A VERSATILE RECORDING POTENTIOMETER

A RECORDING POTENTIOMETER FOR USE IN PHYSIOLOGICAL INVESTIGATIONS

PLANT PHYSIOLOGY ◽

10.1104/pp.12.2.487 ◽

1937 ◽

Vol 12 (2) ◽

pp. 487-498 ◽

Cited By ~ 3

Author(s):

R. H. Wallace

Keyword(s):

Recording Potentiometer

Get full-text (via PubEx)

Freezing Point Determination in Immature Stages of Insects

The Canadian Entomologist ◽

10.4039/ent96158-1 ◽

1964 ◽

Vol 96 (1-2) ◽

pp. 158-158 ◽

Cited By ~ 9

Author(s):

C. R. Sullivan ◽

G. W. Green

Keyword(s):

Cold Hardiness ◽

Freezing Point ◽

Visual Observation ◽

Freezing Process ◽

Immature Stages ◽

Filter Paper Disc ◽

Recording Potentiometer ◽

Binocular Microscope ◽

The Moment ◽

Freezing Chamber

Conventional and modified methods of obtaining supercooling points of immature stages of insects have been utilized in studies of the cold-hardiness of the European pine shoot moth and the European pinesawfly. A method has been developed to permit visual observation of the freezing process of more than one specimen at a time. A freezing chamber consisting of a hole one inch in depth and one-half inch in diameter is located in the upper end of an aluminum rod partially submerged in a dry ice-alcohol mixture. A small filter paper disc, used as the insect platform, rests upon a #40 copper-constantan thermocouple located near the base of the freezing chamber. The thermocouple enters the chamber through a hole in the wall after several circuits around the circumference of the rod to prevent temperature anomalies attributable to thermal conduction within the wire. The thermocouple is connected to a sensitive recording potentiometer. The wall of the freezing chamber is blackened to prevent reflection of light from obscuring the view of the freezing process, through a binocular microscope mounted above the freezing chamber. The moment of freezing is readily recorded on the temperature trace provided by the potentiometer. At a cooling rate of approximately 5°F. per minute, a correction factor of 2.5°F. must be added to the indicated freezing point to obtain the actual temperature at the surface of the platform. When this correction is applied, the results provide data applicable to statistical analysis of freezing point determinations.

Get full-text (via PubEx)

Intensities in Raman spectra III. A photoelectric recording Raman spectrometer for intensity measurements

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1956.0171 ◽

1956 ◽

Vol 237 (1209) ◽

pp. 186-196 ◽

Cited By ~ 7

Keyword(s):

Light Source ◽

High Intensity ◽

Room Temperature ◽

Recording System ◽

Photoelectric Recording ◽

Intensity Measurements ◽

Wide Range ◽

Recording Potentiometer ◽

Phase Sensitive ◽

High Intensity Light

A description is given of a Raman apparatus designed primarily for intensity measurements by direct photo-electric recording. A special feature is a high- intensity light source with four Toronto-type mercury arcs. It is possible to use a variety of sample volumes and to make measurements on samples over a wide range of temperatures both above and below room temperature. Semi-quantitative polarization measurements can also be made. The recording system uses an E. M. I. eleven-stage photomultiplier cell with a. c. amplification at 285 c/s, followed by rectification in a phase-sensitive homodyne circuit. The output is fed to a Cambridge recording potentiometer. Details of calibration for intensity measurements are given and sample records are shown illustrating the various applications of the apparatus.

Get full-text (via PubEx)