Oct 21

Validation of a method to quantify microfibres present in aquatic surface microlayers

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Joshua Birkenhead, Freya Radford, Jessica Stead, Prof Andy Cundy and Dr Malcom Hudson.

Published on 21 Oct 2020

Abstract

Many of the methods for microplastics quantification in the environment are criticised creating problems with data validity. Quantification of microplastics in the surface microlayer of aquatic environments using glass plate dipping holds promise as a simple field method, but its efficiency has yet to be validated. We tested a standard glass plate dipping method to assess recovery of four common polymer microfibres and two common natural fibres, under three different salinities (freshwater, brackish water, saltwater). Overall recovery rates were low (26.8 ± 1.54%) but higher recoveries were observed under saltwater treatments (36.5 ± 3.01%) than brackish water (24.5 ± 1.92%) or freshwater (19.3 ± 1.92%). The fibre types showed different recovery rates, with acrylic yielding significantly higher recovery rates (37.0 ± 2.71%) than other fibres across treatments. No clear relationship between the density of the fibres and the recovery efficiency was seen. We suggest that, where this method is used for monitoring microplastics, the results will typically underestimate the total amount present, but that recovery is sufficiently consistent to allow comparison of differences between sampling locations. When comparing data across river-estuarine or similar transects salinity should be monitored to account for salinity-induced differences in sampling recovery.

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Sep 30

A featureless approach to improve self-consistency in structured light bathymetry

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Research Article

Stanley, David, Bodenmann, Adrian, Massot Campos, Miguel and Thornton, Blair (2020)

2020 IEEE OES Autonomous Underwater Vehicle Symposium, Online, Canada. 30 Sep – 02 Oct 2020. 6 pp . (Submitted)

Submitted date: 11 September 2020
Venue – Dates: 2020 IEEE OES Autonomous Underwater Vehicle Symposium, Online, Canada, 2020-09-30 – 2020-10-02
Record type: Conference or Workshop Item (Paper)

Abstract

This paper describes a novel method for calibrating structured light setups using a featureless approach to quantify and improve self-consistency in bathymetric maps. The self-consistency and accuracy of seafloor reconstructions and information derived from them are limited by uncertainties in vehicle localisation, sensor models and their calibration. For high-resolution setups such as structured light, these uncertainties can be several orders of magnitude larger than the resolution of the maps generated. Although techniques such as simultaneous localisation and mapping and bundle adjustment can correct pose estimates and sensor calibrations to improve map self-consistency, both methods typically rely on finding and matching features in the data, which limits their application to structured light since a key advantage of this method is that it does not rely on seafloor features to be present in order to work. In this paper, we develop a fully featureless approach to improve self-consistency in structured light setups. Simulations are performed to validate the proposed method, and we analyse data that was collected using the Autosub6000 autonomous underwater vehicle equipped with the BioCam seafloor mapping instrument at a depth of approximately 1000m in the Darwin Mounds UK marine protected area. The results for independent parameter optimisation demonstrate that the fully featureless approach can converge towards optimal calibrations.

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Sep 25

Environment Agency’s bristles help fish in Isle of Wight rivers

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CDT-SIS graduate Dr Daniella Montali-Ashworth is now working with the Environment Agency and her Cylindrical Bristle Clusters have been installed on rivers on the Isle of Wight during the summer of 2020.

Articles in the local press from September 25, 2020.

https://www.iwradio.co.uk/news/isle-of-wight-news/fintastic-new-technology-helps-fish-in-isle-of-wight-rivers/

https://www.islandecho.co.uk/fish-given-a-helping-hand-thanks-to-environment-agency-clusters/

https://www.countypress.co.uk/news/18748472.environment-agencys-bristles-help-fish-isle-wight-rivers/ 

Read the rest of this entry »

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Sep 01

A mechanical approach to understanding the impact of the nematode Anguillicoloides crassus on the European eel swimbladder

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CDT SIS Students, Current Research, Publications

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Research Article

Each CDT SIS cohort undertake a group project with researchers from different disciplines working together to understand and research a complex real world problem sustainable engineering problems. Read the rest of this entry »

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Aug 30

A transferable method for estimating the economic impacts of track interventions: application to ground-borne noise reduction measures for whole sections of route

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Marcus Young, Georgios Rempelos, Evangelos Ntotsios, Dr Simon Blainey, Prof David Thompson and Prof Jonathan Preston

Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit

0954-4097

Scopus rating (2019): CiteScore 3.4 SJR 0.58 SNIP 1.296

10.1177/0954409720953730

 

Abstract

The environmental impacts of noise and vibration are becoming increasingly important in the assessment of new and upgraded railway routes. Vibration from railways propagates through the ground to nearby buildings where it may cause annoyance as feelable vibration or as re-radiated noise. To tackle the adverse effects of ground-borne noise a range of possible interventions are available, including softer rail pads, under-sleeper pads and under-ballast mats. The installation costs of such interventions are generally higher for the higher-performing track types. Additionally, there are potential effects on track maintenance costs which may be positive or negative, for example by reducing sleeper damage or increasing the need for ballast tamping. This study presents a socio-economic analysis of the effects of several interventions to reduce ground-borne noise. By selecting a whole route, the installation and whole-life costs are assessed using Network Rail’s Vehicle-Track Interaction Strategic Model (VTISM) and these are offset against benefits in terms of reduced social costs. Ground-borne noise is predicted at various distances from the alignment using the Modelling of Train Induced Vibration (MOTIV) model and the effect of track interventions is determined as insertion loss spectra. The re-radiated noise within a typical domestic building is then estimated using generic building transfer functions. Geographic Information System tools are used to estimate the population affected by ground-borne noise and their expected level of exposure. The methodology is illustrated using a case study route between Brighton and Portsmouth in the South of England.

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Aug 10

The Southampton System: a new universal standard approach for port-city classification

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Research Article

Toby Roberts , Ian Williams  & John Preston 

Published online for Taylor and Francis: 10 Aug 2020

Abstract

The most widely-used current system for classifying port-cities is limited to container ports, excluding other types of cargo and passengers. This limits the usefulness of research findings and policy recommendations.

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Jun 17

Analogies in contextualizing human response to airborne ultrasound and fish response to acoustic noise and deterrents

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Research Article

Proceedings of Meetings on Acoustics. 37, 010014 (2019); https://doi.org/10.1121/2.0001260
Journal of the Acoustical Society of America
 Timothy G. Leighton1, Helen A. L. Currie2, Amelia Holgate2, Craig N. Dolder1, Sian Lloyd Jones1, Paul R. White1, and Paul S. Kemp2
Published Online: 17 June 2020
ABSTRACT
In assessing the impact of sound on aquatic life, or its potential to guide fauna away from hazards, there is reliance on decades of human audiology, for example by adapting tests such as behavioral audiograms and Auditory Evoked Potentials.
However, now that human audiology has translated over decades from research laboratories to the high-street hearing-aid dispenser, we might forget the underlying challenges that human audiology overcame, and which face its aquatic analogue because it is still in its infancy.
A major challenge of researching effects of sound on fish comes from sparsity of data. One aspect of human audiology that shares this characteristic is the effect of Very High Frequency sound/ultrasound in air on humans. Their similarities will be discussed in terms of the difficulties associated with: lack of appreciation of the complexities of the sound field; lack of recognized calibrations and measurement procedures; reliance on the concept of a ‘typical’ subject based on an average; reliance on data from too few subjects; insufficient appreciation of group effects; reliance on a tacit assumption of an assumed mapping between threshold for hearing and threshold for behavioral/adverse effects; the tension between field and laboratory observations; and confusion caused by inexpert reporting.

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Jun 01

The influence of pier geometry and debris characteristics on the accumulation of woody debris at bridge piers

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The influence of pier geometry and debris characteristics on the accumulation of woody debris at bridge piers

Diego Panici & Dr Gustavo De Almeida, University of Southampton

First published: 01/06/2020,

Journal of Hydraulic Engineering, vol. 146, no. 6.

https://doi.org/10.1061/(ASCE)HY.1943-7900.0001757

Abstract

This paper analyses the influence of the geometry of bridge piers and the geometry of the supplied debris on the formation and growth of wood debris jams at bridge piers. A total of 162 laboratory experiments have been conducted. Experimental results showed that the maximum size of debris jams formed by the accumulation of cylindrical debris (i.e. wooden dowels) is smaller than that of jams formed by natural non-branched wood of irregular shape. In addition, experiments with branched debris resulted in jams that were significantly smaller and less stable than those with non-branched natural debris. Finally, comparison of experiments conducted with six different pier shapes indicate that the shape of a pier has negligible effects on the maximum size of a woody debris jam. The only exception to this observation was for square piers, which showed slightly larger debris jam sizes than the other types of piers tested.

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Jun 01

The influence of pier geometry and debris characteristics on the accumulation of woody debris at bridge piers

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Research Article

Panici, D. & De Almeida, G.,

Published on 1 Jun 2020,

In : Journal of Hydraulic Engineering. 146, 6, 31 p.

DOI 10.1061/(ASCE)HY.1943-7900.0001757

Abstract

This paper analyses the influence of the geometry of bridge piers and the geometry of the supplied debris on the formation and growth of wood debris jams at bridge piers. A total of 162 laboratory experiments have been conducted. Experimental results showed that the maximum size of debris jams formed by the accumulation of cylindrical debris (i.e. wooden dowels) is smaller than that of jams formed by natural non-branched wood of irregular shape. In addition, experiments with branched debris resulted in jams that were significantly smaller and less stable than those with non-branched natural debris. Finally, comparison of experiments conducted with six different pier shapes indicate that the shape of a pier has negligible effects on the maximum size of a woody debris jam. The only exception to this observation was for square piers, which showed slightly larger debris jam sizes than the other types of piers tested.

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