur d'oxygène est proportionnelle à la concentration en matière organique nous avons démontré expérimentalement que le carbone organique ou minéral est transformé en CO₂ l'hydrogène en H₂O, et les cations sodium, potassium, calcium, magnésium en leurs oxyde et hydroxyde correspondants.Les ions bicarbonates et carbonates sont réduits et créent une interference négative: par contre les cations sont oxydés et creent une interférence positive dans la mesure de l'équivalent oxygéne par le D.T.O. métre.     

Thermal expansion stress in a metallic matrix composite:in situ TEM observations

A metallic matrix composite material (2024-type aluminium alloy reinforced with 25 vol % SiC whiskers) wasin situ thermally cycled in a transmission electron microscope. Dislocation movements were observed between 180 and 400 °C. The local shear stress due to the difference between the thermal expansion coefficient of matrix and fibres is estimated from the radius of curvature of mobile dislocations. The experimental values of the internal stress are discussed.     

Low earth orbit satellite systems for communications

It may be that we are now entering the era of LEO constellation satellite communications after thirty years of domination by the GEO systems. This paper heralds the coming of the new era with a tutorial approach to the system design and trade-offs of LEO constellation system design. It discusses orbital configurations, network topologies and routeing considerations, multiple access schemes and link performance design. In so doing it brings out the major design parameters and how they interact with each other. Also considered are the service applications for the LEO constellation systems, and the important difference between real-time and delayed communication systems is highlighted. Examples of single and multi-beam (cellular) coverage system link designs are presented for L-K_a frequency bands. Future papers will consider aspects of the LEO spacecraft and launchers.     

Multi-level analysis of low-cost Z-pinned composite joints: Part 2: Joint behaviour

In the framework of the E-U program ALCAS (Advanced Low-Cost Aircraft Structure), a new Z-pinning technique was developed by EADS Innovation Works. This technology was used to manufacture low-cost Z-pinned junction demonstrators (L and T shaped specimens) typical of aeronautical structures. In order to understand load transfer mechanisms in this kind of assembly, a multi-level analysis was performed. In the first part of this study, tension and shear pin behaviour was investigated as well as pin pull-out from neat resin or laminate. An analytical model was proposed to predict the maximum load capability of a single pin for an insertion depth of less than 8 mm which correspond to the usual technology. Now, in this second part, we demonstrate that the behaviour of the junction under pull-out, shear and unfolding is globally homothetic to the mechanical behaviour of a pin. This study provides the basis for a pre-sizing methodology for Z-pinned junctions under complex loading.     

Lighting transfer across multiple views through local color transforms

Computational Visual Media - We present a method for transferring lighting between photographs of a static scene. Our method takes as input a photo collection depicting a scene with varying...     

Impact of sun patch and three-dimensional heat transfer descriptions on the accuracy of a building’s thermal behavior prediction

A thermal transient numerical model (M_3D) which considers the three-dimensional heat transfer through the envelope of a room and the sun patch through a window has been developed and validated in a recent paper. The use of a refined spatial and temporal discretization allows considering more precise interactions between the sun patch projection with the structure and quick time perturbations in the stresses. This is particularly necessary for highly insulated and low energy consumption buildings. In this new paper, M_3D is subsequently transformed to simpler configurations, close to classical modelling thermal building simulation software that neglects the sun patch and the 3D heat transfer, in order to quantify the main contributions of this model. A first configuration is to consider one-dimensional heat conduction for the envelope and the transmitted solar radiation is only projected onto the floor (M_1D). A second configuration considers also one-dimensional heat conduction but the transmitted beam radiation falls on each wall or floor that is impacted (M_1D,sp). Comparison between experimental data and numerical results of these three models shows, as expected, that M_1D and M_1D,sp are less accurate than M_3D. This is particularly true when wanting to evaluate surface temperature distributions or heating power evolution in winter.     

Development on systems configuration in ITER Tokamak Complex and Auxiliary Buildings

The ITER site consists of almost 30 buildings to service the Tokamak machine which is located in the centre of the Tokamak Complex facility with the Tokamak-, Diagnostic- and Tritium building.The design of a large part of the ITER plant systems will be executed by the ITER Domestic Agencies or their industrial suppliers under functional specifications provided by the ITER Organization. At the same time, the detailed design of the building is carried out by the European Domestic Agency ‘Fusion for Energy’ (F4E).In order to allow an efficient identification of the ITER configuration as well as to manage the concurrent engineering activities and to simplify the identification and assessment of changes, the design of each ITER plant systems is described in the so-called Configuration Management Models (CMM). These are light CATIA^® 3D models that define the required space envelope and the physical interfaces in-between the systems and the buildings.The paper describes the procedure adopted for the control of the baseline configuration of the Tokamak Complex facility and Auxiliary Buildings with their associated plant systems and illustrates the current status as well as recent developments in the different systems.