| 1. |
- Bender, Anke, et al.
(författare)
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Imaging-sonar observations of salmonid interactions with a vertical axis instream turbine
- 2023
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Ingår i: Rivers Research and Applications. - : John Wiley & Sons. - 1535-1459 .- 1535-1467.
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Tidskriftsartikel (refereegranskat)abstract
- Anthropogenic activities and their influences on aquatic systems is an important topic, especially considering the growing interest in using the earth's resources in a sustainable way. One of those anthropogenic activities is the introduction of renewable technologies into the aquatic environment such as instream turbines. Environmental studies around those technologies are often still ongoing due to their novelty. During the spring of 2018, juvenile individuals of two salmonid species, Atlantic salmon and brown trout were released upstream a vertical axis instream turbine in the river Dal (Dalälven) in eastern Sweden. The aim of this study was to investigate the swimming behavior of the salmonids around a small-scale prototype vertical axis instream turbine. The swimming pattern and the possible response of avoiding the vertical axis instream turbine were documented with a multi beam sonar. A control area, next to the turbine, was used as reference. No consistent results were shown for trout as they were passing the control area with a statistically high variation, and specimens were rarely observed in proximity of the turbine, neither if the turbine was operating nor at stand still. Salmon clearly avoided the operating turbine, but did not avoid the turbine when it was at stand still, and was often observed swimming straight through the turbine area. These findings indicate that operating this type of instream turbine in a river affects the swimming behavior of Atlantic salmon but is unlikely to affect its migration paths. For brown trout, the statistical results are inconclusive, although data indicate a response of avoiding the turbine. The species are in little risk to suffer physical harm as no fish entered the rotating turbine, despite very turbid water conditions.
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| 2. |
- Bender, Anke, et al.
(författare)
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A Review of Methods and Models for Environmental Monitoring of Marine Renewable Energy
- 2017
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Ingår i: Proceedings of the 12th European Wave and Tidal Energy Conference. - : EWTEC.
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Konferensbidrag (refereegranskat)abstract
- A continued expansion of the marine renewable energy sector will result in an increased demand in monitoring the natural marine environment. This may be due to a basic scientific interest but is foremost linked to the requirement of pre- and post-construction studies in relation to environmental impact assessments and consenting processes for marine renewable energy projects. With focus on wave and tidal power, but without attempting to provide a comprehensive list, we review methods, technologies and other scientific tools used for monitoring and predicting possible impacts from marine energy installations, on both population and behavioural levels. This includes traditional methods such as fishing gear, like nets and cages, modern technologies such as platforms with multi parameter equipment and the use of deterministic models. This paper is intended to serve as an overview for technology developers as well as authorities, regulators and decision makers with interests in general techniques, and naturally for scientists and consultants commonly being executors of studies and monitoring programs. By giving relevant and up to date references this paper may also be useful for finding more detailed information on study methods and variants. Finally, we give recommendations on where development of technologies is needed in order to face future requirements.
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| 3. |
- Costa, Joao, et al.
(författare)
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The burden of atherosclerosis in Portugal
- 2021
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Ingår i: European Heart Journal - Quality of Care and Clinical Outcomes. - : Oxford University Press. - 2058-5225 .- 2058-1742. ; 7:2, s. 154-162
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Tidskriftsartikel (refereegranskat)abstract
- Aims This article sought to estimate the burden of disease attributable to atherosclerosis in mainland Portugal in 2016.Methods and results The burden of atherosclerosis was measured in disability-adjusted life years following the latest 2010 Global Burden of Disease (GBD) methodology. Disability-adjusted life years were estimated as the sum of years of life lost (YLL) with years lived with disability (YLD). The following clinical manifestations of atherosclerosis were included: ischaemic heart disease (IHD) (including acute myocardial infarction, stable angina, and ischaemic heart failure), ischaemic cerebrovascular disease (ICVD), and peripheral arterial disease (PAD). Years of life lost were estimated based on all-cause mortality data for the Portuguese population and mortality due to IHD, ICVD, and PAD for the year 2016 sourced from national statistics. Standard life expectancy was sourced from the GBD study. Years lived with disability corresponded to the product of the number of prevalent cases by an average disability weight for all possible combinations of disease. Prevalence data for the different clinical manifestations of atherosclerosis were sourced from epidemiological studies. Disability weights were sourced from the published literature. In 2016, 15123 deaths were attributable to atherosclerosis, which corresponded to 14.3% of overall mortality in mainland Portugal. Disability-adjusted life years totalled 260943, 75% due to premature death (196438 YLL) and 25% due to disability (64505 YLD).Conclusion Atherosclerosis entails a high disease burden to society. A large part of this burden would be avoidable if evidence-based effective and cost-effective interventions targeting known risk factors, from prevention to treatment, were implemented.
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| 4. |
- Francisco, Francisco, 1985-
(författare)
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Adapting sonar systems for monitoring ocean energy technologies
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The global energy sector is under profound reforms aiming towards renewable energy sources, clean technologies and expansion of smart grids, all with the additional aim of providing affordable and dependable electricity for everyone. A reduction of carbon dioxide emissions is a priority on the global agenda, and to achieve that, cleaner energy technologies has to be more integrated into the energy mix. This thesis focus on a sustainable implementation of wave, tidal and offshore wind power, wherefore there is a need to investigate more about the prerequisites and consequences ocean energy can have on the marine environment. For that, reliable, cost effective and continuous environmental monitoring framework is necessary in order to support and safeguard ocean energy operations.The main objectives of the research presented in this thesis are to develop a multifunctional environmental monitoring platform based on sonar systems for ocean energy applications, by adapting high resolution multibeam, dual beam and split beam sonar systems and also underwater cameras; Propose data acquisition and processing protocols capable of decipher sonar data in order to provide continuous environmental monitoring and reporting; Conduct qualitative and quantitative observations of fish and marine mammals using the built monitoring platform; And investigate the feasibility of utilizing the Uppsala University wave energy converter technology to generate electricity worldwide. As a result, a multifunctional platform was designed, built and tested. This included the hardware, the data acquisition system, and a data analysis framework comprising new algorithms necessary to process the new acoustic data. The multibeam, dual beam, and split beam sonar systems and underwater cameras produced both qualitative and quantitative data of biomass, occurrence and behavior of fish and marine mammals in the vicinity of ocean energy devices. With this platform, it was also possible to conduct seabed and structural inspections within ocean energy devices, observe cavitating flows, etc. One of the most important results of this research was the possibility of extracting visual signatures of fish and marine mammals through acoustic images. This can be valuable for training algorithms for manual or automatic identification and classification of underwater targets through imaging sonar systems, a technique that can be widely used in the offshore activities. Regarding feasibility studies and wave power resource assessment, this study concluded that mild wave climates can provide enough energy to run reverse osmosis desalination systems as well as produce sufficient electricity to integrate into a national grid.In summary, this thesis concludes that the implementation of ocean energy can be facilitated by creating environmental monitoring, risk and resource assessment frameworks such as the presented research work that contribute to lowering the risks associated with subsea work and thereby costs of ocean energy projects.
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| 5. |
- Francisco, Francisco, 1985-, et al.
(författare)
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An alternative technique for ultra-high resolution bathymetry and seabed inspection for marine renewables
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Marine renewable energy technologies have a great potential in supplying clean electricity to millions of people across the globe, if technical and economic conditions are in right. So far, ocean energy projects are commonly started by SMEs or educational institutions with limited budgets. Therefore, any effort to reduce expenses is of great value. One of the areas involving substantial expenses are the inevitable seabed inspection prior to deployment of marine renewable energy device. Detailed seabed inspections can also reduce the risk of associated with deployment of structures on uneven seabed, especially marine renewable energy devices with gravity foundations. By reducing the costs and risks of such surveys prior and during the installation phases, the feasibility of marine renewable energy projects can be more favoured and competitive. In this perspective, this study proposes a cost and time effective technique for seabed surveys. The proposed technique involves the use of high precision and inexpensive sonar systems and underwater optical cameras integrated into a versatile and compact subsea monitoring platform. It also involves simple and practical data acquisition and processing protocols that do not requires hi expertise for operation. The results obtained showed that high resolution bathymetric maps and detailed seabed inspections imagery can be acquired. This study concludes that a simple and inexpensive subsea monitoring platform comprising a multibeam, dual beam and video cameras can be effective for high resolution seabed inspection and bathymetric measurements for marine energy applications.
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| 6. |
- Francisco, Francisco, 1985-, et al.
(författare)
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Detection of Visual Signatures of Marine Mammals and Fish within Marine Renewable Energy Farms Using Multibeam Imaging Sonar
- 2019
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Ingår i: Nutrients. - : MDPI. - 2072-6643. ; 7:2
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Tidskriftsartikel (refereegranskat)abstract
- Techniques for marine monitoring have evolved greatly over the past decades, making the acquisition of environment data safer, reliable and more efficient. On the other hand, the exploration of marine renewable energy introduced dissimilar ways of exploring the oceans and with that arises the need for new techniques for environmental data acquisition, processing and analysis. Marine energy is mostly harvested in murky and high energetic places where conventional data acquisition techniques are impractical. Modern sonar systems, operating at high frequencies, can acquire detailed images of the underwater environment. Variables such as occurrence, size, class and behaviour of a variety of aquatic species of fish, birds, mammals, coexisting within marine energy sites can be gathered using imaging sonar systems. Although sonar images can provide high level of details, still in most of the cases they are difficult to decipher. Therefore, to facilitate the classification of targets through sonar images, this study introduces a framework of extracting visual features of marine targets that would serve as unique signatures. The acoustic measure of visibility (AVM) is here introduced as an indirect technique of identification and classification of targets by comparing the observed size with a standard value. This information can be used to instruct manual and automatic algorithms for identification and classification of underwater targets using imaging sonar systems. Using image processing algorithms embedded in Proviwer4 and FIJI software, this study found that acoustic images can be effectively used to classify cod, harbour and grey seals, and orcas through their size, shape and swimming behaviour. Data showed that cod occurred as bright, 0.9 m long, ellipsoidal targets shoaling in groups of up to 50 individuals. Harbour seals occurred as bright torpedo-like fast moving target, whereas grey seals occurred as bulky-ellipsoidal targets with serpentine movement. Orca or larger marine mammals occurred with relatively low visibility on the acoustic images compared to their body size which measured between 4 m and 7 m. This framework provide a new window of performing qualitative and quantitative observations of underwater targets, and with further improvements, this method can be useful for environmental studies within marine renewable energy farms and for other purposes.
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| 7. |
- Francisco, Francisco, 1985-, et al.
(författare)
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Evaluation of Underwater Acoustic and Optical Imaging for Structural Inspections for Marine Renewables
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Ingår i: IEEE Journal of Oceanic Engineering.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Environmental monitoring and visual inspections are indispensable tasks in the marine renewable energy sector. Today, acoustic and electromagnetic instrumentation are used to observe the underwater environment. However, depending on the application, both electromagnetic and acoustic instruments have limitations mostly due to signal attenuation. For visual inspections, electromagnetic instruments e.g. optical cameras provide the best method of observation enabling an easy identification and classification of targets. However, electromagnetic radiation is more attenuated in water than sound, limiting the use of optical cameras to nearfield observations. In murky and turbid waters, acoustic imaging sonar systems can be used to observe underwater objects at much longer ranges up to 100 m away. Presumably, underwater optical images are mostly appropriate in clear waters or at nearfield, and acoustic images are suitable for murky and turbid waters. This study aimed to find the optimal ranges in which optical and acoustic images can be acquired in In Situ conditions. A multibeam imaging sonar and several different optical cameras were used to acquire underwater images of the surroundings of marine renewable energy devices. The results from observation showed that optical images were significantly affected by the decreasing of luminosity, increasing depth and water velocity. And acoustic images were mostly affected by water column stratification, bubbles and reverberation. In summary, optical cameras had superior performance for nearfield and high accuracy image acquisition, while imaging sonar provided superior performance at acquiring images at mid to long range.
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| 8. |
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| 9. |
- Francisco, Francisco Gemo Albino, 1985-, et al.
(författare)
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Sonar for environmental monitoring : Configuration of a multifunctional active acoustics platform applied for marine renewables
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Marine renewable energy is emerging as one of the fast-growing industry in the last decades, as modern society pushes for technologies that can convert energy contained from winds, waves, tides and stream flows. The implementation of renewable energy technologies impose high demands on both structural and environmental engineering, as the energy converters have to work under extreme conditions where parameters such as sea-bottom configuration, water transparency and depth, sea-states and prevailing winds are harsh. Constant monitoring of the marine environment is crucial in order to keep this sector reliable. Active acoustics is becoming a standard tool to collect multi-dimensional data from physical, geological and biological properties of the marine environment. The Div. of Electricity of Uppsala University have been developing an environmental monitoring platform based on sonar (Sound Navigation And Raging) systems. This platform aims to monitor the installation, operation and decommissioning of marine renewable energy converters. The focus will be given the observations of behaviours of marine animals in vicinity of energy converters but also structural inspection and monitoring of MRETs. This paper describes how this multifunctional environmental monitoring platform come to existence from the design to the deployment phase.
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| 10. |
- Francisco, Francisco, 1985-, et al.
(författare)
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Sonar for Environmental Monitoring : Understanding the Functionality of Active Acoustics as a Method for Monitoring Marine Renewable Energy Devices
- 2015
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Konferensbidrag (refereegranskat)abstract
- Active acoustics monitoring (AAM) systems can play an important role in the inspection and survey of the subsea environment around marine renewable energy devices, especially in murky and deep waters. Alternative methods comprising a multifunctional platform based on multibeam (MBS) and Dualbeam (DBS) sonar systems are being developed. The aim is to monitor the environmental impacts during installation, operation and maintenance of wave energy converters, marine current turbines, subsea substations and other offshore renewable energy technologies. At this initial phase, one of the specific objective is to understand the functionality of AAM systems. Field tests were done using the MBS and DBS systems. A platform is being tested at the Lysekil Wave Power Project test site and at the Söderfors Marine Current Project test site. Preliminary results show that the MBS produces better acoustic images when the platform is steady, and when in slow-moving waters such as in harbours and shallow rivers. At near field, the MBS is able to track targets < 20 cm such as fish swimming close to hard structures. The DBS can detect isolated targets at far field. Target dimensions estimated using the sonar match the real dimensions of the same´targets.
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