Method and means for helium/hydrogen ratio measurement by alpha scattering

An apparatus for determining helium to hydrogen ratios in a gaseous sample is presented. The sample is bombarded with alpha particles created by a self contained radioactive source and scattering products falling within a predetermined forward scattering angular range impact a detector assembly. Two detectors are mounted in tandem, the first completely blocking the second with respect to incident scattering products. Alpha particle/hydrogen or alpha particle/helium collisions are identified by whether scattering product impacts occur simultaneously in both detectors or only in the first detector. Relative magnitudes of the two pulses can be used to further discriminate against other effects such as noise and cosmic ray events

The Corona Voltmeter and the Electric Strength of Air

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The effect of two distinct fast time scales in the rotating, stratified Boussinesq equations: variations from quasi-geostrophy

This is the author accepted manuscript. The final version is available from Springer via the DOI in this record.Inspired by the use of fast singular limits in time-parallel numerical methods for a single fast frequency, we consider the limiting, nonlinear dynamics for a system of partial differential equations when two fast, distinct time scales are present. First order slow equations are derived via the method of multiple time scales when the two small parameters are related by a rational power. We find that the resultant system depends only on the relationship of the two fast time-scales, i.e. which fast time is fastest? Using the theory of cancellation of fast oscillations, we show that with the appropriate assumptions on the nonlinear operator of the full system, this reduced slow system is exactly that which the solution will converge to if each asymptotic limit is considered sequentially. The same result is also obtained via the method of renormalization. The specific example of the rotating, stratified Boussinesq equations is explored in detail, indicating that the most common distinguished limit of this system – quasi-geostrophy, is not the only limiting asymptotic system.We wish to thank the 2 anonymous referees whose comments significantly enhanced the presentation and scope of this article. J. P. W. would like to thank A.Larios, K. Julien, G. Chini, and A. Farhat for various discussions that prompted and motivated this work as well as generous support from the Mathematics Department of Brigham Young University. All of the authors wish to acknowledge the DOE LANL/LDRD program for support, as well as the hospitality of the Courant Institute of New York University where some of this work was completed. Wingate also wishes to thank the University of Exeter for support during the completion of this manuscript

Micromagnetic simulations of interacting dipoles on a fcc lattice: Application to nanoparticle assemblies

Micromagnetic simulations are used to examine the effects of cubic and axial anisotropy, magnetostatic interactions and temperature on M-H loops for a collection of magnetic dipoles on fcc and sc lattices. We employ a simple model of interacting dipoles that represent single-domain particles in an attempt to explain recent experimental data on ordered arrays of magnetoferritin nanoparticles that demonstrate the crucial role of interactions between particles in a fcc lattice. Significant agreement between the simulation and experimental results is achieved, and the impact of intra-particle degrees of freedom and surface effects on thermal fluctuations are investigated.Comment: 10 pages, 9 figure

Dynamical Spin Response Functions for Heisenberg Ladders

We present the results of a numerical study of the 2 by L spin 1/2 Heisenberg ladder. Ground state energies and the singlet-triplet energy gaps for L = (4-14) and equal rung and leg interaction strengths were obtained in a Lanczos calculation and checked against earlier calculations by Barnes et al. (even L up to 12). A related moments technique is then employed to evaluate the dynamical spin response for L=12 and a range of rung to leg interaction strength ratios (0 - 5). We comment on two issues, the need for reorthogonalization and the rate of convergence, that affect the numerical utility of the moments treatment of response functions.Comment: Revtex, 3 figure

Nitrous oxide emission from a range of land uses across Europe

International audienceThe results of a literature study examining quantitative estimates of N2O emission rates are presented for a range of land-uses across Europe. The analysis shows that the highest N2O emission rates are for agricultural lands compared to forests and grasslands. The main factors regulating these rates are available mineral nitrogen, soil temperature, soil water content and the available labile organic compounds. These controls operate across different time-scales, all must exceed a certain threshold for N2O emission to occur. The results support the need for an emission factor function of land-use and climate within models describing nitrogen dynamics in catchments. This would allow the assessment of the net N2O emission within catchments in terms of current levels and potential changes associated with climate variability, climate change and land use change. Keywords: nitrous oxide, soil water content, inorganic N, soil temperature, ecosystems, land-use management, soil typ

‘Think Aloud’: Towards a framework to facilitate reflective practice amongst rugby league coaches.

This study aimed to design, implement and evaluate a protocol encompassing Think Aloud (TA) as a technique to facilitate reflection-in-action and delayed reflection-on-action to aid coach learning. Six British, male rugby league coaches, who reported little previous exposure to reflective practice, consented to participate. Participants were: (a) instructed on how to engage in TA; (b) observed in practice using TA; (c) provided with individual support on delayed reflective practice on their first coaching session and use of TA; (d) observed in practice using TA a second time; and (e) engaged in a social validation interview regarding their experiences of TA. Analysis of in-action verbalizations revealed a shift from descriptive verbalizations to a deeper level of reflection. Both immediate and post eight week social validation interviews revealed that coaches developed an increased awareness, enhanced communication, and pedagogical development. The participants also recommended that TA can be a valuable tool for: (a) collecting in-event data during a coaching session; and (b) developing and evidencing reflection for coaches. Future recommendations were also provided by the participants and consequently, this study offers a unique technique to reflective practice that has the potential to meet the learning development needs of coaches

The Beagle 2 optical microscope

Introduction to the Beagle2 optical microscope

A Composite Chiral Pair of Rotational Bands in the odd-A Nucleus 135Nd

High-spin states in 135Nd were populated with the 110Pd(30Si,5n)135Nd reaction at a 30Si bombarding energy of 133 MeV. Two Delta(I)=1 bands with close excitation energies and the same parity were observed. These bands are directly linked by Delta(I)=1 and Delta(I)=2 transitions. The chiral nature of these two bands is confirmed by comparison with three-dimensional tilted axis cranking calculations. This is the first observation of a three-quasiparticle chiral structure and established the primarily geometric nature of this phenomenon.Comment: 10 pages, 5 figures (1 in color), 1 table, submitted to Physics Review Letters, written in REVTEX4 forma

Synthetic Quantum Systems

So far proposed quantum computers use fragile and environmentally sensitive natural quantum systems. Here we explore the new notion that synthetic quantum systems suitable for quantum computation may be fabricated from smart nanostructures using topological excitations of a stochastic neural-type network that can mimic natural quantum systems. These developments are a technological application of process physics which is an information theory of reality in which space and quantum phenomena are emergent, and so indicates the deep origins of quantum phenomena. Analogous complex stochastic dynamical systems have recently been proposed within neurobiology to deal with the emergent complexity of biosystems, particularly the biodynamics of higher brain function. The reasons for analogous discoveries in fundamental physics and neurobiology are discussed.Comment: 16 pages, Latex, 1 eps figure fil