Abstract: A method of data transfer from a tenant to a service provider comprises encrypting the data with a public key of a key pair generated by a secure device within the service provider system. The data thus cannot be accessed by the service provider during transmission. The data is generated with a corresponding access control list, which specifies that a valid certificate must be presented in order to grant a particular use of the data once stored. The tenant can thus retain control of the use of the data even though it has been transferred out of the tenant system. A method of controlling use of data securely stored in the service provider system comprises issuing a use certificate having an expiry time to the party requesting use of the data. The use certificate must be validated before use of the stored data is granted. This enables the tenant to grant use of the stored data for a limited time period.

Abstract: A method of reducing the aggregation and deposition of asphaltene from a fluid containing asphaltene, such as crude oil, which method comprises the addition to the fluid of a compound of formula (1): wherein A is an optionally substituted ring system containing 6 to 14 carbon atoms; n is at least 1 and may equal the number of positions available for substitution in A; each X is independently a linker group; and each R is independently a hydrocarbyl group containing 10 to 25 carbon atoms.

Abstract: A power amplifier has a pair of FETs of opposite kinds connected together to form a source/drain circuit connected with an output. A second pair of high speed transistors is connected to the input and forms a collector/emitter circuit connected to the gates of the FETs. Capacitors are connected across the second pair of transistors and the pair of FETs respectively. Opposing current sources connect with the bases of the second pair of transistors via a resistor divider.

Abstract: A power amplifier has a pair of FETs of opposite kinds connected together to form a source/drain circuit connected with an output. A second pair of high speed transistors is connected to the input and forms a collector/emitter circuit connected to the gates of the FETs. Capacitors are connected across the second pair of transistors and the pair of FETs respectively. Opposing current sources connect with the bases of the second pair of transistors via a resistor divider.

Abstract: A method of controlling asphaltene precipitation in a fluid comprising the addition of a precipitation inhibitor to the fluid containing the asphaltene.