Publikace

Co je Nordic Gold (nordické zlato)?

Slitina s 89% mědi, 5% hliníku, 5% zinku a 1% cínu. Tuto slitinu používají mince 10, 20 a 50 eurocentů.

Co je směs Bordeaux?

Když francouzský vědec Millardet hledal lék na plísněmi napadené vinice ve francouzském Bordeaux, náhodou si všiml, že ty vinice, které hraničí se silnicí a které byly pomazány pastou ze síranu měďnatého a vápna ve vodě, aby byly hrozny neatraktivní pro kolemjdoucí, se zdály plísní méně napadené. Toto pozorování vedlo k experimentům se směsí síranu měďnatého, vápna a vody, a v roce 1885 Millardet oznámil světu, že našel lék na obávané plísně. Ten se stal známý jako směs Bordeaux a zahájil věk ochranných postřiků.

Co se rozumí pod pojmem "antimikrobiální"?

„Antimikrobiální“ je schopnost látky zabít nebo inaktivovat mikroorganismy jako jsou bakterie, houby (včetně plísní) a viry.

Člověk využívá přirozené antimikrobiální vlastnosti mědi již od úsvitu civilizace.  V mnoha vědeckých studiích, provedených v průběhu několika desetiletí, bylo jasně prokázáno, že měď má rychlé a široké spektrum antimikrobiálních účinků proti některým z nejvíce toxických druhů bakterií, plísní a virů.

Co se rozumí pod pojmem "účinnější" přenos tepla?

Stejné nebo lepší výsledky lze dosáhnout s méně materiálem na trubky a žebra. Jinými slovy, méně materiálem je přeneseno více tepla. Méně trubek, více tepla! Z technického hlediska lze výměníky s menším průměrem trubky navrhovat s vyšším „součinitelem prostupu tepla“ oproti výměníku s větším průměrem trubek.

Has copper been tested in clinical trials?

Yes. Copper surfaces have been proven to have over 90% less contamination than conventional touch surfaces in hospital trials around the world.  Trials have taken place, or are under way, in China, France, Germany, Greece, Japan, Spain, South Africa, Chile and the US.

Furthermore, in a multi-centre US trial, funded by the Department of Defense, copper surfaces were shown to reduce a patient’s risk of acquiring a healthcare-associated infection by 58%.

How can bronze works of art be protected from corrosion if they are situated outdoors?

Either by the use of lacquers, wax polishing, or both.

How can corrosion or staining of machined aluminium bronze components be avoided during shipping?

The key is to clean them thoroughly, remove water, protect them and keep them dry, so:

  1. After cleaning dry thoroughly using a dewatering fluid such as WD40.
  2. Remove displaced water with forced warm air.
  3. Coat with a protective coating such as benzotriazole inhibitor, or a block co-polymer.
  4. Pack into benzotriazole treated paper lined wooden boxes. Moisture absorbent granules may also be used to keep the air inside the boxes dry.

When unpacked, remove the coatings with a phosphoric-based solution and dry them thoroughly.

How is Bordeaux mixture prepared?

Bordeaux mixture is prepared in various strengths from copper sulphate, hydrated lime (calcium hydroxide) and water. The conventional method of describing its composition is to give the weight of copper sulphate, the weight of hydrated lime and the volume of water in that order.

The percentage of copper sulphate weight to the weight of water employed determines the concentration of the Bordeaux mixture. A 1% Bordeaux mixture, which is the norm, would have the formula 1 :1:100, the first 1 representing 1 kg copper sulphate, the second representing 1 kg hydrated lime, and the 100 representing 100 litres (100 kg) water.

As copper sulphate contains 25% copper metal, the copper content of a 1% Bordeaux mixture would be 0-25% copper. The quantity of lime used can be reduced considerably. 1 kg copper sulphate requires only 0.225 kg of chemically pure hydrated lime to precipitate all the copper. Good proprietary brands of hydrated lime are now freely available but, as even these deteriorate on storage, it is safest not to exceed a ratio of 2:1, i.e. a 1:0.5:100 mixture.

In preparing Bordeaux mixture, the copper sulphate is dissolved in half the required amount of water in a wooden or plastic vessel. The hydrated lime is mixed with the balance of the water in another vessel. The two ‘solutions’ are then poured together through a strainer into a third vessel or spray tank.

How is copper used on a farm?

Copper sulphate, because of its fungicidal and bactericidal properties, has been employed as a disinfectant on farms against storage rots and for the control and prevention of certain animal diseases, such as foot rot of sheep and cattle.

How long has copper been used in agriculture?

The first recorded use was in 1761, when it was discovered that seed grains soaked in a weak solution of copper sulphate inhibited seed-borne fungi.

How long has copper plumbing been used?

The earliest recorded use of copper for conveying water is a water conduit in Abusir, Egypt, which dates back to 2750 BC and is still in a good state of preservation. Copper water pipes and cisterns were widely used by the Romans – examples can be found at the archaeological site of Herculaneum, destroyed by the eruption of Vesuvius in 79AD. At the beginning of this century, copper started being used again in Europe and North America.

How many copper alloys are available for aquaculture so far?

Three. They are: Copper-Zinc, Copper-Nickel, and Copper-Silicon.