31 research outputs found

    Supported-Metal Oxide Nanoparticles-Potential Photocatalysts

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    Recently, nanosized metal oxides play an essential role in the photocatalytic system due to their ability to create charge carriers during the light irradiation. Metal oxide nanoparticles display excellent light absorption properties, outstanding charge transport characteristics, which are suitable in the photocatalytic system for the treatment of wastewater. Most of the photocatalysts found in the literature are in the form of powders. Only a few supported photocatalytic systems have been reported. The advantages of supported photocatalysts, such as that they produce a small pressure drop, have good mechanical stability and are easily separated from the reaction medium, make them superior to conventional powder photocatalysts. In this chapter, the definition of supported-metal oxide nanoparticles as the photocatalyst and their synthesis methodology are detailed discussed

    Experiments on the Ionospheric Models in GNSS

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    In GNSS, one of the main error sources of the Standard Positioning Service (SPS) is introduced by the ionosphere. Although this error can be cancelled by combining two signals at different frequencies, most of the single - frequency mass - market receivers do not benefit from this cancel l ation. For that reason, a set of parameter s is included in the navigation message in order to compute the ionospheric delay of any observation by the Klobuchar model. The Klobuchar model is a very simple model that is able to remove more than the 50% of the ionospheric delay. Recently, more accurate ionospheric models have been introduced such as Global Ionospheric Map (GIM) or the F ast P recise P oint P ositioning ( F PPP ) ionospheric model. In previous works, with data gathered in Europe, it was shown the advantage of the F PPP’s ionospheric model. In this work, we conduct experiments to compare the performance of different ionospheric modelling methods including: Klobuchar, GIM s and F PPP. Our preliminary results show how F PPP and GIM s lead to better positioning precisions compared to the Klobuchar model. However, since data is not wide enough to cover different ionospheric cond itions, more experiments will be carried out in our future work to validate the current result s .Peer ReviewedPostprint (published version

    Facile Template In-Situ Fabrication of ZnCo2O4 Nanoparticles with Highly Photocatalytic Activities under Visible-Light Irradiation

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    High specific surface area ZnCo2O4 nanoparticles were prepared via a sacrificial template accelerated hydrolysis by using nanoparticles of ZnO with highly polar properties as a template. The obtained ZnCo2O4 nanoparticles were characterized by the method of scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area measurements, Transmission electron microscopy (TEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The obtained nanoparticles were performed as a photocatalyst for the degradation of methylene blue in aqueous solution under visible irradiation. The photocatalytic degradation rate of methylene blue onto the synthesized ZnCo2O4 was higher than that of commercial ZnO and synthesized ZnO template. Copyright © 2019 BCREC Group. All rights reserved

    The BELS Pproject: an opportunity for setting collaboration links between Europe and South East Asia in the field of GNSS

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    In 2016 the European Global Navigation Satellite System (EGNSS) Galileo should start initial services that will make it available for practical use together with other existing Global Navigation Satellite Systems (GNSS). South East Asia (SEA), which is the Region in the world with the highest multi-GNSS coverage, but has not developed any of them, is the ideal place to promote EGNSS solutions and related technologies to facilitate business while supporting sustainable development. This paper describes the opportunities offered by the project BELS to companies, institutions, researchers from Europe and SEA working in the field of GNSS. The project is funded by the European GNSS Agency (GSA) under the European Union’s Research Framework Programme Horizon 2020.

    Local Government Law

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    Ionospheric scintillation causes rapid fluctuations of measurements from Global Navigation Satellite Systems (GNSSs), thus threatening space-based communication and geolocation services. The phenomenon is most intense in equatorial regions, around the equinoxes and in maximum solar cycle conditions. Currently, ionospheric scintillation monitoring receivers (ISMRs) measure scintillation with high-pass filter algorithms involving high sampling rates, e.g. 50 Hz, and highly stable clocks, e.g. an ultra-low-noise Oven-Controlled Crystal Oscillator. The present paper evolves phase scintillation indices implemented in conventional geodetic receivers with sampling rates of 1 Hz and rapidly fluctuating clocks. The method is capable to mitigate ISMR artefacts that contaminate the readings of the state-of-the-art phase scintillation index. Our results agree in more than 99.9% within¿±¿0.05 rad (2 mm) of the ISMRs, with a data set of 8 days which include periods of moderate and strong scintillation. The discrepancies are clearly identified, being associated with data gaps and to cycle-slips in the carrier-phase tracking of ISMR that occur simultaneously with ionospheric scintillation. The technique opens the door to use huge databases available from the International GNSS Service and other centres for scintillation studies. This involves GNSS measurements from hundreds of worldwide-distributed geodetic receivers over more than one Solar Cycle. This overcomes the current limitations of scintillation studies using ISMRs, as only a few tens of ISMRs are available and their data are provided just for short periods of time.Peer Reviewe

    Ionosphere Monitoring in South East Asia in the ERICA Study

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    The ERICA study aims to find out signatures of the interplay between the magnetosphere‐geomagnetic field and the ionosphere that degrade trans‐ionospheric signals such as those transmitted by GNSS satellites. The project activity focuses on the characterization of the ionospheric variability of the Equatorial Ionospheric Anomaly in the South East Asian region through the analysis of datasets collected with an ad hoc measurements campaign. The campaign has been conducted with ground‐based instruments located in the footprints of the Equatorial Ionospheric Anomaly and Equatorial Ionospheric Trough. This paper presents some of the relevant results achieved by the project, in terms of ionospheric climatology and weather assessment over the interested area. In particular, the paper describes the average condition of the Equatorial Ionospheric Anomaly recorded during the entire campaign and provides interesting insights on relevant scintillation events.Published273-2871A. Geomagnetismo e Paleomagnetismo2A. Fisica dell'alta atmosferaJCR Journa

    Towards Smart Homes Using Low Level Sensory Data

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    Ubiquitous Life Care (u-Life care) is receiving attention because it provides high quality and low cost care services. To provide spontaneous and robust healthcare services, knowledge of a patient’s real-time daily life activities is required. Context information with real-time daily life activities can help to provide better services and to improve healthcare delivery. The performance and accuracy of existing life care systems is not reliable, even with a limited number of services. This paper presents a Human Activity Recognition Engine (HARE) that monitors human health as well as activities using heterogeneous sensor technology and processes these activities intelligently on a Cloud platform for providing improved care at low cost. We focus on activity recognition using video-based, wearable sensor-based, and location-based activity recognition engines and then use intelligent processing to analyze the context of the activities performed. The experimental results of all the components showed good accuracy against existing techniques. The system is deployed on Cloud for Alzheimer’s disease patients (as a case study) with four activity recognition engines to identify low level activity from the raw data captured by sensors. These are then manipulated using ontology to infer higher level activities and make decisions about a patient’s activity using patient profile information and customized rules

    An Adaptive Bandwidth Notch Filter for GNSS Narrowband Interference Mitigation

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    The low level of received signals power makes Global Navigation Satellite Systems (GNSS) receivers vulnerable to many classes of disturbing signals. Among them, narrow band interference (NBI) might cause serious receiver performance degradation. Cancellation of NBI can be implemented by using notch filters (NF), which are controlled by two parameters: the notch frequency, which specifies the band center, and the notch bandwidth, which defines the spectrum area to be removed. The literature on the topic focuses on adapting the notch frequency, without estimating the filter bandwidth. This paper proposes a method able to determine both the notch parameters, optimizing the interference suppression. The performance analysis shows a good improvement by using the adaptive bandwidth notch filter

    Analysis of the Regional Ionosphere at Low Latitudes in Support of the Biomass ESA Mission

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    Biomass is a spaceborn polarimetric P-band (435 MHz) synthetic aperture radar (SAR) in a dawn-dusk low Earth orbit. Its principal objective is to measure biomass content and change in all the Earth’s forests. The ionosphere introduces Faraday rotation on every pulse emitted by low-frequency SAR and scintillations when the pulse traverses a region of plasma irregularities, consequently impacting the quality of the imaging. Some of these effects are due to Total Electron Content (TEC) and its gradients along the propagation path. Therefore, an accurate assessment of the ionospheric morphology and dynamics is necessary to properly understand the impact on image quality, especially in the equatorial and tropical regions. To this scope, we have conducted an in-depth investigation of the significant noise budget introduced by the two crests of the Equatorial Ionospheric Anomaly (EIA) over Brazil and South-East Asia. The work is characterized by a novel approach to conceive a SAR-oriented ionospheric assessment, aimed at detecting and identifying spatial and temporal TEC gradients, including scintillation effects and Traveling Ionospheric Disturbances, by means of Global Navigation Satellite Systems (GNSS) ground-based monitoring stations. The novelty of this approach resides in the customization of the information about the impact of the ionosphere on SAR imaging as derived by local dense networks of ground instruments operating during the passes of Biomass spacecraft. The results identify the EIA crests as the regions hosting the bulk of irregularities potentially causing degradation on SAR imaging. Interesting insights about the local characteristics of low-latitudes ionosphere are also highlighted
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