materials and equipment
DRAWING SYMBOLS
Ten sheets of architectural symbols have been added to the Letter-Press range of dry-transfer lettering.
The 320- by 400-mm. sheets offer, in plan and elevation, symbols that in- clude trees, furniture, domestic equip- ment, vehicles, people and the metric- change symbol. A thin transparent film, incorporated to ensure complete transfer and to increase rub resistance, backs each symbol.
Symbols are laid face down on the drawing and their backs rubbed with
Mecanorma symbols
either a plastic spatula or ball-point pen to effect transfer. They are heat resistant.
The makers are Mecanorma, 78 Le Perray-en-Yvelines, France. Distribut- ors include: International Trading Agency, Hong Kong; Mimreps, Kuala Lumpur; and D.H.A. Siamwalla Ltd., Bangkok.
MEASURING
Nuclear density or alternatively the moisture content of surfaces such as hot asphalt or the compacted base course of roads can be gauged by a new portable instrument called the Hidrodensimeter HDM4.
Tests have shown that many soils for road-building need be rolled only a few times to reach an acceptable de- gree of compaction. Cost in use of this non-destructive testing apparatus is claimed to be about one third that of equipment giving comparable ac- curacy.
The makers, Tellurometer (UK) Ltd., Oakcroft Road, Chessington, Surrey, UK, have also introduced an instrument, the MA 100, which can measure distance to an accuracy of 1,5
Far East BUILDER, September 1970
Hidrodensimeter HDM 4
mm over distances of as much as 2 km. It is battery operated, employs inte- grated circuits and a Gallium Arsenide diode to produce a continuous carrier wave of infra-red radiation modulated at a frequency of 75 MHz.
A small telescope is used to aim the beam of radiation at the target point where a prism assembly reflects the beam back to the unit. The reflected
beam is a replica of the original modu- lating waveform, but is delayed on its phase by an amount proportional to the distance travelled. This distance is displayed on a 4-digit read-out. Appli- cations include surveys for large con- struction work, and measurement of structures such as dams to assess creep.
AERIAL SURVEYS
A method of aerial surveying which uses a new infra-red detector to pro- duce a thermal image of the ground below is now available world-wide as a commercial service from Fairey Surreys Ltd., Reform Road, Maidenhead, Berks., UK.
The method produces a picture made up of variations in temperature as compared with conventional photo- graphy which records variations in light and shade. Objects hotter or cold- er than their surroundings can there- fore be detected.
Applications include plotting un- derground pipelines, subterranean streams, and effluent flow in rivers; determining soil properties; and moni- toring power transmission lines for overheating. Objects invisible to con-
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ventional photography overgrown entrances to mine shafts, for example - can be detected by comparing the thermal image with conventional aerial photographs taken at the same time. Any anomalies between the two can then be investigated on the ground to determine the cause.
The equipment used, the new EMI Airscan, can detect temperature dif- ferences as small as 0.3 deg.C., and re- solve objects 1 ft. 6 in. across from a height of 1,000 ft. An advance claimed over earlier thermal imaging systems is that the output is recorded on video- tape (instead of by photographing the image as it appears on a cathode ray tube) so that the results of a particular survey can be played back repeatedly for subsequent study.
DRAWING EQUIPMENT T
Designed to provide facilities for either general-purpose use or drawing work, the RA 020 drawing desk in- corporates a loose top panel which can be turned over to reveal an A2-size drawing board fixed to its underside by means of a folding metal stand.
This metal stand allows the board to be folded flat for storage or raised to any one of several angles up to ap- proximately 70 deg.
British Thornton work station RA020
The beech-wood framework of the bench measures 1.17 m. long by 560 mm. wide by 700 mm. high and is pro- tected by a layer of scratch- and stain- resistant lacquer. Its two side leg units detach easily.
A layer of dark-green plastic lami- nate protects the top panel, and a slid- ing drawer mounted under the fixed section of the top panel provides a use. ful storage area. Made of grey thermo-
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