Scientific documents

Scientific documents

2017

eShark

by eShark Consortium

Topic: Shipcoating
Abstract Synopsis

Powered by EU-funding, a consortium consisting of the world’s leading marine experts and engineers are working together to create an innovative new fouling protection system for commercial seagoing vessels, and to accelerate its entry to market. This project is called eSHaRk (Eco-friendly Ship Hull film system with fouling release and fuel saving properties). The eSHaRk project aims to bring a greener and more efficient anti-fouling solution to the market. This innovative new technology not only maintains current fouling protection standards but is superior to existing solutions in terms of eco-friendliness, ease of application, durability and drag-reduction, all of which will lead to fuel savings and a reduction in greenhouse gas (GHG) emissions.

 

Plant surfaces: structures and functions for biomimetic innovations

by Barthlott, W., et al.

Topic: Biomimicry

Abstract Synopsis

An overview of plant surface structures and their evolution is presented. It combines surface chemistry and architecture with their functions and refers to possible biomimetic applications. Within some 3.5 billion years biological species evolved highly complex multifunctional surfaces for interacting with their environments: some 10 million living prototypes (i.e., estimated number of existing plants and animals) for engineers. The complexity of the hierarchical structures and their functionality in biological organisms surpasses all abiotic natural surfaces: even superhydrophobicity is restricted in nature to living organisms and was probably a key evolutionary step with the invasion of terrestrial habitats some 350–450 million years ago in plants and insects. Special attention should be paid to the fact that global environmental change implies a dramatic loss of species and with it the biological role models.

Maintenance of air layer and drag reduction on superhydrophobic surface. Ocean Engineering

by Du, P., et al.

Topic: Shipcoating

Abstract Synopsis

Hydrophobic surface for drag reduction on marine vehicles and structures has been proposed for many years. However, the drag reduction effect has been found to be unstable under high flow speed/pressure conditions because of the destruction of air-water interface. In this paper, an air layer was maintained experimentally by continuous air injection on hydrophobic surfaces. Good hydrophobicity was found to benefit the spread of air bubbles and the formation of a wide and flat air layer on solid surfaces. Based on this recognition, a method combining air injection and surface hydrophobicity adjustment was proposed to maintain the air layer.

Global assessment of shipping emissions in 2015 on a high spatial and temporal resolution

by Johansson, L., J.-P. Jalkanen, and J. Kukkonen

Topic: Emissions

Abstract Synopsis

Powered by EU-funding, a consortium consisting of the world’s leading marine experts and engineers are working together to create an innovative new fouling protection system for commercial seagoing vessels, and to accelerate its entry to market. This project is called eSHaRk (Eco-friendly Ship Hull film system with fouling release and fuel saving properties). The eSHaRk project aims to bring a greener and more efficient anti-fouling solution to the market. This innovative new technology not only maintains current fouling protection standards but is superior to existing solutions in terms of eco-friendliness, ease of application, durability and drag-reduction, all of which will lead to fuel savings and a reduction in greenhouse gas (GHG) emissions.

 

2016

PPG SIGMAGLIDE® 1290

by PPG

Topic: Biofouling / Shipcoating

Abstract Synopsis

Based on a 100% pure silicone binder system, the SIGMAGLIDE 1290 product utilizes a breakthrough dynamic surface regeneration technology to eliminate slime problems and dramatically increase fuel savings throughout service when compared to traditional fouling release products.

Superhydrophobic hierarchically structured surfaces in biology: evolution, structural principles and biomimetic applications

by Barthlott, W., M. Mail, and C. Neinhuis

Topic: Biomimicry

Abstract Synopsis

A comprehensive survey of the construction principles and occurrences of superhydrophobic surfaces in plants, animals and other organisms is provided and is based on our own scanning electron microscopic examinations of almost 20 000 different species and the existing literature. Properties such as self-cleaning (lotus effect), fluid drag reduction (Salvinia effect) and the introduction of new functions (air layers as sensory systems) are described and biomimetic applications are discussed: self-cleaning is established, drag reduction becomes increasingly important, and novel air-retaining grid technology is introduced. Surprisingly, no evidence for lasting superhydrophobicity in non-biological surfaces exists (except technical materials).

A comprehensive inventory of ship traffic exhaust emissions in the European sea areas in 2011

by Jalkanen, J.-P., L. Johansson, and J. Kukkonen

Topic: Emissions

Abstract Synopsis

Emissions originating from ship traffic in European sea areas were modelled using the Ship Traffic Emission Assessment Model (STEAM), which uses Automatic Identification System data to describe ship traffic activity. We have estimated the emissions from ship traffic in the whole of Europe in 2011. We report the emission totals, the seasonal variation, the geographical distribution of emissions, and their disaggregation between various ship types and flag states. The total ship emissions of CO2, NOx, SOx, CO, and PM2.5 in Europe for year 2011 were estimated to be 121, 3.0, 1.2, 0.2, and 0.2 million tons, respectively.

Effects of the air layer of an idealized superhydrophobic surface on the slip length and skin-friction drag

by Jung, T., H. Choi, and J. Kim

Topic: Shipcoating

Abstract Synopsis

The anisotropy of the slip length and its effect on the skin-friction drag are numerically investigated for a turbulent channel flow with an idealized superhydrophobic surface having an air layer, where the idealized air–water interface is flat and does not contain the surface-tension effect. Inside the air layer, both the shear-driven flow and recirculating flow with zero net mass flow rate are considered. With increasing air-layer thickness, the slip length, slip velocity and percentage of drag reduction increase. It is shown that the slip length is independent of the water flow and depends only on the air-layer geometry.

2015

The capillary adhesion technique: a versatile method for determining the liquid adhesion force and sample stiffness

by Gandyra, D., et al.

Topic: Shipcoating

Abstract Synopsis

We report a novel, practical technique for the concerted, simultaneous determination of both the adhesion force of a small structure or structural unit (e.g., an individual filament, hair, micromechanical component or microsensor) to a liquid and its elastic properties. The method involves the creation and development of a liquid meniscus upon touching a liquid surface with the structure, and the subsequent disruption of this liquid meniscus upon removal.

2014

Third IMO Greenhouse Gas Study

by IMO

Topic: Emissions

Abstract Synopsis

This study of greenhouse gas emissions from ships (hereafter the Third IMO GHG Study 2014) was commissioned as an update of the International Maritime Organization’s (IMO) Second IMO GHG Study 2009. The updated study has been prepared on behalf of IMO by an international consortium led by the University College London (UCL) Energy Institute. The Third IMO GHG Study 2014 was carried out in partnership with the organizations and individuals listed below.

Infinite lifetime of underwater superhydrophobic states

by Xu, M., G. Sun, and C.-J. Kim

Abstract Synopsis

Submerged superhydrophobic (SHPo) surfaces are well known to transition from the dewetted to wetted state over time. Here, a theoretical model is applied to describe the depletion of trapped air in a simple trench and rearranged to prescribe the conditions for infinite lifetime. By fabricating a microscale trench in a transparent hydrophobic material, we directly observe the air depletion process and verify the model. The study leads to the demonstration of infinite lifetime (> 50 days) of air pockets on engineered microstructured surfaces under water for the first time. Environmental fluctuations are identified as the main factor behind the lack of a long-term underwater SHPo state to date.

2013

Extraordinary drag-reducing effect of a superhydrophobic coating on a macroscopic model ship at high speed

by Dong, H., et al

Topic: Shipcoating

Abstract Synopsis

We have fabricated a self-cleaning coating on a model ship with a large and curved surface by electroless deposition of gold aggregates, and the superhydrophobic model ship exhibited a remarkable drag reduction of 38.5% at a velocity of 0.46 m s−1. The as-prepared coating exhibits excellent superhydrophobic properties, with a contact angle as high as 159.7°. To rule out the influence of wetting area differences between superhydrophobic coated materials and normal materials, we modified the large curved surface of a model ship with the self-cleaning coating and investigated its drag reducing properties at high speed. The results showed that the superhydrophobic coating took effect in reducing drag; the mechanism of the drag reduction is discussed based on the plastron effect and Newton’s law of viscosity.

The evolution of shipping emissions and the costs of regulation changes in the northern EU area.

by Johansson, L., et al

Topic: Emissions

Abstract Synopsis

An extensive inventory of marine exhaust emissions is presented in the northern European emission control area (ECA) in 2009 and 2011. The emissions of SOx, NOx, CO2, CO and PM2.5 were evaluated using the Ship Traffic Emission Assessment Model (STEAM). We have combined the information on individual vessel characteristics and position reports generated by the automatic identification system (AIS). The emission limitations from 2009 to 2011 have had a significant impact on reducing the emissions of both SOx and PM2.5.

2012

The hydrodynamic function of shark skin and two biomimetic applications

by Oeffner, J. and G.V. Lauder

Topic: Biomimicry

Abstract Synopsis

It has long been suspected that the denticles on shark skin reduce hydrodynamic drag during locomotion, and a number of man-made materials have been produced that purport to use shark-skin-like surface roughness to reduce drag during swimming. But no studies to date have tested these claims of drag reduction under dynamic and controlled conditions in which the swimming speed and hydrodynamics of shark skin and skin-like materials can be quantitatively compared with those of controls lacking surface ornamentation or with surfaces in different orientations. We use a flapping foil robotic device that allows accurate determination of the self-propelled swimming (SPS) speed of both rigid and flexible membrane-like foils made of shark skin and two biomimetic models of shark skin to measure locomotor performance.

Extension of an assessment model of ship traffic exhaust emissions for particulate matter and carbon monoxide

by Jalkanen, J.-P., et al.

Topic: Emissions

Abstract Synopsis

A method is presented for the evaluation of the exhaust emissions of marine traffic, based on the messages provided by the Automatic Identification System (AIS), which enable the positioning of ship emissions with a high spatial resolution (typically a few tens of metres). The model also takes into account the detailed technical data of each individual vessel. The previously developed model was applicable for evaluating the emissions of NOx, SOx and CO2. This paper addresses a substantial extension of the modelling system, to allow also for the mass-based emissions of particulate matter (PM) and carbon monoxide (CO).

2011

White Paper on Transport: Roadmap to a Single European Transport Area: Towards a Competitive and Resource-efficient Transport System

by European Commission

Topic: Shipping

Abstract Synopsis

This strategic document presents the Commission’s vision for the future of the EU transport system and defines a policy agenda for the next decade. The programme in question is part of the Europe 2020 strategy and its flagship initiative for a resource efficient Europe.

Superhydrophobic surfaces of water bug Notonecta: model for friction reduction and air retention

by Ditsche-Kuru, P., et al.

Topic: Biomimicry

Abstract Synopsis

Superhydrophobic surfaces of plants and animals are of great interest for biomimetic applications. Whereas the self-cleaning properties of superhydrophobic surfaces have been extensively investigated, their ability to retain an air film while submerged under water has not, in the past, received much attention. Nevertheless, air retaining surfaces are of great economic and ecological interest because an air film can reduce friction of solid bodies sliding through the water. This opens perspectives for biomimetic applications such as low friction fluid transport or friction reduction on ship hulls.

Reducing Greenhouse Gas Emissions from Ships

by ICCT

Topic: Emissions

Abstract Synopsis

Marginal abatement cost (MAC) curves are a staple of policy discussions
where there is a need to illustrate the incremental contributions of parts to
a whole. In this instance, they provide a simple and elegant way to illustrate
greenhouse gas (GHG) emission reductions from design standards, retrofit
technologies, and operational measures that improve ship energy efficiency
relative to their costs.

2010

The Salvinia paradox: superhydrophobic surfaces with hydrophilic pins for air retention under water

by Barthlott, W., et al.

Topic: Biomimicry

Abstract Synopsis

A novel mechanism for long‐term air retention under water is found in the sophisticated surface design of the water fern Salvinia. Its floating leaves are evenly covered with complex hydrophobic hairs retaining a layer of air when submerged under water. Surprisingly the terminal cells of the hairs are hydrophilic. These hydrophilic patches stabilize the air layer by pinning the air–water interface. This “Salvinia Effect” provides an innovative concept to develop biomimetic surfaces with long‐term air‐retention capabilities for under water applications.

Designing biomimetic antifouling surfaces

by Salta, M., et al.

Topic: Biofouling / Biomimicry

Abstract Synopsis

Marine biofouling is the accumulation of biological material on underwater surfaces, which has plagued both commercial and naval fleets. Biomimetic approaches may well provide new insights into designing and developing alternative, non-toxic, surface-active antifouling (AF) technologies. In the marine environment, all submerged surfaces are affected by the attachment of fouling organisms, such as bacteria, diatoms, algae and invertebrates, causing increased hydrodynamic drag, resulting in increased fuel consumption, and decreased speed and operational range. There are also additional expenses of dry-docking, together with increased fuel costs and corrosion, which are all important economic factors that demand the prevention of biofouling. Past solutions to AF have generally used toxic paints or coatings that have had a detrimental effect on marine life worldwide. The prohibited use of these antifoulants has led to the search for biologically inspired AF strategies. This review will explore the natural and biomimetic AF surface strategies for marine systems.

2009

Health risks of shipping pollution have been 'underestimated'

by The Guardian

Topic: missions

2008

International Convention on the Control of Harmful Anti-fouling Systems on Ships, International Maritime Organization (IMO)

by IMO

Topic: Biofouling / Biomimicry

Abstract Synopsis

​The Convention prohibits the use of harmful organotins in anti-fouling paints used on ships and establishes a mechanism to prevent the potential future use of other harmful substances in anti-fouling systems.

Anti-fouling paints are used to coat the bottoms of ships to prevent sealife such as algae and molluscs attaching themselves to the hull – thereby slowing down the ship and increasing fuel consumption.

2006

On the interaction of compliant coatings with boundary-layer flows

by Gad-El-Hak, M., R.F. Blackwelder, and J.J. Riley

Topic: Shipcoating

Abstract Synopsis

The interactions of compliant coatings with laminar, transitional and turbulent boundary layers are investigated. A 2 m long flat plate is towed in the range of speeds of 20–140 cm/s in an 18 m water channel using a carriage riding on an oil film. Isotropic and anistropic compliant coatings are used to cover about 20% of the working Plexiglas surface. The compliant material used is a viscoelastic plastisol gel produced by heating a mixture of polyvinyl chloride resin, a plasticizer and a stabilizer, and allowing them to gel. The shear modulus of rigidity of the plastisol was varied by changing the percentage of PVC in the mix. Anisotropy is introduced by placing the plastisol on a rubber surface having longitudinal grooves scaled with the low-speed streaks in the turbulent boundary layer.

PROJECT COORDINATOR

Johannes Oeffner
Fraunhofer CML
Johannes.Oeffner@cml.fraunhofer.de

COMMUNICATION CONTACT

Hadil J.S. Ayoub
REVOLVE
hadil@revolve.media

The AIRCOAT project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement N°764553.

PROJECT COORDINATOR

Johannes Oeffner
Fraunhofer CML
Johannes.Oeffner@cml.fraunhofer.de

COMMUNICATION CONTACT

Hadil J.S. Ayoub
REVOLVE
hadil@revolve.media

The AIRCOAT project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement N°764553.