Report of the Horse Mackerel Exchange and Workshop 2006

Following a recommendation from PGCCDBS, a workshop on age calibration of horse mackerel was carried out. The workshop was preceded by an exchange. The objectives were: to improve the quality of horse mackerel readings by international calibration. In particular, attempt to resolve the observed differences between countries. Estimate the accuracy and precision of the age readings before and after the intercalibration. Take into account differences between areas and methods. Training of new horse mackerel readers

Relationship between casting modulus and grain size in cast A356 aluminium alloys

Microstructure of Al-Si alloy castings depends most generally on melt preparation and on the cooling rate imposed by the thermal modulus of the component. In the case of Al-Si alloys, emphasis is put during melt preparation on refinement of pro-eutectic (Al) grains and on modification of the Al-Si eutectic. Thermal analysis has been used since long to check melt preparation before casting, i.e. by analysis of the cooling curve during solidification of a sample cast in an instrumented cup. The conclusions drawn from such analysis are however valid for the particular cooling conditions of the cups. It thus appeared of interest to investigate how these conclusions could extrapolate to predict microstructure in complicated cast parts showing local changes in the solidification conditions. For that purpose, thermal analysis cups and instrumented sand and die castings with different thermal moduli and thus cooling rates have been made, and the whole set of cooling curves thus recorded has been analysed. A statistical analysis of the characteristic features of the cooling curves related to grain refinement in sand and die castings allowed determining the most significant parameters and expressing the cube of grain size as a polynomial of these parameters. After introduction of a further parameter quantifying melt refining an excellent correlation, with a R2 factor of 0.99 was obtained

La gestión integral del territorio rural en la localidad de Ciudad Bolívar de Bogotá

Para contribuir a la solución de la problemática social y agroambiental, se formuló y ejecutó el proyecto ¨Asistencia agroambiental rural en la localidad de Ciudad Bolívar, articulada a la generación de proyectos temáticos integrales (PTI)¨, el cual articuló iniciativas de la comunidad aprobadas por la Alcaldía local con propuestas concertadas, fomuladas y desarrolladas participativamente (PTI), por diferentes grupos de gestión de productores de las nueve veredas de la localidad

Scientific Advice on the estimation of surplus for Sustainable Fisheries Partnership Agreements.

Scientific advice on the concept of surplus, as defined by the UNCLOS, was provided for three types of Sustainable Fisheries Partnership Agreements (SFPAs): i) Mixed SFPAs in West Africa, ii) Tuna SFPAs and iii) SFPA with Greenland. For Mixed SFPAs in West Africa, methods for surplus computation were defined, including alternatives for cases of data limited stocks. These methods may use as input five parameters that could be obtained from those recent stocks assessments that are representative of the current stock status. Surplus estimates would need to be regularly updated (ideally, yearly), according to every new stock assessments and following the enforcement of a management plan (or, by default, according to a transition scheme towards reaching Fmsy in 2020). In the case of West African transboundary stocks, a theoretical share of the surplus could be calculated using a standard rule based on historical catches within EEZs. The Surplus concept is not applicable for Tuna SFPAs, due to the high migratory character of tuna or tuna-like species, the fact that these stocks are mostly found in areas beyond national jurisdictions, the lack of direct estimates of local abundance and impossibility to calculate the capacity of the coastal States. For the SFPA with Greenland, Surplus is considered as any TAC allocated to Greenland and not utilised by this coastal State

pSESYNTH project: Community mobilization for a multi-disciplinary paleo database of the Global South

How to enhance paleoscientific research, collaboration and application in the Global South? The INQUA-funded multi-year pSESYNTH project envisions the first multi-disciplinary Holocene paleo database through a collaborative vision for past human-environmental systems in the Global South, and their future sustainability

Nonlinear control with integral sliding properties for circular aerial robot trajectory tracking: Real‐time validation

International audienc

A Fully-Actuated Quadcopter Representation using Quaternions

Recent advances in practical fields like robotics and the miniaturization of many sensors and actuators have turned autonomous vehicles into a reality. These systems come in many shapes and forms depending on the medium and their design, but can be classified in one of two categories according to their mechanical configuration and number of actuators: fully actuated and under actuated vehicles, the second group still poses many challenges for the automatic control and robotics communities. This work introduces an easy methodology, based on quaternions, for designing controllers for a class of under-actuated systems, such as multicopter vehicles. The methodology starts from a fully actuated representation of the system and adapts it to be implemented in under actuated systems. In addition, it allows the easy development of controllers without take on care the coupled dynamics of the system. The proposed approach is based on Lyapunov's stability theory and is proven for certain criteria of the system's dynamics. The quadcopter configuration is used to validate the proposed methodology in simulations and in experimental tests.</p

Dual Quaternion Modeling and Control of a Quad-rotor Aerial Manipulator

International audienc