Detection of bump-on-tail reduced electron velocity distributions at the electron foreshock boundary

Reduced velocity distributions are derived from three-dimensional measurements of the velocity distribution of electrons in the 7 to 500 eV range in the electron foreshock. Bump-on-tail reduced distributions are presented for the first time at the foreshock boundary consistent with Filbert and Kellogg's proposed time-of-flight mechanism for generating the electron beams. In a significant number of boundary crossings, bump-on-tail reduced distributions were found in consecutive 3 sec measurements made 9 sec apart. It is concluded that, although the beams are linearly unstable to plasma waves according to the Penrose criterion, they persist on a time scale of 3 to 15 sec

Efficiency of use of pigs, bred in Lithuania, in hybridization system

Boars of Landrace, Duroc and Pietrain breeds had positive influence on the vitality of delivered hybrids. Better growth of hybrids is defined in these combinations, where boars of Duroc breed were used. According to the data of Piglog 105, crossbreds of Yorkshire and Pietrain distinguished by the biggest muscularity (59.0%), and the least muscularity was indicated among crossbreds of Yorkshire, Landrace and Duroc (three breeds) and of Lithuanian White and Landrace (53.5 and 54.4% respectively). Lowest muscularity was indicated namely among hybrids of the combinations, having the highest daily gain. Combinations of hybridization, recommended in Lithuania, are presented in the table 1

A Playful Life Cycle Assessment of the Environmental Impact of Children\u27s Toys

Toys aid in children’s progression through developmental stages, yet toy production has an environmental impact. This study is the first comparative life cycle assessment of three children’s toys. A life cycle assessment quantifies the impact of an item in comparable impact categories (i.e. global warming potential in kg CO2 equivalents). In this study, we use open LCA to compare toy impact from production to use. The results indicate that the plastic polybutylene carried the highest impact in terms of global warming potential for our predominantly plastic toy. The addition of a battery to the plush dog increased the toy’s eutrophication potential by a factor of 2.398. These results indicate some of the materials that consumers may want to avoid or minimize when purchasing toys

Test particle propagation in magnetostatic turbulence. 1. Failure of the diffusion approximation

The equation which governs the quasi-linear approximation to the ensemble and gyro-phase averaged one-body probability distribution function is constructed from first principles. This derived equation is subjected to a thorough investigation in order to calculate the possible limitations of the quasi-linear approximation. It is shown that the reduction of this equation to a standard diffusion equation in the Markovian limit can be accomplished through the application of the adiabatic approximation. A numerical solution of the standard diffusion equation in the Markovian limit is obtained for the narrow parallel beam injection. Comparison of the diabatic and adiabatic results explicitly demonstrates the failure of the Markovian description of the probability distribution function. Through the use of a linear time-scale extension the failure of the adiabatic approximation, which leads to the Markovian limit, is shown to be due to mixing of the relaxation and interaction time scales in the presence of the strong mean field

Test particle propagation in magnetostatic turbulence. 3: The approach to equilibrium

The asymptotic behavior, for large time, of the quasi-linear diabatic solutions and their local approximations is considered. A time averaging procedure is introduced which yields the averages of these solutions over time intervals which contain only large time values. A discussion of the quasi-linear diabatic solutions which is limited to those solutions that are bounded from below as functions of time is given. It is shown that as the upper limit of the time averaging interval is allowed to approach infinity the time averaged quasi-linear diabatic solutions must approach isotropy (mu-independence). The first derivative with respect to mu of these solutions is also considered. This discussion is limited to first derivatives which are bounded functions of time. It is shown that as the upper limit of the time averaging interval is allowed to approach infinity, the time averaged first derivative must approach zero everywhere in mu except at mu = 0 where it must approach a large value which is calculated. The impact of this large derivative on the quasi-linear expansion scheme is discussed. An H-theorem for the first local approximation to the quasi-linear diabatic solutions is constructed. Without time averaging, the H-theorem is used to determine sufficient conditions for the first local approximate solutions to asymptote, with increasing time, to exactly the same final state which the time averaged quasi-linear diabatic solutions must approach as discussed above

Test particle propagation in magnetostatic turbulence. 2: The local approximation method

An approximation method for statistical mechanics is presented and applied to a class of problems which contains a test particle propagation problem. All of the available basic equations used in statistical mechanics are cast in the form of a single equation which is integrodifferential in time and which is then used as the starting point for the construction of the local approximation method. Simplification of the integrodifferential equation is achieved through approximation to the Laplace transform of its kernel. The approximation is valid near the origin in the Laplace space and is based on the assumption of small Laplace variable. No other small parameter is necessary for the construction of this approximation method. The n'th level of approximation is constructed formally, and the first five levels of approximation are calculated explicitly. It is shown that each level of approximation is governed by an inhomogeneous partial differential equation in time with time independent operator coefficients. The order in time of these partial differential equations is found to increase as n does. At n = 0 the most local first order partial differential equation which governs the Markovian limit is regained

Compact oscillons in the signum-Gordon model

We present explicit solutions of the signum-Gordon scalar field equation which have finite energy and are periodic in time. Such oscillons have a strictly finite size. They do not emit radiation.Comment: 12 pages, 4 figure