Remarks on some vacuum solutions of scalar-tensor cosmological models

We present a class of exact vacuum solutions corresponding to de Sitter and warm inflation models in the framework of scalar-tensor cosmologies. We show that in both cases the field equations reduce to planar dynamical systems with constraints. Then, we carry out a qualitative analysis of the models by examining the phase diagrams of the solutions near the equilibrium points.Comment: 12 pages, 4 figures. To be published in the Brazilian Journal of Physic

Conditional linearizability criteria for a system of third-order ordinary differential equations

We provide linearizability criteria for a class of systems of third-order ordinary differential equations (ODEs) that is cubically semi-linear in the first derivative, by differentiating a system of second-order quadratically semi-linear ODEs and using the original system to replace the second derivative. The procedure developed splits into two cases, those where the coefficients are constant and those where they are variables. Both cases are discussed and examples given

Single Photon Avalanche Diode with Monte Carlo Simulations: PDP, Jitter and Quench Probability

International audienc

Design and performance of the main amplifier system for the National Ignition Facility

This paper describes the design and performance of flashlamp-pumped, Nd:glass. Brewster-angle slab amplifiers intended to be deployed in the National Ignition Facility (NIF). To verify performance, we tested a full-size, three-slab-long, NIF prototype amplifier, which we believe to be the largest flashlamp-pumped Nd:glass amplifier ever assembled. Like the NIF amplifier design, this prototype amplifier had eight 40-cm-square apertures combined in a four-aperture-high by two-aperture-wide matrix. Specially-shaped reflectors, anti-reflective coatings on the blastshields, and preionized flashlamps were used to increase storage efficiency. Cooling gas was flowed over the flashlamps to remove waste pump heat and to accelerate thermal wavefront recovery. The prototype gain results are consistent with model predictions and provide high confidence in the final engineering design of the NIF amplifiers. Although the dimensions, internal positions, and shapes of the components in the NIF amplifiers will be slightly different from the prototype, these differences are small and should produce only slight differences in amplifier performanc

Resource Efficiency in Practice – Closing Mineral Cycles : Final report

Nutrients such as nitrogen (N), phosphorus (P) and potassium (K) are essential elements for living organisms, including plants, animals and bacteria. They are used as fertilisers in agriculture to guarantee high yields and quality products. However, the increasing demand not only in food production, but also in feed, fibre and fuel, has resulted in an increasing use of N, P and K. The depletion of non-renewable resources (such as mined phosphates rock) jeopardises the viability of the current agricultural production systems in the long term. In addition, while progress has been made towards sustainable agricultural practices, a number of inefficiencies are observed in nutrient use which can lead to the degradation of land, soil and water resources. Ultimately, this can impede well-being and economic growth from farm level to EU level. In this context, the first objective of the project \u201cResource efficiency in practice \u2013 Closing mineral cycles\u201d was to identify the most promising measures at regional and farm levels, in particular in nutrient saturated areas, to improve the use of nutrients and to reduce their negative impacts. The second objective was to communicate the information gathered to farmers, farmers\u2019 associations, and regional decision-makers in an educational style to empower them to take action at their level. Communication channels included leaflets, a dedicated website (http://mineral-cycles.eu) and four regional conferences, as well as a final conference in Brussels