An instrument for assessing roughness of a surface having a probe arranged to engage the surface and be urged towards the surface in the direction of the probe which is arranged to yield when the probe is at a critical angle to the surface dependent on the surface roughness.

Apparatus for measuring the endface angle of a cleaved optical fibre (1) includes a light source (3) for injecting optical energy into that end (1a) of the optical fibre (1) opposite to that whose endface angle is to be measured. Means are provided for tapping optical energy passing along the optical fiber (1) in both directions. Photodetectors (5,6) measure the signal strength of the optical energy tapped from the optical fibre (1) in both directions. The ratio of these measured signal strength...

Features of the endface of a dielectric member are assessed by means of a reflected diffraction pattern. A plurality of light beams 6, 7 which intersect in a region containing the endface 8 can be used to generate a diffraction pattern 10 which subtends an angle of at least 180.degree. at the endface 8. Such a diffraction pattern 10 contains information about the endface 8 and may be used, in particular, to locate the plane in which the endface 8 lies. Embodiments of the invention find particula...

A method and apparatus for the indentification of corrosion in a metal object is disclosed. The method comprises analyzing the statistical distribution of signals generated between two electrodes, typically exposed to the same corrosion conditions as the metal object, and preferably analyzes the skewness and kurtosis of the signals. Neural nets are preferably used in the analysis.

An apparatus for producing sounds of selectable pitch, quality and sound pressure level and a method for using the apparatus in assessing a person's hearing are disclosed. The apparatus includes a function generator for generating the fundamental frequency of the sound to be produced, a formant filter circuit for passing only one or more resonant frequencies of the fundamental frequency so as to vary the quality of the sound to be produced, and a level control for varying the loudness of the sou...

Instruments are disclosed for testing the susceptibility of PCM regenerators to rear end and far end crosstalk noise. The instruments of the invention are more compatible with PCM system engineering rules since certain important PCM system parameters are synthesized in the circuitry. The instrument for measuring susceptibility to rear end crosstalk includes a filter having a voltage transfer function 1/R.sub.3 .vertline.f/.sub.fo .vertline..sup.3/4 and the instrument for measuring susceptibility...

A hazard assessment probe circuit for use at proposed blasting sites for determining the electrical current which would flow in any given electric blasting cap circuit due to the presence of extraneous electrical energy. With such a determination one can, with a high degree of certainty, conclude whether or not electric blasting operations at a proposed site can be conducted without risk of accidental detonation of the blasting cap, and any primary explosives adjoining the cap, as a result of pi...

For assessing ground quality, such as a condition of a racetrack, a handheld device has a shaft, a plate mounted to its bottom end, and a sensor body also mounted to the bottom of the shaft, independently of the plate. A tine tip projects below the sensor body. The sensor body has compression sensors and shear sensors. The user pushes down on the shaft. The tine tip penetrates the ground until the plate abuts the surface. Continued pushing leads to a compression reading. The user then pushes the...

An apparatus and process for determining whether a fault has occurred in a welding process while the process is under way. The invention is applicable to welding and cutting processes where there is an arc plasma, such as gas-metal arc welding, tungsten-inert gas welding, pulsed welding, resistance welding and submerged welding. It involves sampling welding voltage and welding current to provide first and second signals, generating artificial third signals from these dependent on values of the f...

A method of measuring oestrogen or progesterone receptor (ER or PR) comprises identifying in histopathological specimen image data pixel groups indicating cell nuclei, and deriving image hue and saturation. The image is thresholded using hue and saturation and preferentially stained cells identified. ER or PR status is determined from normalised average saturation and proportion of preferentially stained cells. A method of measuring C-erb-2 comprises correlating window functions with pixel sub-g...