Coins, aluminium

The effective use of mobile cameras at the Thailand sites provided an experience that was remarkably similar to onsite supervision, allowing for real-time corrections and suggestions as readily as if all were present in the same laboratory. When Thai participants experienced difficulties in preparing a battery from copper and aluminium coins, for example, we noted that an inadvertent short eireuit had been formed, a problem that was quickly... 

Generally, it is the unreactive metals for which we find most uses. For example, the metals iron and copper can be found in everyday objects such as car bodies and coins, respectively However, the metal aluminium is an exception. Aluminium appears in the reactivity series just below magnesium and is quite reactive. 

Steel is an alloy containing chromium, manganese, molybdenum, nickel, vanadium and boron. Copper-nickel alloy, bronze and aluminium alloys are used in making coins. Fusible alloys having low melting points are used as solder and fuses in electrical circuits. 

In production the filled container—with the lid loosely applied—is fed into a vacuum chamber where a vacuum is first applied followed by a top loading to force the lid into intimate contact with the container rim. When the external pressure is restored to atmospheric, the vacuum within the container maintains the seal. The effectiveness of the closure can be checked visually or automatically by observing a depression in the lid due to the pressure differential. The container is opened by releasing the vacuum with the aid of a coin slot built into the base. Both container and lid are constructed of tinplate rather than aluminium and in a fairly thick gauge in order to withstand the pressures applied. 

Alloys of antimony and aluminium look very much like silver and have been used in the past in forging our coins. One such florin analysed by the author in 1911 contained aluminium 53 40, and antimony 46 38 per cent with traces of lead, arsenic and iron. With copper a violet alloy, probably a compound SbCuj, is formed known as regulus of Venus. Small amounts of antimony are used in stiffening lead. Antimony oxide is used, associated with titanium oxide, as a white pigment, as for example in titanox. 

I. Otsuki, Bussitsu no Henka (Matter and Change), Hyoronsha, Tokyo, 1973, (ISBN/ASIN 4566020045). This demonstration is particularly notable in that the functional battery produced from Japanese one yen (aluminium) and ten yen (copper) coins has the cathode and anode identified by the kanji characters for one (-) and ten (+). 

It was the chemist Louis Guyton de Morveau (1736-1816), a co-worker of Antoine Laurent Lavoisier (1743-1794), who coined the word alumine for one of the sulphates contained in alum. Alumine is derived from the Latin word alumen, which is said to have been used for potassium alum KAl(S04)2 l2H20 during Roman period. Aluminium compounds were used in large quantities in antique pottery, as dyestuff and as an astringent in medicine [1]. 

There have been a number of attempts to make OLEDs based on discotic liquid crystals although performance is disappointing probably because of aggregation. Wendorff and co-workers demonstrated monoesters of triphenylene 7, see Table 6.2, in their Colp phase and mainchain polymers of triphenylene in the Coin phase in electroluminescent devices. High electric fields were required, 10 V cm , and the lifetimes of the devices are probably not very long [40,41]. The bilayer devices made by Bock and co-workers, e.g., ITO/triphenylene 8 (hole transporter)/perylene 9 (electron transporter)/aluminium [43,44] exploit materials that have liquid crystal phases above room temperature [42, 43]. Simple variants on these structures were synthesised, which had green, blue and sometimes almost white light emission [44]. 

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