Electrical methods of geophysical survey are known to produce results that are hard to predict at different times of the year, and under differing weather conditions. This is a problem which can lead to misinterpretation of archaeological features under investigation. The dynamic relationship between a ‘natural’ soil matrix and an archaeological feature is a complex one, which greatly affects the success of the feature’s detection when using active electrical methods of geophysical survey. This study has monitored the gradual variation of measured resistivity over a selection of study areas. By targeting difficult to find, and often ‘missing’ electrical anomalies of known archaeological features, this study has increased the understanding of both the detection and interpretation capabilities of such geophysical surveys. A 16 month time-lapse study over 4 archaeological features has taken place to investigate the aforementioned detection problem across different soils and environments. In addition to the commonly used Twin-Probe earth resistance survey, electrical resistivity imaging (ERI) and quadrature electro-magnetic induction (EMI) were also utilised to explore the problem. Statistical analyses have provided a novel interpretation, which has yielded new insights into how the detection of archaeological features is influenced by the relationship between the target feature and the surrounding ‘natural’ soils. The study has highlighted both the complexity and previous misconceptions around the predictability of the electrical methods. The analysis has confirmed that each site provides an individual and nuanced situation, the variation clearly relating to the composition of the soils (particularly pore size) and the local weather history. The wide range of reasons behind survey success at each specific study site has been revealed. The outcomes have shown that a simplistic model of seasonality is not universally applicable to the electrical detection of archaeological features. This has led to the development of a method for quantifying survey success, enabling a deeper understanding of the unique way in which each site is affected by the interaction of local environmental and geological conditions.

Geophysical surveys in the Republic of Ireland and elsewhere rarely have the opportunity to receive direct, meaningful and quantitative feedback from ground observed excavations, despite their frequent occurrence as a subsequent phase of development-led archaeological projects. This research critically reappraises the largest and most coherent geophysical archive maintained by a single end-user over a ten year period. The geophysical archive has been collated from 170 reports on linear road schemes as a result of commercially-driven assessments in Ireland, to facilitate the biggest analysis of geophysical survey legacy data and subsequent detailed excavations. The analysis of the legacy data archive has reviewed and tested the influence of key variables that have, in some circumstances, affected the methods and outcomes of geophysical assessments in Ireland over the last 10 years. By understanding the impact of those key variables upon the legacy data - which include archaeological feature type, geology, sampling strategy and seasonality - appropriate and new ways to research linear corridors have been suggested that should be employed in future geophysical survey assessments for a range of environments and archaeological site types. The comprehensive analysis of geophysical surveys from the legacy data archive has created definitive statements regarding the validity of geophysical techniques in Ireland. Key failures that occurred in the past have been identified and a thorough investigation of new and novel techniques or methods of survey will facilitate a more robust approach to geophysical survey strategies in the future. The outcomes of this research are likely to have ramifications beyond the Irish road corridors from which the legacy data derives. / National Roads Authority (NRA)

Electrical methods of geophysical survey are known to produce results that are hard to predict at different times of the year, and under differing weather conditions. This is a problem which can lead to misinterpretation of archaeological features under investigation. The dynamic relationship between a ‘natural’ soil matrix and an archaeological feature is a complex one, which greatly affects the success of the feature’s detection when using active electrical methods of geophysical survey. This study has monitored the gradual variation of measured resistivity over a selection of study areas. By targeting difficult to find, and often ‘missing’ electrical anomalies of known archaeological features, this study has increased the understanding of both the detection and interpretation capabilities of such geophysical surveys. A 16 month time-lapse study over 4 archaeological features has taken place to investigate the aforementioned detection problem across different soils and environments. In addition to the commonly used Twin-Probe earth resistance survey, electrical resistivity imaging (ERI) and quadrature electro-magnetic induction (EMI) were also utilised to explore the problem. Statistical analyses have provided a novel interpretation, which has yielded new insights into how the detection of archaeological features is influenced by the relationship between the target feature and the surrounding ‘natural’ soils. The study has highlighted both the complexity and previous misconceptions around the predictability of the electrical methods. The analysis has confirmed that each site provides an individual and nuanced situation, the variation clearly relating to the composition of the soils (particularly pore size) and the local weather history. The wide range of reasons behind survey success at each specific study site has been revealed. The outcomes have shown that a simplistic model of seasonality is not universally applicable to the electrical detection of archaeological features. This has led to the development of a method for quantifying survey success, enabling a deeper understanding of the unique way in which each site is affected by the interaction of local environmental and geological conditions.

Geophysical surveys in the Republic of Ireland and elsewhere rarely have the opportunity to receive direct, meaningful and quantitative feedback from ground observed excavations, despite their frequent occurrence as a subsequent phase of development-led archaeological projects. This research critically reappraises the largest and most coherent geophysical archive maintained by a single end-user over a ten year period. The geophysical archive has been collated from 170 reports on linear road schemes as a result of commercially-driven assessments in Ireland, to facilitate the biggest analysis of geophysical survey legacy data and subsequent detailed excavations. The analysis of the legacy data archive has reviewed and tested the influence of key variables that have, in some circumstances, affected the methods and outcomes of geophysical assessments in Ireland over the last 10 years. By understanding the impact of those key variables upon the legacy data - which include archaeological feature type, geology, sampling strategy and seasonality - appropriate and new ways to research linear corridors have been suggested that should be employed in future geophysical survey assessments for a range of environments and archaeological site types. The comprehensive analysis of geophysical surveys from the legacy data archive has created definitive statements regarding the validity of geophysical techniques in Ireland. Key failures that occurred in the past have been identified and a thorough investigation of new and novel techniques or methods of survey will facilitate a more robust approach to geophysical survey strategies in the future. The outcomes of this research are likely to have ramifications beyond the Irish road corridors from which the legacy data derives.

Thesis (Ph.D.)--Baylor University, 2008. / Includes bibliographical references (p.109-118)

Electromagnetic induction (EM) methods have been utilised in a recent surge of archaeological applications across continental Europe, Ireland and Scandinavia. Development of multi-exploration depth instruments and improvements to instrument stability have improved its reputation as an effective method for mapping archaeological remains. Despite these advances, EM methods are comparatively lacking in rigour when for British sites. Through a structured scheme of experimental analysis and fieldwork, this thesis develops an understanding of the responses of EM instruments over a range of British archaeology, including earthworks, field systems, burials, modern remains, and a Cistercian abbey; the results of which demonstrate its effective over a diversity of environments. The impact of instrument-based issues on the collected measurements was quantified through a scheme of experiments targeting instrument drift, calibration and elevation. Dedicated instrument operation and processing workflows were developed based on the collective field and experimental results, which recommend best practice guidelines for improving the quality and accuracy of collected data. The link between instrument measurements and buried archaeology was further developed through a structured analysis of the EM datasets with complementary earth resistance and magnetic results. The integration of the EM, earth resistance and magnetic datasets was utilised to develop an enhanced archaeological characterisation of subsurface features. While the earth resistance and magnetic methods generally responded to different aspects of the buried archaeology, the EM surveys were able to detect a range of responses evident in the results of the former methods. Therefore, the role of EM methods within this characterisation are shown to “bridge the gap” between the earth resistance and magnetic methods, while providing a comprehensive characterisation of the remains in their own right.

Diploma thesis is oriented on measuring and evaluation of grounding conditions of HV pylons. In theoretical part is described theory of grounding including related legislation, impact of electric current on human body, methods of measuring earth resistance, soil resitivity and description of available measurers. Practical part is focused on measuring earth resistance of selected pylons and measuring procedures followed by evaluation of measurements according to person's safety from dangerous touch voltage and impact of lightings. For evauluation of measured data is created supporting tool in MS Excel. In the last part of thesis are described recommendations for cutting-down touch voltages.

Thesis: M.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1980 / Includes bibliographical references. / by Tarek Mohamed Habashy. / M.S. / M.S. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science

Thesis. 1975. Ph.D.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Sciences. / Vita. / Bibliography: leaves 158-162. / by David V. Fitterman. / Ph.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1980. / Microfiche copy available in Archives and Science. / Bibliography: leaves 67-74. / by Keiichiro Ikeda. / M.S.