3 May 2019 Bulletin

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Diesel Exhaust

Diesel is a type of fuel derived from crude oil. Large engines, including those used in many trucks, buses, trains, construction and farm equipment, generators, ships, and in some cars, run on diesel fuel. [1] Diesel engines convert the chemical energy contained in the fuel into mechanical power. Diesel fuel is injected under pressure into the engine cylinder where it mixes with air and where the combustion occurs. The exhaust gases which are discharged from the engine contain several constituents that are harmful to human health and to the environment. [2] The exhaust from diesel engines is made up of 2 main parts: gases and soot. Each of these, in turn, is made up of many different substances. The gas portion of diesel exhaust is mostly carbon dioxide, carbon monoxide, nitric oxide, nitrogen dioxide, sulphur oxides, and hydrocarbons, including polycyclic aromatic hydrocarbons (PAHs). The soot (particulate) portion of diesel exhaust is made up of particles such as carbon, organic materials (including PAHs), and traces of metallic compounds. Both the gases and the soot of diesel exhaust contain PAHs. [1]



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ECHA releases new submission portal for poison centres

The European Chemicals Agency (ECHA) has released a new portal that allows companies to prepare and submit information on hazardous mixtures that can be used by poison centres. ECHA’s submission portal for poison centres is a secure, online way to centrally manage notifications – creating, submitting and following their status. It is based on the harmonised format which defines the information requirements set in the CLP Regulation. The portal allows companies to notify several Member States in which they intend to place their products on the market with a single submission. This will reduce companies’ administrative burden and costs when submitting information on hazardous mixtures to appointed bodies in EU Member States and EEA countries. ECHA is not charging a fee for the use of the portal but some Member States may levy fees to cover their costs. Notifications submitted through the portal will be valid once the relevant Member State is ready to accept them. Further improvements to the user interface and more functionalities will be implemented in future releases of the portal in July and November 2019.

Under the Classification, Labelling and Packaging (CLP) Regulation, companies placing hazardous mixtures on the market have to provide information about these mixtures to the relevant national appointed bodies. This information has to be provided in a harmonised format from 1 January 2020 for mixtures for consumer use, from 1 January 2021 for mixtures for professional use, and from 1 January 2024 for mixtures for industrial use. The appointed bodies in Member States make this information available to poison centres so that they can provide rapid medical advice in the event of an emergency. Further information is available at:




Jellyfish-inspired electronic skin can heal itself while wet

A new electronic skin that is transparent, stretchable, touch-sensitive, and self-healing in aquatic environments gets its inspiration from jellyfish. “One of the challenges with many self-healing materials today is that they are not transparent and they do not work efficiently when wet,” says Benjamin Tee, assistant professor of materials science and engineering at the National University of Singapore. “These drawbacks make them less useful for electronic applications such as touchscreens which often need to be used in wet weather conditions. “With this idea in mind, we began to look at jellyfishes—they are transparent, and able to sense the wet environment. So, we wondered how we could make an artificial material that could mimic the water-resistant nature of jellyfishes and yet also be touch sensitive,” says Tee, who has worked on electronic skins for many years and was part of the team that developed the first ever self-healing electronic skin sensors in 2012. The researchers created a gel consisting of a fluorocarbon-based polymer with a fluorine-rich ionic liquid. When researchers combine the two, the polymer network interacts with the ionic liquid via highly reversible ion-dipole interactions, which allows it to self-heal. “Most conductive polymer gels such as hydrogels would swell when submerged in water or dry out over time in air,” Tee says. “What makes our material different is that it can retain its shape in both wet and dry surroundings. It works well in sea water and even in acidic or alkaline environments.” To create the electronic skin, the team printed the material into electronic circuits. As a soft and stretchable material, its electrical properties change when touched, pressed, or strained. “We can then measure this change, and convert it into readable electrical signals to create a vast array of different sensor applications,” says Tee, who is also from the NUS Biomedical Institute for Global Health Research and Technology. “The 3D printability of our material also shows potential in creating fully transparent circuit boards that could be used in robotic applications. We hope that this material can be used to develop various applications in emerging types of soft robots.” Soft robots, and soft electronics in general, aim to mimic biological tissues to make them more mechanically compliant for human-machine interactions. In addition to conventional soft robot applications, the material’s waterproof technology enables the design of amphibious robots and water-resistant electronics. Another advantage of the skin is its potential to reduce waste. “Millions of tonnes of electronic waste from devices like broken mobile phones or tablets are generated globally every year. We are hoping to create a future where electronic devices made from intelligent materials can perform self-repair functions to reduce the amount of electronic waste in the world,” Tee says. Tee and his team are hoping to explore further possibilities of the material. “Currently, we are making use of the comprehensive properties of the material to make novel optoelectronic devices, which could be utilised in many new human-machine communication interfaces,” he says. The study appears in Nature Electronics. Additional co-authors are from Tsinghua University and the University of California, Riverside.



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