Passive autocatalytic recombiner (PAR) is a device that removes hydrogen from the containment of a nuclear power plant during an accident. Its purpose is to prevent hydrogen explosions. Recombiners come into action spontaneously as soon as the hydrogen concentration increases. They are passive devices because their operation does not require external energy.Hydrogen may be generated in a nuclear accident if the reactor fuel overheats and zirconium cladding of the fuel rods reacts chemically with steam. If the hydrogen is released from the reactor to the containment, it may get mixed with air and form a flammable or even explosive mixture. A hydrogen explosion could break the containment and cause radioactive materials to be released to the environment. Recombiners aim at removing hydrogen and thereby preventing explosions.Inside a recombiner there are plates or pellets that are coated with platinum or palladium catalyst. On the surface of the catalyst, hydrogen and oxygen molecules react chemically at low temperature and low hydrogen concentration. The reaction generates steam. The reaction starts spontaneously when the hydrogen concentration reaches 1...

Passive autocatalytic recombiner (PAR) is a device that removes hydrogen from the containment of a nuclear power plant during an accident. Its purpose is to prevent hydrogen explosions. Recombiners come into action spontaneously as soon as the hydrogen concentration increases. They are passive devices because their operation does not require external energy.Hydrogen may be generated in a nuclear accident if the reactor fuel overheats and zirconium cladding of the fuel rods reacts chemically with steam. If the hydrogen is released from the reactor to the containment, it may get mixed with air and form a flammable or even explosive mixture. A hydrogen explosion could break the containment and cause radioactive materials to be released to the environment. Recombiners aim at removing hydrogen and thereby preventing explosions.Inside a recombiner there are plates or pellets that are coated with platinum or palladium catalyst. On the surface of the catalyst, hydrogen and oxygen molecules react chemically at low temperature and low hydrogen concentration. The reaction generates steam. The reaction starts spontaneously when the hydrogen concentration reaches 1...

Eucalyptol is a monoterpenoid. A colorless liquid, it is a bicyclic ether. Eucalyptol has a fresh mint-like smell and a spicy, cooling taste. It is insoluble in water, but miscible with organic solvents. Eucalyptol makes up ~70–90% of eucalyptus oil. Eucalyptol forms crystalline adducts with hydrohalic acids, o-cresol, resorcinol, and phosphoric acid. Formation of these adducts is useful for purification.In 1870, F. S. Cloez identified and ascribed the name "eucalyptol" to the dominant portion of Eucalyptus globulus oil. Uses Because of its pleasant, spicy aroma and taste, eucalyptol is used in flavorings, fragrances, and cosmetics. Cineole-based eucalyptus oil is used as a flavouring at low levels (0.002%) in various products, including baked goods, confectionery, meat products, and beverages. In a 1994 report released by five top cigarette companies, eucalyptol was listed as one of the 599 additives to cigarettes. It is claimed to be added to improve the flavor. Eucalyptol is an ingredient in commercial mouthwashes, and has been used in traditional medicine as a cough suppressant. ...

Kendang or Gendang (Javanese: ꦏꦼꦤ꧀ꦝꦁ, romanized: Kendhang, Sundanese: ᮊᮨᮔ᮪ᮓᮀ, romanized: Kendang, Balinese: ᬓᬾᬦ᭄ᬤᬂ, romanized: Kendang, Tausug/Bajau/Maranao: Gandang, Bugis: Gendrang and Makassar: Gandrang or Ganrang ) is a two-headed drum used by people from the Indonesian Archipelago. Kendang is one of the primary instruments used in the Gamelan ensembles of Javanese, Sundanese, and Balinese, the Kendang ensemble as well as various Kulintang ensembles in Indonesia, Brunei, Malaysia, Singapore, and the Philippines. It is constructed in a variety of ways by different ethnic groups. It is a relation to the Indian mridangam double-headed drum. ...

Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for animal). Plankton are aquatic organisms that are unable to swim effectively against currents. Consequently, they drift or are carried along by currents in the ocean, or by currents in seas, lakes or rivers. Zooplankton can be contrasted with phytoplankton, which are the plant component of the plankton community ("phyto" comes from the Greek word for plant). Zooplankton are heterotrophic (other-feeding), whereas phytoplankton are autotrophic (self-feeding). In other words, zooplankton cannot manufacture their own food. Rather, they must eat other plants or animals instead. In particular, they eat phytoplankton, which are generally smaller than zooplankton. Most zooplankton are microscopic but some (such as jellyfish) are macroscopic, meaning they can be seen with the naked eye.Many protozoans (single-celled protists that prey on other microscopic life) are zooplankton, including zooflagellates, foraminiferans, radiolarians, some dinoflagellates and marine microanimals. Macroscopic zooplankton include pelagic cnidarians, ctenophores, molluscs, arthropods...

Pierre Curie ( KURE-ee, French: [pjɛʁ kyʁi]; 15 May 1859 – 19 April 1906) was a French physicist, a pioneer in crystallography, magnetism, piezoelectricity, and radioactivity. In 1903, he received the Nobel Prize in Physics with his wife, Marie Skłodowska–Curie, and Henri Becquerel, "in recognition of the extraordinary services they have rendered by their joint researches on the radiation phenomena discovered by Professor Henri Becquerel". With their win, the Curies became the first ever married couple to win the Nobel Prize, launching the Curie family legacy of five Nobel Prizes. Early life Born in Paris on 15 May 1859, Pierre Curie was the son of Eugène Curie (1827–1910), a doctor of French Catholic origin from Alsace, and Sophie-Claire Curie (née Depouilly; 1832–1897). He was educated by his father and in his early teens showed a strong aptitude for mathematics and geometry. When he was 16, he earned his...

The Orto Botanico di Padova is a botanical garden in Padua, in the northeastern part of Italy. Founded in 1545 by the Venetian Republic, it is the world's oldest academic botanical garden that is still in its original location. The garden – operated by the University of Padua and owned by the Italian government – encompasses roughly 22,000 square meters, and is known for its special collections and historical design. History The Garden of Padua was founded upon deliberation of the Senate of the Venetian Republic. It was devoted to the growth of medicinal plants, the so-called "simple plants" (Orto dei semplici - simples were herbs that were used as they are rather than in admixtures) which produced natural remedies, and also to help students distinguish genuine medicinal plants from false ones. A circular wall enclosure was built to protect the garden from the frequent night thefts which occurred in spite of severe penalties (fines, prison, exile). The Botanical Garden was steadily enriched with plants from all over the world, particularly from the countries that participated in trade with Venice. Consequently, Padua...

A chamberlain (Medieval Latin: cambellanus or cambrerius, with charge of treasury camerarius) is a senior royal official in charge of managing a royal household. Historically, the chamberlain superintends the arrangement of domestic affairs and was often also charged with receiving and paying out money kept in the royal chamber. The position was usually awarded as an honour to a high-ranking member of the nobility (nobleman) or the clergy, often a royal favourite. Roman emperors appointed this officer under the title of cubicularius. The Chamberlain of the Holy Roman Church enjoys very extensive powers, having the revenues of the papal household under his charge. As a sign of their dignity, chamberlains bore a key, which in the seventeenth century was often silvered, and actually fitted the door-locks of chamber rooms. Since the eighteenth century, it has turned into a merely symbolic, albeit splendid, rank-insignia of gilded bronze. In many countries there are ceremonial posts associated with the household of the sovereign. Description Historically, many institutions and governments – monasteries...

Stibnite, sometimes called antimonite, is a sulfide mineral with the formula Sb2S3. This soft grey material crystallizes in an orthorhombic space group. It is the most important source for the metalloid antimony. The name is derived from the Greek στίβι stibi through the Latin stibium as the former name for the mineral and the element antimony. Structure Stibnite has a structure similar to that of arsenic trisulfide, As2S3. The Sb(III) centers, which are pyramidal and three-coordinate, are linked via bent two-coordinate sulfide ions. However, some studies suggest that the actual coordination polyhedra of antimony are SbS7, with (3+4) coordination at the M1 site and (5+2) at the M2 site. Some of the secondary bonds impart cohesion and are connected with packing. Stibnite is grey when fresh, but can turn superficially black due to oxidation in air. Properties The melting point of Sb2S3 is 823 K (550 °C; 1,022 °F). The band gap is 1.88 eV at room temperature and it is a photoconductor...