48 results match your criteria: "Centre for Mechanical Technology and Automation TEMA[Affiliation]"

Hybrid Triboelectric-Electromagnetic Nanogenerators for Mechanical Energy Harvesting: A Review.

Nanomicro Lett

September 2021

Department of Mechanical Engineering, Centre for Mechanical Technology and Automation (TEMA), University of Aveiro, 3810-193, Aveiro, Portugal.

Motion-driven electromagnetic-triboelectric energy generators (E-TENGs) hold a great potential to provide higher voltages, higher currents and wider operating bandwidths than both electromagnetic and triboelectric generators standing alone. Therefore, they are promising solutions to autonomously supply a broad range of highly sophisticated devices. This paper provides a thorough review focused on major recent breakthroughs in the area of electromagnetic-triboelectric vibrational energy harvesting.

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Comparative Gravimetric Studies on Carbon Steel Corrosion in Selected Fruit Juices and Acidic Chloride Media (HCl) at Different pH.

Materials (Basel)

August 2021

Centre for Mechanical Technology and Automation (TEMA), Department of Mechanical Engineering, Campus Universitário de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal.

Food contamination due to metal corrosion and the consequent leakage of metals into foods is a problem. Understanding the mechanism(s) of metal corrosion in food media is vital to evaluating, mitigating, and predicting contamination levels. Fruit juices have been employed as model corrosive media to study the corrosion behaviour of metallic material in food media.

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How safe are the new green energy resources for marine wildlife? The case of lithium.

Environ Pollut

December 2020

Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal; LAQV-REQUIMTE - Associated Laboratory for Green Chemistry, University of Aveiro, Aveiro, Portugal.

Considering the increasing use of Lithium (Li) and the necessity to fulfil this demand, labile Li occurrence in the environment will be enhanced. Thus, additional research is needed regarding the presence of this element in marine environment and its potential toxic impacts towards inhabiting wildlife. The aim of the present study was to evaluate Li toxicity based on the exposure of Mytilus galloprovincialis to this metal, assessing the biochemical changes related with mussels' metabolism, oxidative stress and neurotoxicity.

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On-surface synthesis is emerging as a highly rational bottom-up methodology for the synthesis of molecular structures that are unattainable or complex to obtain by wet chemistry. Here, oligomers of meta-polyaniline, a known ferromagnetic polymer, were synthesized from para-aminophenol building-blocks via an unexpected and highly specific on-surface formal 1,4 Michael-type addition at the meta position, driven by the reduction of the aminophenol molecule. We rationalize this dehydrogenation and coupling reaction mechanism with a combination of in situ scanning tunneling and non-contact atomic force microscopies, high-resolution synchrotron-based X-ray photoemission spectroscopy and first-principles calculations.

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Natural and Eco-Friendly Materials for Triboelectric Energy Harvesting.

Nanomicro Lett

January 2020

Department of Physics and CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193, Aveiro, Portugal.

Triboelectric nanogenerators (TENGs) are promising electric energy harvesting devices as they can produce renewable clean energy using mechanical excitations from the environment. Several designs of triboelectric energy harvesters relying on biocompatible and eco-friendly natural materials have been introduced in recent years. Their ability to provide customizable self-powering for a wide range of applications, including biomedical devices, pressure and chemical sensors, and battery charging appliances, has been demonstrated.

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Conductive natural-based separators for application in polymer electrolyte fuel cells (PEFCs) were fabricated by combining a bacterial polysaccharide, i.e. bacterial cellulose (BC), and an algae sulphated polysaccharide, i.

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Effect of Solution Conditions on the Properties of Sol-Gel Derived Potassium Sodium Niobate Thin Films on Platinized Sapphire Substrates.

Nanomaterials (Basel)

November 2019

Department of Materials and Ceramic Engineering, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal.

If piezoelectric micro-devices based on KNaNbO (KNN) thin films are to achieve commercialization, it is critical to optimize the films' performance using low-cost scalable processing conditions. Here, sol-gel derived KNN thin films are deposited using 0.2 and 0.

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Recent studies highlight the ability of inductive architectures to deliver therapeutic magnetic stimuli to target tissues and to be embedded into small-scale intracorporeal medical devices. However, to date, current micro-scale biomagnetic devices require very high electric current excitations (usually exceeding 1 A) to ensure the delivery of efficient magnetic flux densities. This is a critical problem as advanced implantable devices demand self-powering, stand-alone and long-term operation.

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Integrating road traffic externalities through a sustainability indicator.

Sci Total Environ

November 2019

Department of Mechanical Engineering, Centre for Mechanical Technology and Automation (TEMA), University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.

Road traffic poses negative externalities on society and represents a key challenge in sustainable transportation. However, the existing literature about the assessment of traffic externalities drawn on a common measure is scarce. This paper develops a sustainability indicator that integrates traffic-related externalities as means of traffic congestion, noise, greenhouse gases (GHG) and nitrogen oxides emissions, health impacts and road crash related costs, and adjusted to local contexts of vulnerability.

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Interaction between motor vehicles and bicycles at two-lane roundabouts: a driving volatility-based analysis.

Int J Inj Contr Saf Promot

September 2019

a Department of Mechanical Engineering/Centre for Mechanical Technology and Automation (TEMA), University of Aveiro, Aveiro , Portugal.

Drivers' instantaneous decisions regarding speed and acceleration/deceleration, as well as the time rate of acceleration change (jerk) can result in a volatility driving behaviour with significant impact on cyclist safety. The contribution of this article is the assessment of driving volatility in motor vehicle (MV)-bicycle interactions at two-lane roundabouts. Traffic flow and bicycle GPS data were collected from two two-lane roundabouts.

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Toxicity evaluation of carboxylated carbon nanotubes to the reef-forming tubeworm Ficopomatus enigmaticus (Fauvel, 1923).

Mar Environ Res

January 2019

Interuniversitary Consortium of Marine Biology of Leghorn "G. Bacci", 57128, Livorno, Italy; Department of Veterinary Sciences, University of Pisa, San Piero a Grado, Pisa, 56122, Italy. Electronic address:

In recent years, oxidative stress has been recognized as one of the most common effects of nanoparticles in different organisms. Ficopomatus enigmaticus (Fauvel, 1923), a member of a large family of serpulidae polychates, is an important encrusting organism in a diverse set of marine habitats, from harbours to coral reefs. This species has been previously studied for ecotoxicological purposes, despite the lack of reported studies on this species biochemical response after exposure to different pollutants.

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While high-quality defect-free epitaxial graphene can be efficiently grown on metal substrates, strong interaction with the supporting metal quenches its outstanding properties. Thus, protocols to transfer graphene to insulating substrates are obligatory, and these often severely impair graphene properties by the introduction of structural or chemical defects. Here we describe a simple and easily scalable general methodology to structurally and electronically decouple epitaxial graphene from Pt(111) and Ir(111) metal surfaces.

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The present paper shows an experimental study on additive manufacturing for obtaining samples of polylactic acid (PLA). The process used for manufacturing these samples was fused deposition modeling (FDM). Little attention to the surface quality obtained in additive manufacturing processes has been paid by the research community.

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The supercritical carbon dioxide (scCO ) synthesis of non-reduced graphene oxide (GO) aerogels from dispersions of GO in ethanol is here reported as a low-cost, efficient, and environmentally friendly process. The preparation is carried out under the mild conditions of 333 K and 20 MPa. The high aspect ratio of the used GO sheets (ca.

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On-surface synthesis is an emerging approach to obtain, in a single step, precisely defined chemical species that cannot be obtained by other synthetic routes. The control of the electronic structure of organic/metal interfaces is crucial for defining the performance of many optoelectronic devices. A facile on-surface chemistry route has now been used to synthesize the strong electron-acceptor organic molecule quinoneazine directly on a Cu(110) surface, via thermally activated covalent coupling of para-aminophenol precursors.

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Exploring the Thermoelectric Performance of BaGdNiO Haldane Gap Materials.

Inorg Chem

February 2017

Centre for Mechanical Technology and Automation (TEMA), Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal.

Article Synopsis
  • One-dimensional Haldane gap materials, like rare earth barium chain nickelates, exhibit strong spin antiferromagnetic properties and unique structures that make them interesting for thermoelectric applications.
  • The material CaBaGdNiO shows impressive Seebeck coefficients of 140-280 μV K at high temperatures, maintained even with significant acceptor-substitution levels due to low dimensionality and electronic correlations.
  • Despite low thermal conductivities of around 1.5 W m K, ideal for thermoelectrics, the electrical conductivity of these materials is still insufficient, highlighting the need to improve electronic band structures and microstructural features to boost charge carrier mobility.
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Dehydrogenation Properties of Magnesium Hydride Loaded with Fe, Fe-C, and Fe-Mg Additives.

Chemphyschem

February 2017

Nanoengineering Research Group, Centre for Mechanical Technology and Automation (TEMA), Department of Mechanical Engineering, University of Aveiro, 3810-193, Aveiro, Portugal.

This study highlights that Fe additives offer better catalytic properties than carbon, Fe-C (iron carbide/carbon composites), and Fe-Mg (Mg FeH ) additives for the low-temperature dehydrogenation of magnesium hydride. The in situ X-ray diffraction measurements prove the formation of a Mg FeH phase in iron additive loaded MgH . Nonetheless, differential scanning calorimetry data suggest that this Mg FeH phase does not have any influence on dehydrogenation properties of MgH .

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Percutaneous vertebroplasty: a new animal model.

Spine J

October 2016

Departamento de Medicina Veterinária (DMV), Escola de Ciências e Tecnologia (ECT), Apartado 94, 7002-554 Évora, Portugal; Complexo de Laboratórios Tecnológicos (CICECO), Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.

Background Context: Percutaneous vertebroplasty (PVP) is a minimally invasive surgical procedure and is frequently performed in humans who need surgical treatment of vertebral fractures. PVP involves cement injection into the vertebral body, thereby providing rapid and significant pain relief.

Purpose: The testing of novel biomaterials depends on suitable animal models.

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Hybrid conjugates of graphene with metallic/semiconducting nanostructures can improve the sensitivity of electrochemical sensors due to their combination of well-balanced electrical/electrocatalytic properties and superior surface-to-volume ratio. In this study, the synthesis and physical characterization of a hybrid conjugate of reduced graphene oxide and nickel nanoparticles (rGO-Ni NPs) is presented. The conjugate was further deposited onto a glassy carbon electrode as a nanocomposite film of chitosan and glucose oxidase.

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The present study aims to understand the catalysis of the MgH2 -Nb2 O5 hydrogen storage system. To clarify the chemical interaction between MgH2 and Nb2 O5 , the mechanochemical reaction products of a composite mixture of MgH2 +0.167 Nb2 O5 was monitored at different time intervals (2, 5, 15, 30, and 45 min, as well as 1, 2, 5, 10, 15, 20, 25, and 30 h).

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From conventional sensors to fibre optic sensors for strain and force measurements in biomechanics applications: a review.

J Biomech

April 2014

Centre for Mechanical Technology and Automation (TEMA), Department of Mechanical Engineering, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.

Article Synopsis
  • - In vivo measurement in biomechanics seeks to collect data under physiological conditions in both animals and humans, aiming to create a database that enhances analytical models for understanding human biomechanics.
  • - The use of fibre optic sensors has evolved from traditional strain gages, demonstrating advantages such as being smaller, minimally invasive, and highly accurate, which makes them suitable for a variety of biomedical applications.
  • - This review article summarizes the progress of experimental techniques in biomechanics, focusing on the significant contributions of fibre optic sensors to in vivo measurements and their implications for clinical applications and rehabilitation.
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Enhanced thermal conductivity and viscosity of nanodiamond-nickel nanocomposite nanofluids.

Sci Rep

February 2014

Centre for Mechanical Technology and Automation (TEMA), Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal.

We report a new type of magnetic nanofluids, which is based on a hybrid composite of nanodiamond and nickel (ND-Ni) nanoparticles. We prepared the nanoparticles by an in-situ method involving the dispersion of caboxylated nanodiamond (c-ND) nanoparticles in ethylene glycol (EG) followed by mixing of nickel chloride and, at the reaction temperature of 140°C, the use of sodium borohydrate as the reducing agent to form the ND-Ni nanoparticles. We performed their detailed surface and magnetic characterization by X-ray diffraction, micro-Raman, high-resolution transmission electron microscopy, and vibrating sample magnetometer.

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Assessment of potential improvements on regional air quality modelling related with implementation of a detailed methodology for traffic emission estimation.

Sci Total Environ

February 2014

University of Aveiro, Centre for Environmental and Marine Studies (CESAM), Department of Environment and Planning, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.

The accuracy and precision of air quality models are usually associated with the emission inventories. Thus, in order to assess if there are any improvements on air quality regional simulations using detailed methodology of road traffic emission estimation, a regional air quality modelling system was applied. For this purpose, a combination of top-down and bottom-up approaches was used to build an emission inventory.

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