Irradiation is exposition of food to the action of gamma rays, in order to preserve it longer. It is especially used for fruit.
Lower flammable limit (LEL) or the lower explosive limit is the minimum concentration of vapour or gas in air above which propagation of flame does not occur on contact with a source of ignition. The mixture is said to be too lean.
Neon was discovered by Sir William Ramsay and Morris W. Travers (England) in 1898. The origin of the name comes from the Greek word neon meaning new. It is colourless, odourless inert gas. Non-reactive even with fluorine. Fourth most abundant element in the universe. Neon is obtained by liquefaction of air and separated from the other gases by fractional distillation. Primarily for lighting.
Cadmium was discovered by Friedrich Strohmeyer (Germany) in 1817. The origin of the name comes from the Latin word cadmia meaning calamine (zinc carbonate, ZnCO3), or from the Greek word kadmeia with the same meaning. It is soft, malleable, blue-white metal. Tarnishes in air, soluble in acids, insoluble in alkalis. Boiling cadmium gives off a weird, yellow-colored vapour that is poisonous. Cadmium can cause a variety of health problems, including kidney failure and high blood pressure. Cadmium is obtained as a by product of zinc refining. The mayor use of cadmium is in electroplating of steel to protect it from corrosion. Also used to make nickel-cadmium batteries. The ability of cadmium to adsorb neutrons has made it of great importance in the design of nuclear reactors. Its compounds are found in paint pigments and a wide variety of intense colours.
Caesium was discovered by Robert Bunsen and Gustav Kirchhoff (Germany) in 1860. The origin of the name comes from the Latin word caesius meaning sky blue or heavenly blue. It is very soft, light grey, ductile metal. Reacts readily with oxygen. Reacts explosively with water. Caesium is found in pollucite [(Cs4Al4Si9O26)·H2O] and as trace in lepidolite. Used as a ’getter’ to remove air traces in vacuum and cathode-ray tubes. Also used in producing photoelectric devices and atomic clocks. Since it ionises readily, it is used as an ion rocket motor propellant.
Carbon has been known since ancient times. The origin of the name comes from the Latin word carbo meaning charcoal. Graphite form of carbon is a black, odourless, slippery solid. Graphite sublimes at 3825 °C. Diamond form is a clear or colored; an extremely hard solid. C60 is Buckminsterfullerine. Carbon black burns readily with oxidants. Carbon is made by burning organic compounds with insufficient oxygen. There are close to ten million known carbon compounds, many thousands of which are vital to organic and life processes. Radiocarbon dating uses the carbon-14 isotope to date old objects.
Plastic welding is the fusion of two pieces (usually of the same plastic type) with a directed hot air jet and plastic welding rod. Used increasingly for the manufacture of tanks, floats and other items. Useful for repair of pipework (either temporary or permanent).
Radiation damage is a general term for the alteration of properties of a material arising from exposure to ionising radiation (penetrating radiation), such as X-rays, γ-rays, neutrons, heavy-particle radiation, or fission fragments in the nuclear fuel material.
Relative humidity is the ratio of the partial pressure of water vapour in air to the saturation vapour pressure of water at the same temperature, expressed as a percentage.
Cement is any various substances used for bonding or setting to a hard material. Portland cement is a mixture of calcium silicates and aluminates made by heating limestone (CaCO3) with clay (containing aluminosilicates) in a kiln. The product is ground to a fine powder. When mixed with water it settles in a few hours and then hardens over a longer period of time due to the formation of hydrated aluminates and silicates.
Generalic, Eni. "Spektar X-zraka." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
Glossary
Periodic Table