A Proposal for a Multi-Drive Heterogeneous Modular Pipe- Inspection Micro-Robot

This paper presents the architecture used to develop a micro-robot for narrow pipes inspection. Both the electromechanical design and the control scheme will be described. In pipe environments it is very useful to have a method to retrieve information of the state of the inside part of the pipes in order to detect damages, breaks and holes. Due to the di_erent types of pipes that exists, a modular approach with di_erent types of modules has been chosen in order to be able to adapt to the shape of the pipe and to chose the most appropriate gait. The micro-robot has been designed for narrow pipes, a _eld in which there are not many prototypes. The robot incorporates a camera module for visual inspection and several drive modules for locomotion and turn (helicoidal, inchworm, two degrees of freedom rotation). The control scheme is based on semi-distributed behavior control and is also described. A simulation environment is also presented for prototypes testing

Crystallization and melting of bacteria colonies and Brownian Bugs

Motivated by the existence of remarkably ordered cluster arrays of bacteria colonies growing in Petri dishes and related problems, we study the spontaneous emergence of clustering and patterns in a simple nonequilibrium system: the individual-based interacting Brownian bug model. We map this discrete model into a continuous Langevin equation which is the starting point for our extensive numerical analyses. For the two-dimensional case we report on the spontaneous generation of localized clusters of activity as well as a melting/freezing transition from a disordered or isotropic phase to an ordered one characterized by hexagonal patterns. We study in detail the analogies and differences with the well-established Kosterlitz-Thouless-Halperin-Nelson-Young theory of equilibrium melting, as well as with another competing theory. For that, we study translational and orientational correlations and perform a careful defect analysis. We find a non standard one-stage, defect-mediated, transition whose nature is only partially elucidated.Comment: 13 Figures. 14 pages. Submitted to Phys. Rev.

Comparison of microstructure and mechanical properties at different length scales of WC-Co hardmetals consolidated by binder jetting 3D printing and hip

Additive Manufacturing (AM) is rapidly growing as a revolutionary technique. It provides an interesting ability to produce complex geometries, a key feature for enhancing performance and widening application fields of hardmetal components, limited characteristic for traditional processing techniques. Within this context, it is necessary to study the mechanical integrity of samples produced by AM [AMed] where it is expected to find characteristics linked to the shaping route followed, and study if they will have influence on the final behaviour regarding the mechanical properties expect for a specimen process by a traditional manufacturing route. This work aims to study the final microstructure, mechanical properties and layer assemblage at different length scales for a 12%wtCo– WC grade hardmetals of medium grain size consolidated by binder jetting 3DP and subsequent SinterHIP. In addition, compare this results with the ones obtained from a 12%wtCo–WC specimens process by means of a traditional technique like Hot Isostatic Pressing (HIP) using the same raw material like in the AMed specimens. Hardness Vickers at macro- and microlength scale as well as scratch tests, using different loads and indenter tips, are conducted on both type of samples. The results are analysed and discussed in terms of oriented layer-like material assemblage effects on microstructural variability, mechanical response determined by intrinsic physical behaviour of the material and feedstock used

Brain Metabolism during Hallucination-Like Auditory Stimulation in Schizophrenia

Auditory verbal hallucinations (AVH) in schizophrenia are typically characterized by rich emotional content. Despite the prominent role of emotion in regulating normal perception, the neural interface between emotion-processing regions such as the amygdala and auditory regions involved in perception remains relatively unexplored in AVH. Here, we studied brain metabolism using FDG-PET in 9 remitted patients with schizophrenia that previously reported severe AVH during an acute psychotic episode and 8 matched healthy controls. Participants were scanned twice: (1) at rest and (2) during the perception of aversive auditory stimuli mimicking the content of AVH. Compared to controls, remitted patients showed an exaggerated response to the AVH-like stimuli in limbic and paralimbic regions, including the left amygdala. Furthermore, patients displayed abnormally strong connections between the amygdala and auditory regions of the cortex and thalamus, along with abnormally weak connections between the amygdala and medial prefrontal cortex. These results suggest that abnormal modulation of the auditory cortex by limbic-thalamic structures might be involved in the pathophysiology of AVH and may potentially account for the emotional features that characterize hallucinatory percepts in schizophrenia

Recovering long-term aerosol optical depth series (1976–2012) from an astronomical potassium-based resonance scattering spectrometer

A 37-year long-term series of monochromatic aerosol optical depth (AOD) has been recovered from solar irradiance measurements performed with the solar spectrometer Mark-I, deployed at Izaña mountain since 1976. The instrument operation is based on the method of resonant scattering, which affords wavelength absolute reference and stability (long-term stability and high precision) in comparison to other instruments based purely on interference filters. However, it has been specifically designed as a reference instrument for helioseismology, and its ability to determine AOD from transmitted and scattered monochromatic radiation at 769.9 nm inside a potassium vapour cell in the presence of a permanent magnetic field is evaluated in this paper. Particularly, the use of an exposed mirror arrangement to collect sunlight as well as the Sun–laboratory velocity dependence of the scattered component introduces some important inconveniences to overcome when we perform the instrument's calibration. We have solved this problem using a quasi-continuous Langley calibration technique and a refinement procedure to correct for calibration errors as well as for the fictitious diurnal cycle on AOD data. Our results showed similar calibration errors retrieved by means of this quasi-continuous Langley technique applied in different aerosol load events (from 0.04 to 0.3), provided aerosol concentration remains constant throughout the calibration interval.The AERONET sun photometers at Izaña have been calibrated within AERONET-Europe TNA supported by the European Community-Research Infrastructure Action under the FP7 “Capacities” specific programme for Integrating Activities, ACTRIS grant agreement no. 262254. The GAW-PFR network for AOD at WMO-GAW global observatories has been implemented by the World Optical Depth Research and Calibration Center (WORCC). Mark-I operation was supported by the Spanish National Plan of Research and Development under grant no. AYA2012–17803

Intrinsic hardness of constitutive phases in WC–Co composites:Nanoindentation testing, statistical analysis, WC crystal orientation effectsand flow stress for the constrained metallic binder

The intrinsic hardness of the constitutive phases in WC–Co composites is investigated by combining experimental and statistical analysis nanoindentation techniques. It is done on the basis of considering the cemented carbide material as effectively heterogeneous at the microstructure scale, i.e. consisting of three phases defined by either different chemical nature (carbides and binder) or distinct carbide crystal orientation (i.e. with surface normal perpendicular to either basal or prismatic planes). As main outcome, experimentally measured and statistically significant intrinsic hardness values for the defined phases (WC and constrained metallic binder) are analyzed and determined. Besides the evidence of crystal anisotropy for the WC phase, they permit to identify and account the expected strengthening of the plastic-constrained metallic binder, a critical input parameter for hardness and toughness modelling as well as for microstructural design optimization of ceramic composites reinforced by ductile metallic ligamentsPeer ReviewedPostprint (author's final draft

Competencia retórica. Una propuesta para interpretar las dificultades de comprensión

Este trabajo mide el impacto de la Competencia Retórica –la capacidad para operar con los mecanismos que proporcionan coherencia al texto- en la comprensión lectora. Concretamente, se considera la habilidad para operar con dos mecanismos textuales diferentes: las conectivas lógicas y los dispositivos anafóricos. Con ello se ofrece una interpretación comunicativa amplia de las dificultades de comprensión que experimentan muchos lectores: la dificultad para interpretar las intenciones e ideas de un emisor apoyándose en las señales que su mensaje encierra, señales que se hacen más complejas en el tránsito de lo oral a lo escrito, siendo pues aquí donde la competencia retórica cobra un papel mayor. Los resultados confirman la importancia de la competencia retórica en el proceso de comprensión y su peso específico frente a otras variables: conocimientos previos, reconocimiento de palabras y memoria de trabajo. Faltaría determinar la dirección de su relación con la comprensión.ABSTRACT: This work assesses the impact that Rhetoric Competence–the abilityto operatewith themechanismsthat provide coherence to a text–hason text comprehension. Specifically, we take into account the ability to operate with two different text mechanisms: logical connectives and anaphoric devices. This way, we try to provide a broad communicative interpretation to the comprehension problemsfelt by many readers: the difficulty tointerpret the purpose and ideasof anauthor or speaker fromthe signals used in his / her message, signals that become more complex when we shift fromoral to writtencommunication. In this last kind of communication, rhetoric competence comes to play a more important role. Results confirm the importance of rhetoric competence in the comprehension process and its specificweight in relation toother variables: previous knowledge,wordrecognition and working-mem o r y. The direction of the relation between rhetoric competence and comprehension is yet to be determined

Leitura conjunta: Limitações e possibilidades

Este artigo dedica-se a apresentar os resultados de um trabalho experimental e de um conjunto de estudos observacionais relacionados com o estudo da compreensão de textos. No trabalho experimental, os autores investigaram o impacto de um sistema de apoios/mediações, oferecido antes e durante a leitura, na compreensão de um texto, medida a diferentes níveis. Depois de analisado o seu principal resultado - a constatação de que, para serem úteis, as ajudas a dar aos leitores remetem para uma grande exigência e disponibilidade por parte do/a professor/a - os autores passam a comentar a questão das dificuldades sentidas pelos/as professores/ as para pôr em prática as propostas provenientes dos marcos teóricos vigentes sobre interacções professor/a - alunos e compreensão de textos