The influence of environmental temperatures on the composition of milk of the dairy cow

Digitized 2007 AES.Includes bibliographical references (pages 47-50)

Spallation-Fission Competition in Heaviest Elements; Helium IonInduced Reactions in Plutonium Isotopes

Excitation functions have been determined for the spallation and fission reactions induced in plutonium isotopes by 20 to 50 Mev helium ions. The method employed consisted of cyclotron bombardments of plutonium oxide followed by the chemical isolation and alpha or beta counting of radioactive reaction products. Formation cross sections are given where possible for the curium and americium spallation products corresponding to ({alpha},n), ({alpha},2n), ({alpha},3n), ({alpha},4n), ({alpha}5n), ({alpha},p), ({alpha},pn or d), ({alpha},p2n or t), and ({alpha},p3n) reactions in Pu{sup 238} , Pu{sup 239}, and Pu{sup 242}. Fission yield curves and fission cross sections for Pu{sup 238} and Pu{sup 239} serve to define the characteristics of the ({alpha},f) reaction for plutonium isotopes. Chemical procedures are outlined for the separation of both spallation and fission product elements in a sequence of operations performed on the entire dissolved target

Lawson criterion for ignition exceeded in an inertial fusion experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion