Abstract: An electrochemical cell has an electrolyte container 4 with a wall 5, apertured to let electrolyte soak a membrane 5b. A thin wire loop electrode 13 of (if necessary) precisely known length and cross-section rests on the membrane and contacts a metallised portion 21a of the membrane electrode 21, itself contacting the air through a sinter 22. The loop electrode 13 is sealed into its electrolyte chamber between 21a and 5b by an O-ring 15.If the electrolyte is acetonitrile, then methane in the air can be detected.

Abstract: A surface acoustic wave device comprises a transducer 1 consisting of two electrodes 2 and 3 deposited on the surface of a substrate 4. Transducer 1 is a slanted chirped transducer with short fingers 5 and 6 to focus any acoustic wave generated in the transducer to a position along a line 8 spaced from transducer dependent on the frequency of the signal.

Abstract: A fluid-powered rotary motor, and method of operating the same. Pressured fluid is introduced to the annular clearance between a rotor and a second member, and reaches an outlet by travelling circumferentially within that clearance. The direction of motion of the fluid on entering the clearance is substantially tangential relative to the rotor, so as to avoid any substantial jet impingement of the fluid upon the rotor, and so that the rotor is driven substantially wholly by the hydrodynamic viscous drag action of the fluid upon it. Methods of profiling the rotor surface are disclosed which enhance the surface area over which the viscous drag action can be effected.

Abstract: An elongated probe suitable for lowering down a borehole for nuclear magnetic logging has a pair of similar cylindrical magnets 1 and 2 separated by a gap in which a solenoid 3 is symmetrically disposed. The solenoid has a core 4 of high permeability ferrimagnetic material and has a length preferably equal to half the length of the gap. The magnets 1 and 2 and solenoid 3 with its core 4 are contained within a hollow cylindrical casing 5 of non-magnetic material.

Abstract: In automatically checking circuit boards by raster scanning, it is useful to code and store conductor boundaries for later analysis. Coding time can be reduced by storing an identification of a chain of boundary segments in one of two arrays each time a boundary is detected in a scan line, the identification being stored at an address corresponding to the position of the segment detected. At the same time signals describing the segment are stored in another store at an address related to the identification. When in the next scan line a boundary segment is detected, an address corresponding to its position is used to address the said array and if an identification is found, the new segment is stored in the other store as part of the chain identified. In order to reduce the size of the other store signals describing segments are not stored in areas allocated to chains but in the next vacant location and a RAM stores links between segments.

Abstract: A continuously-variable-ratio automotive transmission, typically of the toroidal-race rolling traction type, in which mechanism comprising a clutch, a brake and two epicyclic combinations--a reversing train and a mixing train--is interposed between the ratio-varying unit and the output of the transmission as a whole. By operation of the clutch and the brake the elements within the mechanism may be arranged in two different combinations whereby the transmission may operate in first and second "regimes", one or other of which will offer efficient transmission throughout the entire operating range of the source of the automotive power.

Abstract: In general a coaxial feeder connected directly into the center of a half-wave dipole antenna disturbs electrical balance and therefore reduces the effectiveness of the screen of the feeder. In the present invention a dipole with two quarter-wavelength elements symmetrically connected through respective identical capacitors to the screen of the feeder is fed through an inductor connected to the junction between one element and its capacitor. By having equal reactances, the capacitors balance the dipole to earth and by means of its phase delay the inductor restores a resistive impedance termination for the feeder.

Abstract: A vehicle monitoring device 10 consists of a damped-pendulum transducer 12 coupled to a potentiometer 14. The analog output of the potentiometer 14, following a braking test with the vehicle concerned, is sampled in a peak/trough detector 16. A microprocessor 18 comprising signal processing unit 20 and arithmetic unit 22 controls the sampling and sums, averages and displays the output of microprocessor 18 on a digital display 24. If desired, a suitably programmed small computer may be used in place of microprocessor 18. According to one aspect of the invention, the device 10 is adapted to serve as a brake-efficiency meter. In this case, the display 24 will be arranged to display the average, or currently-measured, deceleration, as the case may be. In an alternative application, the device 10 is adapted to serve as a safe-slope meter.

Abstract: A process in which material (20) is passed effectively continuously through a gaseous treatment chamber (10) by way of at least one open port (12) is improved by applying gas curtains across the material path to form externally adjacent the port a buffer zone (50) between the chamber interior and the surrounding atmosphere, which zone acts generally to balance the gaseous outflow otherwise occurring through the port. The buffer zone is preferably formed by and between two curtains serially spaced nearer to and further from the port, the curtains being respectively formed with gas drawn from without and within the zone. The zone is suitably sustained in varying conditions by control of curtain flow rate in response to a zone parameter such as temperature.

Abstract: Surgical implants, especially endoprosthetic orthopaedic implants and sutures, are rendered antimicrobial by the presence of a bioerodible metallic silver component, especially a surface coating, which provides in vivo a sustained release of silver ions in a concentration sufficient to provide a localized antimicrobial effect but insufficient to cause significant damage to connective tissue. Latently bioerodible silver components of an implant can be activated by, for example, abrasion, heating to above about 180.degree. C. or, especially, contact with hydrogen peroxide.

Abstract: A method for identifying specific bacterial species in derived samples is based on 26 tests for the presence of constitutive enzymes, which, with the exception of two tests which require about two and a half hours, can be done relatively quickly, and without need for bacterial growth. By quantifying the amount of enzyme identified by the substrate test, a highly reliable identification of bacterial species present can be made. A kit, comprising substrates specific to the enzymes to be tested for, is provided for carrying out the test.

Abstract: When sound waves are intentionally attenuated by systems using destructive interference temporal changes sometimes cause less than optimum performance. In the present invention the transfer function of a signal processing system connected between a sound detector and a sound generator destructively interfering with an unwanted sound is modified at intervals as a result of sequential measurements of the transfer function between the sound detector and a further sound detector downstream from the generator. For this purpose a data processor calculates the required transfer function and causes a data processor to vary the coefficients of a digital filter comprising the signal processing system.

Abstract: Pesticidal compounds have the formula: ##STR1## wherein D represents hydrogen or a cyano or ethynyl group;B represents hydrogen or an alkyl or alkenyl group;A represents an alkyl group or a halogeno group or a CF.sub.3 group;n is 0 or an integer of 1-4; andRCOO is the residue of an acid RCOOH which is a 2,2-dimethyl-cyclopropane carboxylic acid carrying at the 3-position a dihalovinyl, an alkenyl or a carboalkoxyalkenyl group, provided that (1) when the group --CH.sub.2 CH.dbd.CHB is located at the 4-position on the ring with respect to the ester linkage, then D must be hydrogen and the group carried at the 3-position on the cyclopropane ring of the acid must be a dihalovinyl group and (2) when the group --CH.sub.2 CH.dbd.CHB is located at the 3-position on the ring and D is a CN group, then n must be 0.

Abstract: The present invention concerns a device for analyzing chemical substances and monitoring chemical reactions in which cuvettes on a turntable are rapidly scanned by light at test and reference wavelengths and intensity of the light after passage through the cuvettes monitored by a photodetector. The output of the photodetector is logically processed so that measurements can be made of the varying optical densities in the samples scanned.

Abstract: A process in which a culture of a methane-oxidizing bacterium or an extract thereof containing a methane oxidizing system is used as oxidizing agent for the oxidation of a higher short-chain alkane, an alkene or a cyclic organic compound.

Abstract: Compounds of the general formula: ##STR1## wherein n is an integer from 2 to 6, m is an integer from 2 to 4, p is an integer from 1 to 3, R is H, an amino protecting group conventionally used in peptide chemistry or a solid phase support, R.sub.1 is H or a carboxy protecting group conventionally used in peptide chemistry and R.sub.2 is H or alkyl or H.sub.2 N--C.dbd.NH are useful for inhibiting the activity of enterokinases.

Abstract: Apparatus to control the automatic placing of material along a junction between surfaces with reference to the form and position of the junction including means controllably movable to deposit material progressively along the junction in response to a control signal, means linked to the movement of the means to deposit material to produce an image of the surfaces and junction, filter means to remove from the image information resulting from illumination at other than a specific wavelength with a tapped delay line to provide a specific impulse response, means to extract from the image that portion unambiguously defining the junction form and position, means responsive to said image portion to derive said control signal to control the means to deposit material to move in a required manner along said junction to deposit material.

Abstract: In single fibre electromyography it is useful to be able to measure intervals between waveforms (obtained from needle electrodes inserted into muscle fibres) reaching certain levels. A circuit is described, which is of general application, and which allows such intervals to be measured. First and second comparators which have adjustable reference levels receive an incoming waveform and, by means of polarity select circuits, provide outputs only when the reference levels are passed by waveform portions changing in selected respective directions. The time at which the first comparator is satisfied is available from a counter 33 but it is only passed to a computer interface when the second comparator has also been satisfied. Enable circuits prevent an output to the computer unless the comparators are satisfied within selectable time intervals.

Abstract: This invention relates to a method of impregnating wood in order to protect it against fungal decay. Conventionally wood has been treated with copper-chromium-arsenic preservatives in a one stage treatment, e.g. by impregnating the wood with a solution of these compounds. The chromium component serves to fix the copper in the wood to prevent it from leaching out. It has now been found that a two-stage treatment in which (1) the copper and fixative agent are impregnated without arsenic and (2) the arsenic is impregnated separately, improves resistance of the wood to soft-rot fungi. The invention is particularly useful for treating hardwoods.

Abstract: Histidine derivatives of formula I are useful inter alia in peptide synthesis. ##STR1## wherein: X represents --CH.sub.2 OCH.sub.2 Ar, in which Ar is a phenyl substituent optionally substituted by one or more halogen, alkoxy, alkyl or nitro groups;Y, which differs from X, represents hydrogen, a protective group capable of inhibiting self coupling during formation of a peptide bond, an amino acid residue, a peptide chain or an antibiotic residue;E represents OH,OM,M representing an alkali metal or ammonium, OR, R representing an alkyl, aryl, aralkyl or alkaryl group, an amino acid residue, a peptide chain or an antibiotic residue;the compound I being optionally in the form of a hydrate or acid salt.In compounds I of especial interest, X represents benzyloxymethyl or p-bromobenzyloxymethyl, Y represents t-butyloxycarbonyl and E represents --OH.