Automated complex “Miсron” for determining measurement error of microwave radio interferometers

The technique of radiointeroferometric measurements is presented and a theoretical estimate of the measuring error the reflecting surface movement is given. The movement are measured with microwave radio interferometers. The automated complex “Miсron” design and principle of operation are described. The complex is intended for experimental determination of the error in measuring the movement of a reflecting surface, as well as for primary and periodic verification of microwave radio interferometers. The complex “Miсron” includes a measuring instrument of the 3rd accuracy class – an incremental linear displacement transducer LIR-7A, which measures the reflecting surface movement of the test object. For the “Miсron” complex verification of the longitudinal movement measuring line is provided, which makes it possible to verify the LIR-7A transducer without dismantling it. Planeparallel gauge blocks or similar standards can be used as the initial standard for verification. The comparison of the movement measured values determined during verification and obtained by an alternative method providing the required accuracy of radio interferometric measurements is carried out.

High-resolution studies of growth oscillations during stem elongation

A linear-displacement transducer system coupled to a signal differentiator was used to obtain continuous high-resolution measurements of stem elongation rate in etiolated Sinapis alba L., Raphanus sativus L., Cucumis sativus L., Helianthus annuus L., and Avena sativa L. seedlings. The sensitivity of the measuring system was sufficient to resolve changes in length of ± 0.2 μm and changes in growth rate of ±3 μm h−1. Under constant conditions of darkness, 25 ± 0.1 °C, 100% relative humidity, and buffered root pH, the elongation rate of etiolated seedlings was not constant but oscillated in most of the seedlings studied. Large amplitude, long (> 45 min) period oscillations were common in all species except S. alba. Visual observations using a green safelight indicated that such oscillations were artifacts generated by nutational bending. Sustained, short (< 45 min) period oscillations were common in all species except H. annuus. In dicots, short period oscillations were not caused by bobbing of the hypocotyl hook but originated lower in the hypocotyl axis. Temperature shifts changed the frequency of short period oscillation with a Q10 > 2. The results suggest that the short period oscillations are not due to local environmental fluctuations but are spontaneously produced by a seedling undergoing synchronized variations in the rate of cell elongation.

AUTOMATED RECORDING OF FRUIT PRESSURE TESTS

Automated recording of Magness-Taylor fruit pressure tester values is accomplished by coupling the indicator slide to a linear displacement transducer and a microprocessor-controlled printer. After each pressure test, a transducer-induced voltage value is recorded and stored when a microswitch is activated by the manual slide return mechanism. Upon command, the recorder totals and averages all stored values. This accessory doubles the output of fruit pressure tests per man hour without loss of accuracy.