Abstract: A method, system and computer program product is disclosed for using a constrained pressure residual (CPR) preconditioner to solve adjoint models. A linear system of fluid flow equations comprising a plurality of variables that represent fluid flow properties in a geological formation of a subterranean reservoir is provided. Matrix (Ã)T, which comprises a transpose of a Jacobian matrix associated with the linear system of fluid flow equations, is constructed. A constrained pressure residual preconditioner MCPRA?1 is constructed responsive to the matrix (Ã)T. Matrix equation (Ã)Ty=d is then solved using the constrained pressure residual preconditioner MCPRA?1.

Abstract: A method, system and computer program product is disclosed for using a constrained pressure residual (CPR) preconditioner to solve adjoint models. A linear system of fluid flow equations comprising a plurality of variables that represent fluid flow properties in a geological formation of a subterranean reservoir is provided. Matrix (Ã)T, which comprises a transpose of a Jacobian matrix associated with the linear system of fluid flow equations, is constructed. A constrained pressure residual preconditioner MCPRA?1 is constructed responsive to the matrix (Ã)T. Matrix equation (Ã)Ty=d is then solved using the constrained pressure residual preconditioner MCPRA?1.

Abstract: A method, system, a program storage device and apparatus are disclosed for conducting a reservoir simulation, using a reservoir model of a region of interest, wherein the region of interest has been gridded into cells. Each cell has one or more unknown variable. Each cell has a node. A graph of the nodes is represented by a sparse matrix. The graph is an initially decomposed into a pre-specified number of domains, such that each cell exists in at least one domain. The cells and domains are numbered. Each cell has a key, the key of each cell is the set of domain numbers to which the cell belongs. Each cell has a class, the class of each cell being the number of elements in the cell. The cells are grouped into connectors, each connector being the set of cells that share the same key. Each connector having a connector class, the connector class being the number of elements in the key of the connector.

Abstract: A method, system and apparatus are disclosed for conducting a reservoir simulation, using a reservoir model of a gridded region of interest. The grid of the region of interest includes one or more types of cells, the type of cell being distinguished by the number of unknown variables representing properties of the cells. The cells share a common variable as an unknown variable. The method includes the steps of identifying different cell types for the grid; constructing an overall matrix for the reservoir model based on the different cell types; at least partially decoupling the common variable from the other unknown variables in the matrix by using a reduction process to yield a reduced matrix; mathematically breaking up the variables in the reduced matrix into k subsets by cell types; applying an overlapping multiplicative Schwartz procedure to the reduced matrix to obtain a preconditioner and using the preconditioner to solve for the unknown variables.

Abstract: A grinding machine for grinding short components has a grinding enclosure 18 in which the grinding operation takes place. The grinding enclosure contains the grinding wheel, a workpiece holder and a wheel dressing station, but all other components of the machine are mounted outside the enclosure, so as to be kept out of contact with coolant and swarf. The enclosure is sealed, to an extent sufficient to prevent egress of coolant and grinding debris and has openable doors to allow loading and unloading of workpieces and mounting and removal of grinding wheels.

Abstract: A method, system, a program storage device and apparatus are disclosed for conducting a reservoir simulation, using a reservoir model of a region of interest, wherein the region of interest has been gridded into cells. Each cell has one or more unknown variable. Each cell has a node. A graph of the nodes is represented by a sparse matrix. The graph is an initially decomposed into a pre-specified number of domains, such that each cell exists in at least one domain. The cells and domains are numbered. Each cell has a key, the key of each cell is the set of domain numbers to which the cell belongs. Each cell has a class, the class of each cell being the number of elements in the cell. The cells are grouped into connectors, each connector being the set of cells that share the same key. Each connector having a connector class, the connector class being the number of elements in the key of the connector.

Abstract: A method, system and apparatus are disclosed for conducting a reservoir simulation, using a reservoir model of a gridded region of interest. The grid of the region of interest includes one or more types of cells, the type of cell being distinguished by the number of unknown variables representing properties of the cells. The cells share a common variable as an unknown variable. The method includes the steps of identifying different cell types for the grid; constructing an overall matrix for the reservoir model based on the different cell types; at least partially decoupling the common variable from the other unknown variables in the matrix by using a reduction process to yield a reduced matrix; mathematically breaking up the variables in the reduced matrix into k subsets by cell types; applying an overlapping multiplicative Schwartz procedure to the reduced matrix to obtain a preconditioner and using the preconditioner to solve for the unknown variables.

Abstract: A grille (3) for use adjacent an outlet of a heating, ventilating or air conditioning system comprising a frame (15) and a plurality of blades (25) extending between opposed frame parts. Each blade (25) has a spindle (26) which is rotatably supported within opposed slots (21) formed in the opposed parts of the frame. The slots (21) are open at one end to permit the insertion of the blade spindle and the spindle is supported at the closed ends of the slots. The grille (3) further comprises means for retaining the blade spindles (26) in the slots (21). The retaining means comprise an element (30) mountable upon the frame (15) of the grille such that part of the retaining element (30) engages the blade spindles (26) when mounted upon the frame and prevents the spindles (26) from moving out of the open ends of the slots (21).