Abstract: The invention relates to a method for producing a C4-type plant having a modified carbon metabolism, comprising the following steps: an expression cassette, which comprises a nucleotide sequence that codes for a phosphoenolpyruvate carboxylase (PEPC), is introduced into at least one cell of plant C4; the cell thus transformed is cultivated in such a way as to regenerate a C4 plant containing said expression cassette in the genome thereof.

Abstract: The invention relates to a method for producing a C4-type plant having a modified carbon metabolism, comprising the following steps: an expression cassette, which comprises a nucleotide sequence that codes for a phosphoenolpyruvate carboxylase (PEPC), is introduced into at least one cell of plant C4; the cell thus transformed is cultivated in such a way as to regenerate a C4 plant containing said expression cassette in the genome thereof.

Abstract: A circulating fluidized bed reactor includes a lower zone having a fluidization grid, primary and secondary air injection inlets, and fuel feed inlets, an upper zone, internal bubbling beds at the top of the lower zone collecting solid matter from recirculation internal to the reactor and delivering a fraction thereof to external bubbling bed heat exchangers close coupled with the walls of the reactor level with the internal beds. The external heat exchangers reject the solid matter into the lower zone after exchanging heat with an external fluid. The reactor is simple in structure and benefits from the advantages of bubbling external beds while maintaining conventional design in the lower zone.

Abstract: The reactor includes: a lower zone (I) having a fast circulation fluidized bed; a zone having a dense fluidized bed (13) and located adjacent to the top of the lower zone, being separated therefrom by a dividing wall, the top layer of the dense bed receiving falling particulate materials, and its bottom layer returning these materials to the lower zone (I); and a higher zone having a fast circulation fluidized bed. The invention is applicable to boilers.

Abstract: The reactor includes: a lower zone (I) having a fast circulation fluidized bed; a zone having a dense fluidized bed (13) and located adjacent to the top of the lower zone, being separated therefrom by a dividing wall, the top layer of the dense bed receiving falling particulate materials, and its bottom layer returning these materials to the lower zone (I); and a higher zone having a fast circulation fluidized bed. The invention is applicable to boilers.

Abstract: An ignition and combustion supporting burner for pulverized solid fossil fuel comprises an axial conduit for feeding the pulverized fuel in a primary combustion supporting gas. The shape of a refractory tap-hole enables the initial part of the flame to be confined. A conduit for feeding tertiary combustion supporting gas is concentric with the tap-hole and partially or totally surrounds it. The burner also incorporates a flame detector device and an igniter in the refractory tap-hole or in the axial conduit. The axial conduit is provided with translation means providing for adjustment of the length of a chamber for preliminary mixing of the fuel and part of the combustion supporting gas comprised between the end of this conduit and the inlet of the tap-hole.

Abstract: A stretcher frame for an artist's canvas is formed of four wooden side pieces with simple mitred ends, joined at the corners by four corner connector assemblies. Each corner connector assembly has a pair of perpendicularly interconnected arms of U-shaped cross section which slidably receive two of the wooden side pieces. A support bracket projects inwardly from each arm, and a connecting bracket projects inwardly from each side piece. A threaded rod is affixed to the connecting bracket and extends through the support bracket, and a spring on the rod biases the support bracket outwardly to apply tension to a canvas on the frame. To deter inward flexing of the side pieces, cross members extend between opposed pairs of side pieces. Each cross member includes a threaded rod, a spring on the threaded rod, a tube which is biased by the spring and receives the threaded rod, and a nut which is threaded on the rod to compress the spring.