scholarly journals USE OF THREE-WALLED LOG HOUSES IN THE FORTIFICATIONS OF MEDIEVAL RUS

Author(s):  
В.Ю. Коваль

Предложен анализ использования довольно редко встречающейся в оборонном зодчестве конструкции из трехстенных срубов. Обзор представлений историков архитектуры и военного дела XIX−XX вв. сопровожден критикой их построений, исходивших из умозрительных представлений и следования схематичному изображению в труде Ласковского. В противовес этому собраны сведения о реально использовавшихся при строительстве древо-земляных стен трехстенных срубов («полугородней»), предназначавшихся преимущественно для вписывания укреплений в склоны холмов, рвов и т. п. Прослежен генезис этого строительного приема на протяжении 700 лет – с конца IХ по XVI в. The paper analyzes the use of a construction made from three-walled block houses which are rather rare in defense architecture. The overview of concepts offered by historians of architecture and warfare of the 19th–20th centuries is complemented by a critical review of their ideas. The latter were developed on the basis of some speculative notions and adherence to a schematic drawing in Laskvosky’s paper. By contrast with their efforts, information on three-walled log houses (half-gorodnyas) that were actually used for construction of the timber-earthen walls was collected. The task of these log houses was to ensure that fortifications were incorporated into hill, ditch sides, etc. The genesis of this construction technique in the period of 700 years, i.e. from late 9th till 16th century, was traced.

Author(s):  
L.E. Murr ◽  
V. Annamalai

Georgius Agricola in 1556 in his classical book, “De Re Metallica”, mentioned a strange water drawn from a mine shaft near Schmölnitz in Hungary that eroded iron and turned it into copper. This precipitation (or cementation) of copper on iron was employed as a commercial technique for producing copper at the Rio Tinto Mines in Spain in the 16th Century, and it continues today to account for as much as 15 percent of the copper produced by several U.S. copper companies.In addition to the Cu/Fe system, many other similar heterogeneous, electrochemical reactions can occur where ions from solution are reduced to metal on a more electropositive metal surface. In the case of copper precipitation from solution, aluminum is also an interesting system because of economic, environmental (ecological) and energy considerations. In studies of copper cementation on aluminum as an alternative to the historical Cu/Fe system, it was noticed that the two systems (Cu/Fe and Cu/Al) were kinetically very different, and that this difference was due in large part to differences in the structure of the residual, cement-copper deposit.


2021 ◽  
Author(s):  
Manuela Oliverio ◽  
Monica Nardi ◽  
Maria Luisa Di Gioia ◽  
Paola Costanzo ◽  
Sonia Bonacci ◽  
...  

Semi-synthesis is an effective strategy to obtain both natural and synthetic analogues of the olive secoiridoids, starting from easy accessible natural compounds.


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