Abstract:
Novel hemiacetalised derivatives of polyketones (linear alternating polymers of carbon monoxide and one or more alkenes are prepared by reacting the polyketone with a diol of formula HOZOH, where Z = -(C(R)2)n-, the R groups are independently H, OH or C1 to C10 alkyl or hydroxyalkyl and n is 2 to 6. The process of preparation is characterised by using a molar ratio of diol to carbonyl groups in the polyketone of at least 5:1.
Abstract:
This invention relates to a composition for cleaning contaminated electronic substrates. The compossition comprises a blend of 2-30% w/w of ethoxyethoxy ethanol and at least one other glycol ether derivative selected from butoxyethoxy ethanol, methoxypropoxy propanol, ethoxypropoxy propanol and C1-C5 monocarboxylic acid esters thereof. These esters are more environmentally safe and more user friendly than halohydrocarbons used hitherto for cleaning fluxes and solders from circuit boards.
Abstract:
A method for determining the height and length of a fracture (2) in a borehole (1) involves generating pressure waves at closely spaced frequencies by means of a transmitter (3) at the wellhead. The response at the wellhead of the wellbore-fracture system to the resultant standing waves is measured by means of a transducer (6). A theoretical model of the wellbore-fracture system is generated and compared with the measured response to determine the height and length of the fracture.