Khatyrka, a new CV3 find from the Koryak Mountains, Eastern Russia

A new meteorite find, named Khatyrka, was recovered from eastern Siberia as a result of a search for naturally occurring quasicrystals. The meteorite occurs as clastic grains within postglacial clay-rich layers along the banks of a small stream in the Koryak Mountains, Chukotka Autonomous Okrug of far eastern Russia. Some of the grains are clearly chondritic and contain Type IA porphyritic olivine chondrules enclosed in matrices that have the characteristic platy olivine texture, matrix olivine composition, and mineralogy (olivine, pentlandite, nickel-rich iron-nickel metal, nepheline, and calcic pyroxene [diopside-hedenbergite solid solution]) of oxidized-subgroup CV3 chondrites. A few grains are fine-grained spinel-rich calcium-aluminum-rich inclusions with mineral oxygen isotopic compositions again typical of such objects in CV3 chondrites. The chondritic and CAI grains contain small fragments of metallic copper-aluminum-iron alloys that include the quasicrystalline phase icosahedrite. One grain is an achondritic intergrowth of Cu-Al metal alloys and forsteritic olivine ± diopsidic pyroxene, both of which have meteoritic (CV3-like) oxygen isotopic compositions. Finally, some grains consist almost entirely of metallic alloys of aluminum + copper ± iron. The Cu-Al-Fe metal alloys and the alloy-bearing achondrite clast are interpreted to be an accretionary component of what otherwise is a fairly normal CV3 (oxidized) chondrite. This association of CV3 chondritic grains with metallic copper-aluminum alloys makes Khatyrka a unique meteorite, perhaps best described as a complex CV3 (ox) breccia

Розподіл вимог до надійності технічного об'єкта між його вузлами і агрегатами

Капица М. И. Распределение требований к надежности технического объекта между его узлами и агрегатами / М. И. Капица, В. А. Крячко // Вісник Східноукр. нац. ун-ту ім. В. Даля . - 2011. – №4 (158). – С. 60-66.RU: Рассматривается вопрос о предъявлении требований к на¬дежности отдельных узлов и агрегатов технического объекта на этапе эскизного проектирования для случая, когда требования по надежности системы в целом известны. UK: Предложенный метод позволяет проиллюстрировать распределение требований к восстанавливаемости отдельных УА технического объекта, а так же определять, сколько времени будет затрачено на ремонт отдельно взятого УА технического объекта с учетом заданного времени на отказ. EN: Розглядається питання з пред'явленням вимог до надійності окремих вузлів і агрегатів технічного об'єкту на етапі ескізного проектування для випадку, коли вимоги по надійності системи в цілому відомі. EN: A question is examined about producing of requirements to reliability of separate knots and aggregates of technical object on the stage of the preliminary planning for a case, when requirement on reliability of the system on the whole known

Natural quasicrystal with decagonal symmetry

We report the first occurrence of a natural quasicrystal with decagonal symmetry. The quasicrystal, with composition Al71Ni24Fe5, was discovered in the Khatyrka meteorite, a recently described CV3 carbonaceous chondrite. Icosahedrite, Al63Cu24Fe13, the first natural quasicrystal to be identified, was found in the same meteorite. The new quasicrystal was found associated with steinhardtite (Al38Ni32Fe30), Fe-poor steinhardtite (Al50Ni40Fe10), Al-bearing trevorite (NiFe2O4) and Al-bearing taenite (FeNi). Laboratory studies of decagonal Al71Ni24Fe5 have shown that it is stable over a narrow range of temperatures, 1120 K to 1200 K at standard pressure, providing support for our earlier conclusion that the Khatyrka meteorite reached heterogeneous high temperatures [1100 < T(K) ≤ 1500] and then rapidly cooled after being heated during an impact-induced shock that occurred in outer space 4.5 Gya. The occurrences of metallic Al alloyed with Cu, Ni, and Fe raises new questions regarding conditions that can be achieved in the early solar nebula

Impact-induced shock and the formation of natural quasicrystals in the early solar system

The discovery of a natural quasicrystal, icosahedrite (Al_(63)Cu_(24)Fe_(13)), accompanied by khatyrkite (CuAl_2) and cupalite (CuAl) in the CV3 carbonaceous chondrite Khatyrka has posed a mystery as to what extraterrestrial processes led to the formation and preservation of these metal alloys. Here we present a range of evidence, including the discovery of high-pressure phases never observed before in a CV3 chondrite, indicating that an impact shock generated a heterogeneous distribution of pressures and temperatures in which some portions reached at least 5 GPa and 1,200 °C. The conditions were sufficient to melt Al–Cu-bearing minerals, which then rapidly solidified into icosahedrite and other Al–Cu metal phases. The meteorite also contains heretofore unobserved phases of iron–nickel and iron sulphide with substantial amounts of Al and Cu. The presence of these phases in Khatyrka provides further proof that the Al–Cu alloys are natural products of unusual processes that occurred in the early solar system