Detached leaves of Valencia oranges, Citrus sinensis Osbeck, emanated ethylene at markedly higher rates and contained more endogenous ethylene when placed under water stress at 55% relative humidity than when placed in water-saturated air. Water stress induced defoliation from detached branches. Relieving the water stress of such leaves by transfer to a mist chamber resulted in lowering of the ...

Anomalous emanation of radon (222Rn) was observed preceding large earthquakes and is considered to be linked to preseismic electromagnetic phenomena (e.g. great changes of atmospheric electric field and ionospheric disturbances). Here we analyze atmospheric radon concentration and estimate changes of electrical conditions in atmosphere due to preseismic radon anomaly. The increase of radon eman...

In our studies on the radiochemical reaction effeeted by the radiations (beta and gamma) from radium emanation in which enzymes are inactivated we have stated that in a given system the chemical change is a function of the product of two variables; namely, the average amount of emanation present, Eo, and time, t. Theproduct of these two variables has been equated to a single variable, W, for wh...

This report presents a brief review as well as some theoretical background on radon (^Rn) emanation methods from solid samples. This is followed by a description of an experimental apparatus built at the Elliot Lake Laboratory. (Mining Research Laboratory. CANMET, E.M.R.) to measure the ^Rn emanation rate from ^Ra-bearing solid materials by the vacuum emanation method. Experimental data are pre...

Radon emanation rates from 48 concrete blocks have been monitored throughout a period in excess of 1 yr. These blocks have been produced for three distinct mixes of materials, i.e. mix A with 25% by weight substitution of type A pulverized fuel ash (PFA), mix B with 25% by weight substitution of type B PFA and mix C without PFA. Each mix is represented by four sets of concrete blocks with curin...

The national standard for radon (Rn) measurements in the United States is based on Standard Reference Materials (SRMs) prepared at the National Institute of Standards and Technology (NIST), Gaithersburg, MD. NIST radon standards are hermetically sealed polyethylene capsules, filled with radium (Ra) solution. In preparation of standard reference materials for Rn, it is necessary to understand pr...

The radon isotopes (Rn-222 and Rn-220) and their progenies are responsible for more than 50% of natural radiation dose and the second leading factor in the case of the development of lung cancer after smoking [1]. Rn-222 (radon) and Rn-220 (thoron) are generated in crustal materials from their natural Ra-226 (U-238 decay series) and Ra-224 (Th-232 decay series) content, respectively. As a resul...

The fraction of radon atoms generated from radium decay that are released from into a rock or soil pore space is defined as the radon emanation coefficient, or emanating power, of the material. The emanation coefficient of rocks and soils typically varies between about 0.05 and 0.70, and an average value for soils is probably between 0.20 and 0.30. Geologic, pedologic, and climatic factors, inc...