Search results for "SAIL"

Comparison of methods to estimate LAI from remote sensing in maize canopies by inversion of 1-D and 3-D models

2009

The inversion of canopy reflectance models is a procedure widely employed for the retrieval of LAI from remote sensing. However the accuracy of the estimates depends on a range of factors, most notably the realism of the canopy representation of the models employed and the a priori knowledge of some vegetation characteristics. The objective of the present work was to compare the performances and the operational limitations of the use of two contrasting type of radiative transfer models: a classical one-dimensional canopy reflectance model, PROSPECT+SAIL (PROSAIL) and a three-dimensional dynamic maize model (Lopez-Lozano et al., 2007) having greater realism in the description of the canopy s…

Periodic Motion for an Imperfect Solar Sail Near an Asteroid

2014

In this paper we consider the Hill 3-body problem with the extra effect of the solar radiation pressure as a model for the motion of a solar sail close to an asteroid. To model the sail’s acceleration, we include both reflectivity and absorption of the sail’s material. We describe the most relevant dynamical properties of the system for different reflectivity and absorption coefficients as well as different fixed sail orientations. We show families of periodic orbits, describe how they relate to the parameters of the sail and discuss their stability.

E-sail test payload of the ESTCube-1 nanosatellite

2014

The scientific mission of ESTCube-1, launched in May 2013, is to measure the electric solar wind sail (E-sail) force in orbit. The experiment is planned to push forward the development of the E-sail, a propulsion method recently invented at the Finnish Meteorological Institute. The E-sail is based on extracting momentum from the solar wind plasma flow by using long thin electrically charged tethers. ESTCube-1 is equipped with one such tether, together with hardware capable of deploying and charging it. At the orbital altitude of ESTCube-1 (660–680 km) there is no solar wind present. Instead, ESTCube-1 shall observe the interaction between the charged tether and the ionospheric plasma. The E…

Veleggiare in gara

2015

Regulation of sailing sports during a race and civil liability of partecipants have a specific rule within the legal order of maritime law. The article focuses on pleasure navigation for sportive reasons, the level of sailing risk accepted by all partecipants, the damages occurring during a sailing race.

A reverse engineering approach to measure the deformations of a sailing yacht

2016

In this work, a multidisciplinary experience, aimed to study the permanent deformations of the hull of a regatta sailing yacht is described. In particular, a procedure to compare two different surfaces of the hull of a small sailing yacht, designed and manufactured at the University of Palermo, has been developed. The first one represents the original CAD model while the second one has been obtained by means of a reverse engineering approach. The reverse engineering process was performed through an automatic close-range photogrammetry survey, that has allowed to obtain very accurate measures of the hull, and a 3D modelling step by the well-known 3D computer graphics software Rhinoceros. The…

A new methodology to evaluate the flying shape of a sail

2013

Primitives detection by a discrete and non linear approach : application to the detection and caracterization of interest points for 3D meshes

2010

This manuscript is dedicated to the detection and caracterization of interest points for 3D meshes. First of all, we show the limitations of the curvature measure on sharp edges, the measure usually used for the analysis of meshes. Then, we present a generalization of the SUSAN operator for meshes, named SUSAN-3D. The saliency measure proposed quantify the local variation of the surface and classify directly the analysed vertices in five classes: salient, crest, flat, valley and cavity. The meshes under consideration are manifolds and can be closed or non-closed, regulars or irregulars, dense or not and noised or not. The accuracy of the SUSAN-3D operator is compared to two curvature operat…

Stratis il marinaio, Mattia Pascal e gli altri: nomi nell’opera di Ghiorgos Seferis

2017

Ghiorgos Seferis (1900-1971), Nobel prize for literature in 1963, is one of the most significant poets of modern Greece. In his work he reconciles reminiscences of classical Greece with the most salient concern of contemporary poetry. Like many other writers of the twentieth and twenty-first centuries, Ghiorgos Seferis used various heteronyms in the course of his life. The most significant are ‘Stratis the sailor’ and ‘Mattia Pascal’. Both are rooted in the biographical events of the poet, as well as in his many cultural experiences.

List of Russian sailing vessels of 75 tons and upwards, registered in the ports of the Baltic sea

1905

Titullapa angļu valodā, teksts vācu un angļu valodā

How to Defend in Water: The French Sailors' Surprising Method of Self-defence (1921)

2021

No abstract