The large number of isolated towers scattered in different spots of the hill on which the Dacian fortress at Blidaru was built intrigued the archaeologists right from the beginning of the excavations. In recent campaigns 4 of the 17 towers known until today were tested and some interesting construction details were observed. This paper presents an overview of the main results, a second one is meant to be soon published, dealing with the archaeology and history of the Blidaru fortress in the light of recent excavations. This first part comprises only a short presentation of the fortress itself, of the cisterns and of the temples found there during the excavations.
CRYSTALLOGRAPHY IN MATERIAL SCIENCE C389ammonium ions, size and precipitation speed of the globules.In fact, at high pH values we have spherical silica particles surrounded by a dense shell of gegenions that results in their electrostatic repulsion. As a result, during precipitating of particles on the surface of a supramolecular crystal, their position in the structure is conditioned by the repulsion of precipitating particles from the surface analogous to charged globules in the structure. It results in maximal filling of space. The situation is changed at low pH values and low sizes (less 400 nm) of particles which results in reducing their surface and the greater reduction of the concentration of gegenions, and as a consequence, of the force of their electrostatic repulsion. Forming here hydrogen bonds prevent the precipitation of the particles in the most favorable positions which results in reducing the filling ratio of the particles.In the framework of the experiment conducted by us, the packing type of spheric particles in opal matrixes depends on the sol pH and silica sphere sizes. At pH 7.5-8.0 a primitive cubic packing of particles is realized. The increase of pH up to 8.5-9.0 results in the formation of hexagonal packing with a corresponding increase of particle sizes. We analyzed amorphous and nanocrystalline natural and synthetic ferric oxides by X-ray diffraction (XRD), Mossbauer and UV-Vis spectroscopies, voltammetry of microparticles, and thermoanalytical methods. The quantitative analytical methods were tested with intermediates of the thermal conversion of ferrihydrite to nanocrystalline hematite.The XRD measurement with the addition of a known amount of reference material (Si) is not applicable when the mean coherence is only a few nm. Moessbauer spectroscopy and voltammetry of microparticles of such poorly ordered solids should be supported by the results of other methods, but under optimal conditions they are expected to "see" both amorphous and crystalline components with a comparable sensitivity permitting their determination. However, the minimal particle size of the target compounds is not known for Mossbauer spectroscopy and voltammetry of microparticles, and it seems to be equal or even larger than mean coherence length enabling XRD measurement. Diffuse reflectance spectroscopy can only be used to qualitative analysis, because the spectra of ferrihydrite and almost amorphous Fe 2 O 3 are hardly interpretable.The results indicate a lack of the knowledge on a local structure of 2-line ferrihydrite and XRD amorphous ferric oxides. Keywords: amorphous materials, nanocrystalline materials, iron oxides P.11.05.4 Acta Cryst. (2005). A61, C389 Revisitation of the Structural Models for FerrihydritesGabriele Navarra, Maria F. Casula, Gabriella Pinna, Department of Chemical Sciences, University of Cagliari, Cagliari, Italy. E-mail: navarra@unica.it Ferrihydrite is a generic term for various poorly ordered Fe(III) oxyhydroxides. They are also characterized by small particle size, as evident from ...
The archaeological site of “Măgura Uroiului” (Hunedoara County) is one of the most complex sites in Romania due to its geomorphologic qualities and continuously habitation from prehistory through the Middle Ages. It is a hill with volcanic origin and a series of natural platforms. It was a favorable place both for military fortifications, for civil settlements, and also for quarrying stone. In 2008 a wide-landscape archaeology study was started that includes a detailed digital cartography of the terrain and a 3D reconstruction of the whole archaeological complex and a paleomorphology study. Integrated remote sensing methods (satellite images analysis and geophysical prospects) were used. The first step was a detailed topographical measurement of the site’s surface with the help of a total station (over 100 hectares) in order to reveal all micro-relief details, both natural and manmade. The second step was the editing of GIS spatial data, 2D and 3D graphic reconstructions. The third step was the analysis of the geomorphologic evolution of the terrain, the identification and interpretation of man-made features, the recognition of the ways of human intervention in the environment and of the causes and effects generated in the local ecosystem. The fourth step was a interdisciplinary analysis combining remote sensing and geophysical prospects in order to establish the exact inhabited areas, fortification system, road network, etc. Our study is meant to be a multidisciplinary analysis and aims to establish the relationship between man and environment, the difficult part being the extraordinary complexity of this site and its dimensions.
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