14C dating of small archaeological samples: neolithic to iron age in the central alpine region

Accelerator mass spectrometry (AMS) radiocarbon ¹⁴C dating will widen enormously the range and scope of archaeological investigations. This is due mainly to 100- to 1000-fold sample size reduction over conventional dating. In order to determine the size and the quality of samples that can be accepted for AMS ¹⁴C dating, we have selected archaeological samples relating to the Neolithic to Iron Age. The basis of our AMS target preparations is the coking (pyrolysis) of organic matter after elimination of impurities by various physical and chemical treatments. The effect of the morphology as well as of the grain size distribution of the charcoal particles was determined in order to achieve optimal conditions for accelerator dating.     

Evaluation of elemental status of ancient human bone samples from Northeastern Hungary dated to the 10th century AD by XRF

The present study is a multielemental analysis of bone samples belonging to skeletal individuals originating from two contemporaneous (10th century AD) cemeteries (Tiszavasvári Nagy-Gyepáros and Nagycserkesz-Nádasibokor sites) in Northeastern Hungary, using the XRF analytical technique. Emitted X-rays were detected in order to determine the elemental composition of bones and to appreciate the possible influence of the burial environment on the elemental content of the human skeletal remains. Lumbar vertebral bodies were used for analysis. Applying the ED(P)XRF technique concentration of the following elements were determined: P, Ca, K, Na, Mg, Al, Cl, Mn, Fe, Zn, Br and Sr. The results indicated post mortem mineral exchange between the burial environment (soil) and bones (e.g. the enhanced levels of Fe and Mn) and referred to diagenetic alteration processes during burials. However, other elements such as Zn, Sr and Br seemed to be accumulated during the past life. On the basis of statistical analysis, clear separation could not be observed between the two excavation sites in their bone elemental concentrations which denoted similar diagenetic influences, environmental conditions. The enhanced levels of Sr might be connected with the past dietary habits, especially consumption of plant food.     

Separation of W from Ta, Hf, Lu and Mo by BPHAC_5H_(11)OH/HCl extraction system (Model experiments for chemical study of seaborgium, the 106th element)

1 INTRODUCTIONIn the past years, the study of chemical property of transactinide elements gaineda broad interest from both experimental and theoretical chefests to determine theirpositions in the element periodic tabl.[1-4J. However, due to the "relativistic effect" oftransactinide elements, the deviation from regulaxity of the periodic table was not suitablefor .the transactinide elements compared with their lighter homologue elements. A fewOf modelling experiments aimed at studying the …     

The optimal column number for the improvement in heavy water removal rate from water-isotopes mixture by thermal diffusion in the countercurrent-flow Frazier scheme with the total sum of column heights fixed

The effect of column number on the enrichment of heavy water from water-isotope mixture in the countercurrent-flow Frazier scheme with total sum of column heights L fixed, has been investigated. The equations, which may be employed to predict the optimal column numbers for maximum performances, have been derived. Considerable improvement in removal rate is obtainable if the scheme is constructed with the optimal column number of thermal diffusion columns, especially for larger flow rate with smaller L, or smaller flow rate with larger L.     

The best column number in the countercurrent-flow Frazier scheme for deuterium recovery from water-isotopes mixture by thermal diffusion with total sum of column height fixed

The effect of column number on thermal diffusion in the countercurrent-flow Frazier scheme with total sum of column heights (L = Nh) fixed, has been investigated. The equations, which may be employed to predict the proper column number for the best performance are derived. Considerable improvement in performance is obtainable if the scheme is constructed with the proper number of thermal diffusion columns, instead of using a single column with column height L (N = 1, h = L). This is because that increasing the column height in a thermal diffusion column though increases the effective separation section, the increment in performance with the increase of column height will decrease, and finally the separation efficiency reaches a limiting value.