Camouflage of the seahorse Hippocampus reidi with plastic debris : an unusual type of protective resemblance

Camouflage is one of the strategies of reef fishes, in which they mimic other species or use the background to match the combination of their colors and textures (Randall 2005). Seahorses of the genus Hippocampus in a pristine habitat generally use saturated colors to camouflage their colorful background using matching or confusing objects as a deceiving mode (Stevens & Merilaita 2011). The present record is the first description of camouflage by the sea horse Hippocampus reidi Ginsburg, 1933 with plastic debris in mangroves from NE Brazil: Formoso River, Tamandaré, Pernambuco State (8°41′01.51″S, 35°06′25.92″ W). […]

A Methodology to Design FPGA-based PID Controllers

This paper presents a methodology to implement PID (Proportional, Integral, Derivative) controllers in FPGAs (Field-Programmable Gate Arrays) using fixed-point numerical representation. The Matlab/Simulink environment is used for modeling, simulation and evaluation the performance provided by different fixed-point representations using a given control process. A static bit-width analyzer is used to give a specialized fixed-point representation for each operand/operator in the controller system. After bit-width analysis, a VHDL represen-tation of the system is generated. Results show that the proposed methodology leads to shorten design cycles achieving important resource savings by employing specialized fixed-point repre-sentations

Processing of carbon reinforced thermoplastic pre-impregnated materials

The aim of this work is to produce and optimize the processing of carbon fibres thermoplastic matrix pre-impregnated materials (towpregs and PCT´s). Pultrusion and heated compression moulding were the selected manufacturing methods for processing all carbon fibres thermoplastic matrix pre-impregnated materials into composite parts. The optimization of those processes was made by studying the influence of the most relevant processing parameters in the final properties of the produced carbon fibres thermoplastic matrix pre-impregnated materials and composites. The method of Taguchi / DOE (Design of Experiments) was used to achieve this aim as it allowed making more rational choices of processing windows. The composite relevant mechanical properties were determined and studied. The final composites were also submitted to SEM microscopy analysis.info:eu-repo/semantics/publishedVersio

On the stability of elastic-plastic systems with hardening

This paper discusses the stability of quasi-static paths for a continuous elastic-plastic system with hardening in a one-dimensional (bar) domain. Mathematical formulations, as well as existence and uniqueness results for dynamic and quasi-static problems involving elastic-plastic systems with linear kinematic hardening are recalled in the paper. The concept of stability of quasi-static paths used here is essentially a continuity property of the system dynamic solutions relatively to the quasi-static ones, when (as in Lyapunov stability) the size of initial perturbations is decreased and the rate of application of the forces (which plays the role of the small parameter in singular perturbation problems) is also decreased to zero. The stability of the quasi-static paths of these elastic-plastic systems is the main result proved in the paper

Development of design software for plain masonry buildings

Paper 144As result of a benchmarking process on foreign computer codes for design of masonry buildings, the guidelines for the development of a Portuguese design software for plain masonry buildings are presented. The related software was inspired on Italian methods, particularly the RAN, and allows to perform a global response analysis of buildings, based on the assumption of a cumulative response of storeys and walls. Besides the assumptions of behaviour and equilibrium, modelling of stiffness and collapse mechanisms, the main features of the formulation adopted are presented. As a form of validation a case study is presented.(undefined