Drop Counter Research Articles

An Electronic Drop Counter for Ion Exchange Chromatography

An Electronic Drop Counter for Ion Exchange Chromatography

An Improved Method for Drop Recording

A simple, trouble-free method for counting and recording drops of fluids in biological experiments is described.

Light transmittance as a measure of interfacial area in liquid‐liquid dispersions

AbstractInterfacial area in liquid‐liquid systems has been measured photographically. Precision and accuracy of the method have been shown to be better than 10%. To avoid tedium of counting drops, a simple light probe of easily reproducible design has been developed to measure the light transmission through the dispersions formed. A correlation of light transmittance with interfacial area is presented and its usefulness and limitations are discussed.

C. Photometric measurement of ionization in cloud chambers

Abstract It has been found possible to measure the ionization of a cloud chamber track by photometry of the chamber photograph. The method is applicable to tracks, the photographic images of which consist of unresolved drop images. Its application does not interfere with accurate measurement of the magnetic rigidity of the particle causing the track. The use of the method has been investigated by studying tracks in a typical chamber and is illustrated by mass measurements on 3 K-mesons. The relative merits of this photometric method and the drop counting method of measuring ionization are discussed.

A note on a simple universal fluid drop counter

A simple, easily constructed, economical fluid drop counter is described. Although suitable for most perfusion experiments, it has been found to be particularly efficacious for use with fluids of low electrolyte content such as saliva.

Ionization by Relativistic -Mesons in Oxygen

The specific ionization in oxygen near atmospheric pressure has been measured over the momentum range 3 × 108 eV/c<p<3 × 1010 eV/c, excluding collisions involving energy transfers greater than 1 keV. The measurement was based upon drop counts in the positive ion column of tracks in a cloud chamber independent of the system used to measure momentum. Modification of ionization due to polarization phenomena is shown to become important at momenta greater than about 6 × 109 eV/c.

核心計の改良

Improvement of the nucleus-counter of Aitken type was done to use it in routine works.The principal points of impyovement are as follows:(1) A rubber sheet was used at the pump, just as in Wilson's cloud chamber, to prevent the leakage of air.(2) For counting drops, a microscope was used instead of a lens. It made counting easier to all observers, and moreover we could count drops, with another eye-piece of different power of magnification, to a larger extent of the number of drops without using a dilution-pump.(3) As a dilution-pump, Scholz's type was adopted. We could measure necessary volume of air more accurately by this pump than by Aitken's one.(4) No leakage of air occurred through the pump in each stage of successive expansions of the same sample of air, thus it enabled us to measure neuclei-spectrums using various ratio of expansions.(5) According to the result of investigations of F. J. Scrase, the stirring-vane was removed from this chamber.(6) This apparatus was tested at various heights of Mt. Fuji both in summer and in winter seasons, and proved its excellent functions.

The Relativistic Increase in Ionization of High Energy Electrons and Mesotrons

The ionization by electrons and mesotrons has been determined from drop counts along diffuse tracks that were photographed in a Wilson cloud chamber. It is believed that uncertainties in condensation efficiency and curvature do not contribute significantly to the errors. The relativistic increase in ionization for electrons agrees with theory but the average ionization of all penetrating particles is less than that predicted for a purely mesotronic composition. The minimum ionization by a singly-charged particle is 38 ion pairs per cm in dry air at N.P.T. when energy transfers greater than 600 ev are excluded.

A RELATIVE CENSUS METHOD FOR BROWN RATS (RATTUS NORVEGICUS)

A USEFUL summary of census methods for mammals has been given by Dice1. Apart from those which involve killing the animals the following types have been used: counts of droppings, tracks, homes, or the animals themselves ; live trapping followed by marking and releasing. Live census methods for rats have not, except in ship deratization work, been well developed along these or other lines. Droppings are the most reliable signs used by inspectors on board ship2; and their estimates of infestation usually check very closely with numbers found dead after fumigation3. The operation, however, is a highly skilled one, and since allowance must be made for the type of food and rate of desiccation of the droppings, probably cannot well be applied elsewhere. Tracks and runways in mud, dust, snow, etc., show rat distribution but give little indication of numbers. A white powder such as plaster-of-Paris is useful for showing up footprints. Homes. In habitats such as hedge banks a count of holes may be made; but in buildings the number is seldom related to the density of the rats. Nests of Rattus rattus subspecies can be seen in the trees in Hawaii4,5 but nests of brown rats are not as a rule easily found. Brown rats themselves are largely nocturnal, and no representative fraction of the population is likely to be seen (on ships not more than one in twenty)2 except by destruction of the habitat or by bolting the rats with gas or ferrets. (The method is not good in premises such as shops.) Live trapping, marking and releasing has been carried out at this Bureau, but involves a good deal of work and technical difficulty. Other signs of the presence of rats include their odour, damage to food and structures, the black, oily smear left along runways and an occasional dead rat2.

A Telephonic Drop Counter

A Telephonic Drop Counter