Alpha particle types: eventually named alpha, beta, and gamma by Rutherford, based on penetration of objects and deflection by a magnetic field. Alpha rays were defined by Rutherford as those having the lowest penetration of ordinary objects. Rutherford's work also included measurements of the ratio of an alpha particle's mass to its charge, which led him to the hypothesis that alpha particles were doubly charged helium ions (later shown to be bare helium nuclei). In 1907, Ernest Rutherford and Thomas Royds finally proved that alpha particles were indeed helium ions. To do this they allowed alpha particles to penetrate a very thin
Yeast assimilable nitrogen tend to progress at a faster rate, requiring more nitrogen than longer, cooler fermentation. Also the amount of oxygen exposure will influence the rate of nitrogen uptake by the yeast with wine fermented in complete anaerobic conditions (such as many white wines in stainless steel tanks) requiring less nitrogen than wines fermented in barrels or open top fermentors. The suggested range given by enologists varies from 150 mg/l YAN to 400 mg of nitrogen per liter. Some studies have shown that maximum fermentation rates can be achieved with YAN in the 400 to 500 mg N/L range. However, not all