Abstract: A downhole apparatus has a casing string and a degradable plug positioned in the casing string to block flow therethrough. An upper membrane covers an upper end of the degradable plug. The upper membrane is made up of a plurality of separable membranes. A lower membrane covers a lower end of the degradable plug and is comprised of a plurality of separable membranes.

Abstract: A downhole apparatus comprises a casing string with a removable plug therein to block flow therethrough. A flow barrier is positioned in the casing below the removable plug and the removable plug and the flow barrier defining a buoyancy chamber therebetween. A debris barrier positioned above the removable plug comprises a rigid annular ring with a flexible diaphragm covering the center opening defined by the annular ring.

Abstract: A downhole apparatus comprises a casing string with a fluid barrier connected in the casing string. A degradable plug is positioned in the casing string above the fluid barrier. The degradable plug and fluid barrier define upper and lower ends of a buoyancy chamber in the casing string. The degradable plug may be degraded to leave an open bore through the casing string after the casing string is lowered into a wellbore.

Abstract: A downhole tool. The downhole tool may include a tubular body and an inner sleeve that is slidable within the tubular body. The tubular body may include a port that allows fluid flow between a bore of the downhole tool and an area outside of the tubular body. The downhole tool may be sequentially positionable in a run-in position that blocks fluid flow through the port in the tubular body, then in an open position that allows fluid flow through the port in the tubular bod, and then in a closed position that blocks fluid flow through the port in the tubular body.

Abstract: The present disclosure relates to a process for the synthesis of highly crystalline carbon nanotubes (CNTs). Processes known in the art employ post-synthesis processes such as oxidation or hydrothermal treatment to produce CNTs with high crystallinity. The present disclosure produces highly crystalline CNTs at a low growth temperature and without hydrogen flow condition and without employing any post-production process. The process disclosed in the present disclosure produces CNTs having a crystallinity greater than 5 which makes them suitable for various industrial applications.

Abstract: The present disclosure relates to a process for the synthesis of highly crystalline carbon nanotubes (CNTs). Processes known in the art employ post-synthesis processes such as oxidation or hydrothermal treatment to produce CNTs with high crystallinity. The present disclosure produces highly crystalline CNTs at a low growth temperature and without hydrogen flow condition and without employing any post-production process. The process disclosed in the present disclosure produces CNTs having a crystallinity greater than 5 which makes them suitable for various industrial applications.

Abstract: A photonic communication system communicates M signals over a waveguide by modulating M wavelengths of light. N photonic rings at a receiver, where N is greater than M, are used to demodulate the M wavelengths. The modulated frequencies and resonant wavelengths of the receive rings are allowed to drift relative to one another. The number of receive rings is greater than the number of modulated frequency, and the number and optical characteristics of the receive rings are selected such that a subset of the receive rings effectively demodulates over the operational frequency range of the incoming light. The system tracks relative drift between the modulated wavelengths and the resonant wavelengths of the receiving rings and automatically selects the correct modulated signal or signals from among the receiving rings. The free spectral ranges and optical lengths of the receive rings are selected to reduce or minimize the number of receive rings required to span the optical bandwidth of the modulated light.

Abstract: A process for the preparation of optically pure R (?) salbutamol of formula (6) and its pharmaceutically acceptable salts by using a (+) 4-nitro tartranilic acid as the resolving agent and a binary solvent system comprising alkyl acetate and C1 to C4 branched or normal chain alcohol for dissolution of the racemic mixture and resolving agent and purification of the 4-nitro tartranilic acid salt of R (?) salbutamol. 4-nitro tartranilic acid salt of R (?) salbutamol is converted into formic acid salt of R(?) 4-benzyl salbutamol followed by basification and debenzylation to form optically pure R(?) salbutamol. Optically pure (R)-salbutamol is obtained in good yield and high purity. The optically pure R(?)salbutamol is optionally converted into pharmaceutically acceptable salts.