Lead artifacts

Fig. 6.2 Cross section of a corroded lead artifact before reduction (left) the different regions are (1) the porous corrosion patch, (2) some metal veins, (3) the metal core and (4) the electrolyte. Time-elapsed optical images (a-h) of the same section (right) during the reduction of the corrosion layer (from [303])...

Degrigny C (1995) Stabilisation de moteurs d avion immerges. Stud Conserv 40 10-18. Organ RM (1967) The reclamation of the wholly mineralized silver in the Ur lyre. In Application of Science to Examination of Works of Art, Museum of Fine Arts, Boston, 126-144. Degrigny C, Le GaU R (1999) Conservation of ancient lead artifacts corroded in organic acid environments electrolytic stabilization/consolidation. Stud Conserv 44 157-169. 

A.D. were found in old mines, and sizable slag deposits suggest at least some level of lead exploitation during Roman times (2). By the careful selection of Roman lead artifacts likely to have been manufactured in Carthage, and the use of lead isotope analysis, it may be possible to confirm the use of Tunisian lead ores during the Roman period. In this preliminary study, analysis of 22 curse tablets by electron microprobe analysis (EMPA) and six tablets by thermal ionization mass spectrometry (TIMS) suggest that these artifacts might be used to better understand Roman lead use and trade. 

On the other hand, the sensitivity of STM to electronic structure can lead to undesired artifacts when the surface is composed of regions of varying conductivity. For example, an area of lower conductivity will be represented as a dip in the image. If the surface is not well known, separating topographic effects from electronic effects can be difficult. 

The act of manipulating numbers on calculators of finite accuracy leads to numerical artifacts. (See Table l.l.) - ... 

The pulse duration controls the extent to which the magnetization vectors are bent. A misalignment of the pulse would lead to various artifact signals. Including 180° spin-echo pulses can, to some extent, compensate for setting pulses incorrectly. But in certain experiments (e.g., inverse NMR experiments), it is extremely important for the success of the experiment that the proper pulse angles be determined and employed. 

Accurate calibration of pulse lengths is essential for the success of most 2D NMR experiments. Wide variations (>20%) in the setting of pulse lengths may significantly reduce sensitivity and may lead to the appearance of artifact signals. In some experiments, such as inverse NMR experiments, accurately set pulse lengths are even more critical for successful outcomes. 

In certain areas, particularly the rapidly developing area of organo-metalhc spedation, concern has been expressed that artifacts may lead to false results. One example are the doubts about the accuracy and suspicion of possible artifact formation of methyhner-cury (MeHg) duriri analytical procedures, mainly distillation and alkaline dissolution, which were expressed for the first time at the Conference Mercury as a Global Pollu-tanf in 1996 (Hintelmann and Evans 1997 Hintelmann et al.1997). 

In his latest dig, Dr. Butrell found an abundance of lead (Pb) in some ancient artifacts. What is the atomic number of Pb ... 

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