Abstract: A polyisocyanate composition used for binding lignocellulosic materials comprising a polyisocyanate prepolymer, the prepolymer being the reaction product from a polyisocyanate comprising an isomer mixture of diphenylmethane diisocyanate and at least one polyether polyol having from 2 to 8 hydroxyl groups, wherein the polyether polyol comprises polymerized alkylene units containing at least 15% ethylene oxide units.

Abstract: Organic circuit elements and methods are disclosed. An organic circuit element includes a plurality of members, each of which includes an oligonucleotide duplex. The plurality of members includes at least one donor member for receiving conduction electrons from an electron donor, at least one acceptor member for communicating with an electron acceptor to provide a region of attraction for the conduction electrons, and at least one regulator member intersecting with at least one of the plurality of members to define at least one electric field regulation junction, for cooperating with an electric field regulator to regulate an electric field at the junction. A method of regulating an electronic signal between first and second locations in a conductive nucleic acid material includes varying an electrostatic potential at a third location in the nucleic acid material interposed between the first and second locations. The third location may include the regulation junction.

Abstract: An improved process for the manufacture of CF3CHF2 by contacting 1,2-dichloro-1,1,2-trifluoroethane (CClF2CHClF) or 1-chloro-1,1,2,2-tetrafluoroethane (CHF2CClF2) or mixtures of CF3CHCl2 and CClF2CHClF or mixtures of CF3CHClF and CHF2CClF2 with HF in the presence of a Cr2O3 catalyst prepared by pyrolysis of ammonium dichromate, the reaction being conducted under controlled conditions whereby the production of CF3CHF2 is maximized, and the formation of chloropentafluoroethane (CF3CClF2) and other perhalo derivatives is minimized. The subject hydrogen-containing compound is useful as a blowing agent, propellant, refrigerant, fire extinguishing agent, or sterilant carrier gas.

Abstract: A process for the production of a hydrofluoroalkane, particularly 1,1,1,2-tetrafluoroethane or pentafluoroethane, which comprises contacting a hydrochlorofluoroethane or a hydrochlorofluoroethene with hydrogen fluoride and a fluorination catalyst and recovering a hydrofluoroalkane from the resulting products, the hydrochlorofluoroethane having the formula CClXYCFHZ and the hydrochlorofluoroethene having the formula CClA-CFZ wherein X and Y are each independently chlorine or fluorine, Z is chlorine or hydrogen and A is chlorine or fluorine provided that where each of X and Y is fluorine then Z is hydrogen. A preferred embodiment of the process is the production of 1,1,1,2-tetrafluoroethane from the hydrochlorofluoroethene CCl2═CFH.

Abstract: An organometallic composition comprises a complex of at least one metal selected from the group consisting of titanium, zirconium and hafnium and an acetoacetate ester in which the molar ratio of Ti or Hf to acetoacetate ester is in the range 1:2.5 to 1:10 or the molar ratio of Zr to acetoacetate ester is in the range 1:4.5 to 1:10 and said acetoacetate ester is an ester of an alcohol containing 1 to 6 carbon atoms. The organometallic composition is useful in polyisocyanate compositions, particularly those used as binders for lignocellulosic materials, and polyisocyanate compositions containing the organometallic compositions of the invention have good stability on storage.

Abstract: A pressure transducer, particularly a transducer for measuring gaseous pressure differential across a chamber wall is disclosed. The transducer finds particular application in an air cleaning system. The pressure transducer of the invention is designed and arranged to include a load cell disposed between the chamber wall and a diaphragm which is designed and arranged to seal about a hole in the chamber wall.

Abstract: According to the present invention there is provided a process for the selective introduction of one or more fluorine atoms into a disubstituted aromatic compound in an acid medium with fluorine gas characterized in that the acid medium has a dielectric constant of at least 20 and a pH of less than 3. The present process provides a cost effective means of selectively introducing one or more fluorine atoms into an aromatic compound in good overall yield.

Abstract: A method of halogenating an aromatic compound which comprises the steps of reacting an halogenating agent with the aromatic compound in the presence of fluorine and an acid, wherein the halogenating agent is at least one of an iodinating agent, a brominating agent and an chlorinating agent.

Abstract: Apparatus for sensing the passage of sheets (1) through a nip formed by rollers (5 and 6), includes a core (14), moving with the shaft of one of the rollers, and a flat coil (15) connected to an oscillator circuit for sensing the deflection of one roller relative to the other. The oscillator circuit (18) provides a train of signals the frequency of which varies with the amount of the relative deflection of the rollers, and a counter (19) counts the signals from the oscillator in a fixed time interval. A store (22) stores counts representing the relative deflections of the rollers in a cycle of movement of the rollers when no sheet is present. The difference between a subsequent count and a stored count for a corresponding position in the cycle of rotation of the rollers is compared with a predetermined threshold, to establish the presence or absence of a sheet between the rollers.

Abstract: Apparatus for sensing the passage of sheets (1) through a nip formed by rollers (5 and 6), includes means for sensing the deflection of one roller relative to the other, the sensing means including an oscillator (18) providing a train of signals the frequency of which varies with the amount of the relative deflection of the rollers, and a counter (19) counting the signals from the oscillator in a fixed time interval. Means (23) are provided for storing counts representing the relative deflections of the rollers in a cycle of movement of the rollers when no sheet is present, and for comparing the difference between a subsequent count and a stored count for a corresponding position in the cycle of rotation of the rollers, with a predetermined threshold, to establish the presence or absence of a sheet between the guide members. The sensing means may comprise a core (14), moving with the shaft of one of the rollers, and a solenoid (15) connected to the oscillator circuit.

Abstract: A fuel pumping apparatus includes an injection pump to which fuel is supplied by means of a feed pump. A valve is provided to control the output pressure of the feed pump and a pressure responsive piston responsive to the output pressure of the feed pump modifies the timing of delivery of fuel by the injection pump. The valve comprises first and second valve elements which are resiliently loaded in one direction. The first valve element is exposed to the output pressure of the feed pump and is movable by this pressure to allow fuel to flow through an orifice. The second valve element is subjected to the pressure upstream of the orifice and is movable firstly to reduce the force acting on the first valve element due to the resilient loading and after moving a predetermined distance progressively opens a spill port.

Abstract: A fuel injection pumping apparatus includes an injection pump driven in timed relationship with an associated engine and a resiliently loaded fluid pressure operable member for controlling the timing of delivery of fuel by the injection pump. Means is provided for generating a pressure responsive to the speed of and/or load on the associated engine an this pressure is applied to the aforesaid member so that the timing of delivery of fuel is variable. The apparatus also includes a piston movable to adjust the force exerted by the resilient means on the member and valve means is provided for controlling the application of fluid pressure to said piston, the valve means being responsive to the speed of operation of the associated engine.

Abstract: A fuel injection apparatus includes an axially movable member movable to determine the amount of fuel supplied by the apparatus. The member is acted upon by a weight mechanism including pivotal weights the force exerted by which is opposed by a governor spring adjustable from the exterior of the apparatus. Increase of the force exerted by the spring can result in sudden movement of the member so that temporarily too much fuel is supplied to the engine. This difficulty is minimized by providing a dash-pot which restricts the rate of movement of the member under the action of the governor spring at low engine speeds. The dash-pot is combined with a resilient means the force exerted by which is less than that of the governor spring at moderate engine speeds so that the dash-pot action is only obtained at low engine speeds.

Abstract: A liquid fuel injection pumping apparatus includes an injection pump to which fuel is supplied by a feed pump by way of a throttle which includes an axially movable member. The pressure of fuel upstream of the throttle is controlled by a valve so that its pressure varies in accordance with the law RN.sup.2. The apparatus also includes a further valve which provides a substantially constant pressure and this pressure is applied to a piston by way of a further orifice the size of which depends upon the setting of the throttle. The further piston influences the timing of injection of fuel by the apparatus and in addition a pressure which is proportional to the square of the speed at which the apparatus is driven, is generated and is also used to influence the timing of delivery of fuel.

Abstract: A fuel injection pumping apparatus includes an injection pump for supplying fuel to an engine, feed pump for supplying fuel to the injection pump, and throttle means for controlling the amount of fuel supplied by the feed pump to the injection pump. Intermediate the throttle means and the feed pump is a first orifice, and downstream of this orifice is a tapping to which a control pressure is applied to a device operable to adjust the timing of injection of the injection pump. A valve is provided which includes a variable orifice connected in parallel with said first orifice, the valve being responsive to the outlet pressure of the feed pump to control the effective value of the first orifice.

Abstract: A fuel injection pumping apparatus comprises an injection pump which is driven in timed relationship with the associated engine, and a feed pump which supplies fuel under pressure to the injection pump. A throttle member controls the quantity of fuel which is supplied to the injection pump and a fluid pressure operable piston which is movable against the action of a spring to advance the timing of injection of fuel to the engine, the piston being subjected to the outlet pressure of the feed pump. A fluid pressure operable stop member is provided which when the apparatus is at rest, positions the piston to provide the correct timing of injection of fuel for starting purposes.

Abstract: A fuel injection pumping apparatus for supplying fuel to an internal combustion engine in which there is provided a feed pump which supplies fuel from its outlet to an injection pump by way of a throttle valve. The outlet pressure of the feed pump is controlled by a relief valve which includes a valve element movable by the outlet pressure of the feed pump to spill fuel between the inlet and outlet of the feed pump. The valve element is subjected to a pressure which is generated by a device and which varies in accordance with the square of the speed at which the apparatus is driven. A pair of restrictors are disposed in a flow path between the outlet of the feed pump and the device and a branch conduit applies the pressure intermediate the restrictors to a fluid pressure operable device which controls the operation of the injection pump.

Abstract: A fuel injection pumping apparatus includes an injection pump to which fuel is supplied by means of an axially movable shuttle which is contained within a cylinder. Fuel is supplied to one end of the cylinder through a metering valve from a first source of fuel under pressure. The fuel contained in said one end of the cylinder is displaced to the injection pump by applying fuel under pressure to the other end of the cylinder containing the shuttle from a further source of fuel under pressure. The pressure of the further source of fuel is higher than that of the first mentioned source.