Dissolution of salts crystallised in building materials using ultrasound: an alternative to NORMAL (1983) standard methodology.
Our aim in the present work is to extract salts from ornamental stone using a faster and less tedious method than the customarily used NORMAL method [NORMAL, Dosaggio dei Sali Solubili, CNR-ICR, Roma, Italy (1983) 13/83]. For extraction in aqueous medium, the latter method requires shaking for 72 h at a temperature of 60 degrees C. Our aim is to attempt to shorten this time to less than 1 h using ultrasound. The results of the present study indicate that there is a good correlation between the amount of salts extracted applying the method described in the NORMAL (1983) normative and the amounts extracted with the method proposed here, subjecting the material to ultrasound (50 KHz) for 45 min.
Weathering of the Villamayor arkosic sandstone used in buildings, under a continental semi-arid climate
Abstract The Villamayor Sandstone is an arkosic sandstone, the cementing material of which is principally composed of palygorskite, smectite and by small amounts of other clay minerals, and of oxides. This stone has been used as a building material since the Roman period in Salamanca (Spain). This city is located in the plains of Castilla at an altitude of 800 m, characterized by a continental semi-arid climate with a mean rainfall of 420 mm/year and 2679 sunshine hours per year on the average. A comparative study of fresh and weathered sandstones collected from different areas of the city shows, through X-ray diffraction, DTA, DTG, SEM and chemical analyses, the existence of two-well defined weathering types. The first occurs in well drained locations where humid conditions following rainfall do not last long. It is characterized by a small loss of the finest fractions, especially smectite, the breakage of palygorskite fibres covering the pores, and oxidation of the ferrous components that produces the characteristic golden colour. The second type, observed in zones with fairly constant humid conditions, is characterised by a high degree of surficial salt precipitation which provokes a high physical degradation as compared to the first type.
Analysis of the Ionospheric Effect for Time Offsets per GPS Code Measurements
This paper shows the analysis results of time offsets using P1, P2 and P3 code in GPS time transfer. The r2cggtts program has been used in GNSS Time Transfer and use the P3 ionosphere free combination of P1 and P2 code measurements. We modified the r2cggtts program in order to calculate and write all kinds of time offsets P3 as well as P1 and P2. The result of the modified r2cggtts program shows that time offsets using P1 and P2 are of wide distribution comparing to time offsets using P3. In order to Figure out the error factors for wide distributions of P1 and P2, we analyze and present the relation between the elevation angle and time offsets in this paper.