22 November 2019 Bulletin

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Lead

Lead is a chemical element in the carbon group with symbol Pb and atomic number 82. Lead is a soft and malleable metal, which is regarded as a heavy metal. Metallic lead has a bluish-white colour after being freshly cut, but it soon tarnishes to a dull greyish colour when exposed to air. Lead has a shiny chrome-silver lustre when it is melted into a liquid. [1] Lead is found in the earth's crust. However, it is rarely found naturally as a metal. It is usually found combined with two or more other elements to form lead compounds. Metallic lead is resistant to corrosion (i.e., not easily attacked by air or water). When exposed to air or water, thin films of lead compounds are formed that protect the metal from further attack. Lead is easily moulded and shaped. Lead can be combined with other metals to form alloys. [2]

 


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Featured Articles

EU gives Ireland the green light to introduce microbead ban

The European Union (EU) has cleared the way for the Irish Government to introduce laws which be ban microbeads. Minister Eoghan Murphy announced the European Commission’s clearance for the restrictions on microbeads contained in the Microbeads (Prohibition) Bill 2019. The minister welcomed the green light from the European Commission for his proposals. This will now facilitate further consideration of the bill at committee stage in the Dáil. The bill will provide for a ban on the manufacture, import, export or sale of products containing intentionally added plastic microbeads, to include “rinse-off” personal care products, detergents, and domestic and industrial abrasive cleaning products and scouring agents. Murphy said: “Now that the standstill period has been concluded, I look forward to working with my Oireachtas colleagues at Committee Stage at the earliest opportunity so that we can have this bill in force as soon as possible. “While several States legislated to prohibit personal care products containing plastic microbeads Ireland will be the first EU Member State to extend such prohibition to detergents, abrasive scouring agents and other cleaning products.” Murphy added that plastic microbeads represent only one element of the microplastics in our oceans. It is estimated that many billions are being washed down the drain and into the world’s rivers, lakes and seas each year. Once in our rivers and seas, they can last for centuries without breaking down. Aquatic animals may ingest them and they cannot be removed once they are in the marine environment. Murphy added: “I am increasingly concerned about the potential risk posed to our aquatic ecosystems by microplastic litter, including plastic microbeads. I know this concern is shared widely, across all parties in the Oireachtas and throughout broader society. “While this is an important step, it is only one of many measures we will have to introduce over the coming years to reduce the level of litter and plastic pollution entering our seas and oceans.

https://www.thejournal.ie/

 

Electric cloth

Evening gowns with interwoven LEDs may look extravagant, but the light sources need a constant power supply from devices that are as well wearable, durable, and lightweight. Chinese scientists have manufactured fibrous electrodes for wearable devices that are flexible and excel by their high energy density. A microfluidic technology was key for the preparation of the electrode material was a microfluidic technology, as shown in the journal Angewandte Chemie. Dresses sparkling light from hundreds of small LEDs may create eye-catching effects in ballrooms or on fashion shows. But wearable electronics can also mean sensors integrated in functional textiles to monitor, for example, water evaporation or temperature changes. Energy storage systems powering such wearable devices must combine deformability with high capacity and durability. However, deformable electrodes often fail in long-term operation, and their capacity lags behind that of other state-of-the-art energy storage devices. Electrode materials usually benefit from a fine balance of porosity, conductivity, and electrochemical activity. Material scientists Su Chen, Guan Wu, and their teams from the Nanjing Tech University, China, have looked deeper into the material demands for flexible electrodes and developed a porous hybrid material synthesized from two carbon nanomaterials and a metal-organic framework. The nanocarbons provided the large surface area and excellent electrical conductivity, and the metalorganic framework gave the porous structure and the electrochemical activity. To make the electrode materials flexible for wearable applications, the micro-mesoporous carbon frameworks were spun into fibres with a thermoplastic resin by using an innovative blow-spinning machine. The resulting fibres were pressed into cloths and assembled into supercapacitors, although it turned out that another round of coating with the micro-mesoporous carbon frameworks further improved the electrode performances. The supercapacitors made from these electrodes were not only deformable, but they could also harbor higher energy densities and larger specific capacitances than comparable devices. They were stable and endured more than 10,000 charge-discharge cycles. The scientists also tested them in practical applications such as smart colour switching of LEDs in dresses and solar-cell-controlled powering of electronic devices integrated in functional clothing. The authors pointed out that the microfluidic droplet-based synthesis was key to improving the performance of the electrode materials for wearable electronics. It was all about adjusting the perfect porous nanostructure, they argued.

https://www.eurekalert.org/

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