Vision System for a Forestry Navigation Machine.

This article presents the development of a vision system designed to enhance the autonomous navigation capabilities of robots in complex forest environments. Leveraging RGBD and thermic cameras, specifically the Intel RealSense 435i and FLIR ADK, the system integrates diverse visual sensors with advanced image processing algorithms. This integration enables robots to make real-time decisions, recognize obstacles, and dynamically adjust their trajectories during operation. The article focuses on the architectural aspects of the system, emphasizing the role of sensors and the formulation of algorithms crucial for ensuring safety during robot navigation in challenging forest terrains. Additionally, the article discusses the training of two datasets specifically tailored to forest environments, aiming to evaluate their impact on autonomous navigation. Tests conducted in real forest conditions affirm the effectiveness of the developed vision system. The results underscore the system's pivotal contribution to the autonomous navigation of robots in forest environments.

Unusual redox behaviour of the magnetite/hematite core-shell structures processed by the laser floating zone method.

Magnetite (Fe3O4) offers unique physical and chemical properties, being an important material for many industrial applications. Certain limitations on the application conditions are, however, imposed by the redox stability issue. Fine control of the iron oxidation states represents a challenge for materials engineering. The present work explores relevant redox processes in iron oxides, processed under highly non-equilibrium laser floating zone (LFZ) conditions under atmospheres with different oxygen activities. The as-grown fibres showed a structure composed of the Fe3O4 core and the Fe2O3 shell. This study uncovers unexpectedly lower hematite content and shell thickness for the fibres processed under more oxidizing conditions. Combined structural and microstructural studies, supported by the analysis of the existing literature data, strongly suggest that the redox processes during the LFZ process can be rather determined by kinetics of melt crystallization, nuclei formation and heat transfer than by the oxygen content in the gas phase. The proposed mechanisms are further confirmed by electrical and magnetic studies of the composite fibres.

Prospects and challenges of iron pyroelectrolysis in magnesium aluminosilicate melts near minimum liquidus temperature.

Although steel production by molten oxide electrolysis offers potential economic and environmental advantages over classic extractive metallurgy, its feasibility is far from being convincingly demonstrated, mainly due to inherent experimental difficulties exerted by harsh conditions and lack of knowledge regarding relevant mechanisms and physico-chemical processes in the melts. The present work was intended to demonstrate the concept of pyroelectrolysis at very high temperature near the minimum liquidus point of magnesium aluminosilicate, being conducted under electron-blocking conditions using yttria-stabilized zirconia cells, and to provide a new insight into electrochemistry behind this process. Significant current yields are possible for pyroelectrolysis performed in electron-blocking mode using a solid electrolyte membrane to separate the anode and the molten electrolyte. Parasitic electrochemical processes rise gradually as the concentration of iron oxide dissolved in the molten electrolytes is depleted, impairing faradaic efficiency. Reduction of silica to metallic silicon was identified as a significant contribution to those parasitic currents, among other plausible processes. Direct pyroelectrolysis without electron blocking was found much less plausible, due to major limitations on faradaic efficiency imposed by electronic leakage and insufficient ionic conductivity of the aluminosilicate melt. Ohmic losses may consume an excessive fraction of the applied voltage, thus failing to sustain the Nernst potential required for reduction to metallic iron. The results suggest the need for further optimization of the molten electrolyte composition to promote ionic conductivity and to suppress electronic transport contribution, possibly, by tuning the Al/Si ratio and altering the network-forming/modifying behaviour of the iron cations.

Processing strategies for smart electroconductive carbon nanotube-based bioceramic bone grafts.

Electroconductive bone grafts have been designed to control bone regeneration. Contrary to polymeric matrices, the translation of the carbon nanotube (CNT) electroconductivity into oxide ceramics is challenging due to the CNT oxidation during sintering. Sintering strategies involving reactive-bed pressureless sintering (RB + P) and hot-pressing (HP) were optimized towards prevention of CNT oxidation in glass/hydroxyapatite (HA) matrices. Both showed CNT retentions up to 80%, even at 1300 °C, yielding an increase of the electroconductivity in ten orders of magnitude relative to the matrix. The RB + P CNT compacts showed higher electroconductivity by ∼170% than the HP ones due to the lower damage to CNTs of the former route. Even so, highly reproducible conductivities with statistical variation below 5% and dense compacts up to 96% were only obtained by HP. The hot-pressed CNT compacts possessed no acute toxicity in a human osteoblastic cell line. A normal cellular adhesion and a marked orientation of the cell growth were observed over the CNT composites, with a proliferation/differentiation relationship favouring osteoblastic functional activity. These sintering strategies offer new insights into the sintering of electroconductive CNT containing bioactive ceramics with unlimited geometries for electrotherapy of the bone tissue.

Carbon nanotube-based bioceramic grafts for electrotherapy of bone.

Bone complexity demands the engineering of new scaffolding solutions for its reconstructive surgery. Emerging bone grafts should offer not only mechanical support but also functional properties to explore innovative bone therapies. Following this, ceramic bone grafts of Glass/hydroxyapatite (HA) reinforced with conductive carbon nanotubes (CNTs) - CNT/Glass/HA - were prepared for bone electrotherapy purposes. Computer-aided 3D microstructural reconstructions and TEM analysis of CNT/Glass/HA composites provided details on the CNT 3D network and further correlation to their functional properties. CNTs are arranged as sub-micrometric sized ropes bridging homogenously distributed ellipsoid-shaped agglomerates. This arrangement yielded composites with a percolation threshold of pc=1.5vol.%. At 4.4vol.% of CNTs, thermal and electrical conductivities of 1.5W·m(-1)·K(-1) and 55S·m(-1), respectively, were obtained, matching relevant requisites in electrical stimulation protocols. While the former avoids bone damaging from Joule's heat generation, the latter might allow the confinement of external electrical fields through the conductive material if used for in vivo electrical stimulation. Moreover, the electrically conductive bone grafts have better mechanical properties than those of the natural cortical bone. Overall, these highly conductive materials with controlled size CNT agglomerates might accelerate bone bonding and maximize the delivery of electrical stimulation during electrotherapy practices.

[Emotional involvement in the nursing team: reality or myth?]. / O envolvimento emocional para a equipe de enfermagem: realidade ou mito?

The present study aims to analyze what the members of the nursing team think about their emotional involvement with the patients during their relationship. Data were collected through the application of an instrument to members of the nursing team (registered nurse, nursing aides and attendants). The analysis was done, at first, separately by functional categories and after that, as a whole. We concluded that, there is in nursing a policy of no involvement with the patients and that the registered nurse is the one that most verbalizes it. One of the negative factors of the involvement with the patient is the psychological suffering of the nursing team members. This leads us to identify the no involvement behavior as a collective defence mechanism against suffering.

[A difficult relationship with cancer: the emotions of oncologic nurses]. / A difícil convivência com o câncer: um estudo das emoções na enfermagem oncológica.

The present study represents an attempt to verify which emotions are present in nursing activities with cancer patients and how nurses deal with them. In order to reach this goal, a quantitative approach was used in order to allow a comprehension of the population studied and their work conditions. After that, field observations and structured and semiestructured interviews were carried out so as to understand how emotion was experienced and dealt with. Thematic analysis of the nurses discourse was conducted in order to identify the core of the emotional issues and to elaborate the Maps of Association of ideas. The main themes were: the disease, the patient, the team and the health instituition, the emotions that emerged and ways of coping. Data analysis allowed to identfy which emotions are present in every day situations of nursing care, the ways of coping that are used with difficult situation and the mediation of the institutional culture in the control of emotional expressions.

[Effect of propranolol and metoprolol on cardiorespiratory and metabolic response to exercise]. / Efeito do propranolol e metoprolol nas respostas cárdio-respiratórias e metabólicas ao exercício.

PURPOSE: To study the effects of intravenous propranolol and metoprolol on cardiorespiratory and metabolic responses to exercise. METHODS: Two groups of anaesthetized dogs (sodium pentobarbital, 33 mg/kg) were studied at rest and moderate exercise (induced by electrical stimulation) before and after metoprolol (0.4 mg/kg, n = 7) or propranolol (0.2 mg/kg, n = 10). Haemodynamic, metabolic and respiratory variables were measured. RESULTS: There was a decrease in heart rate both at rest and during exercise after metoprolol and propranolol administration. The cardiac output, stroke volume and peripheral vascular resistance presented decreased responses to exercise after both drugs. O2 consumption and CO2 production were not altered significantly at rest but increased in a lesser degree during exercise. Propranolol administration reduced ventilation during rest and exercise, although the ventilatory response to exercise remained the same. Metoprolol administration did not affect ventilation at rest but reduced the ventilatory response to exercise leading to an increase of the PaCO2. CONCLUSION: Propranolol and metoprolol effects on cardiovascular and metabolic variables measured at rest and during exercise were the same. The ventilatory effect with metoprolol administration was different from the observed with propranolol.

Microbiologic study on stethoscopic eartips

Due to the inadequate use of stethoscopic eartips and the possibility of they being a source of infection of the ear, a microbiologic study has been carried out on 34 stethoscopes. The material from the eartips was cultured, one eartip being "contaminated", and the other disinfected previously with 70 per cent aqueous alcohol. Microorganisms developed in 100 per cent of the contaminated eartips and in 64.71 per cent of the clean ones. Howver ther was no statistically significant difference between the two groups, showing that 70 per cent aqueous alcohol is not an efficient disinfectant