Development of an electrolysis system for tritium enrichment in superficial water samples.
Tritium present in the environment gradually decreased in the last decades and nowadays it has reached extremely low activity concentrations. The purpose of the present work is the implementation of a tritium enrichment system in water samples using electrolytic techniques and pure nickel and iron electrodes. In the present work a mean tritium enrichment factor of 13.0 +/- 3.2 was obtained. This result should allow to reach a minimum detectable activity of tritium in water samples of about 1 tritium unit (TU) or less. The present enrichment system necessitates further adjustments and improvements, such as a cooling system in order to reduce the tritium losses due to evaporation.
Natural tritium measurements : determination of the electrolytic enrichment factor of tritium
Abstract For the purpose of improving the accuracy and precision of tritium measurements in natural waters, this paper proposes a new method for the estimation of tritium concentration after electrolytic enrichment. The proposed method was based on the fact that there is a reliable correlation between the water electrolytic enrichment of deuterium and that of tritium. The constancy of the ratio, k, during the electrolysis, k = α(β − 1)/β(α − 1), was experimentally verified, where α and β are the separation factors of deuterium and tritium, respectively. The value of k depends only on the electrode materials and the type of cells. The value of k is far more constant than the values of βα and of log β/log α. When the value of k was experimentally measured beforehand, the initial concentration of sample water, (T/H)0, could be estimated by the formula (T/H)0 = (T/H)f[(D/H)f(D/H)0]−k, where (T/H)f and (D/H)f are the tritium and deuterium contents after the electrolysis, and (D/H)0 is the deuterium content before the electrolysis.
Geographic And Environmental Influence On Maya Settlement Patterns Of The Northwest Yucatan: An Explanation For The Sparsely Settled Western Cenote Zone
Most settlement pattern research and GIS analysis of the ancient Maya of the Northern Yucatan have focused on water availability in a dry landscape where cenotes are often the only water source. While water is of paramount importance, permanent settlement secondarily requires farmable soil, a resource often as precious as water in many parts of the Yucatan. The dynamics between these resources reveal areas of ideal settlement and more challenging landscapes for which the Maya developed strategies to overcome environmental conditions. A region of the southwest "Cenote Zone", however, appears to have presented the ancient Maya with insurmountably poor environmental conditions despite abundant water resources. The lack of dense population and stone architecture in this area emphasizes the lack of a simple correlation between cenotes and settlement. This thesis uses GIS analysis to identify and explore such problematic settlement areas to better understand the factors and complexities involved in the more successful settlements of neighboring regions. iv This work is dedicated to my late father, who first introduced me to the Mundo Maya through a visit to the ruins of Tikal at the age of nine, and who instilled in me strength, curiosity, and a love for exploring the world. v ACKLOWLEDGEMENTS I'd like to acknowledge Dr. Arlen Chase and Dr. Diane Chase for providing such outstanding opportunities and instruction, and for leading by example both in the field and in the classroom. Dr. John Walker for his eye-opening perspectives, GIS instruction, inspiring hard-working attitude, and patience in the field. Dr. Clifford Brown and Dr. Walter Witschey for their invaluable correspondence and for their contributions to mapping and GIS data of Maya sites.