64 research outputs found
Paleogene foraminifera of the Central and Southern North Sea, and their Biostratigraphical application
This thesis examines the Microfauna of the North Sea Palaeogene, particularly the foraminifera, and their biostratigraphical applications in the Central and Southern North Sea. A biostratigraphical scheme has been erected for calcareous benthic (CB Zones 1-15), agglutinated benthic (AB Zones 1-11b) and planktonic foraminifera (PK Zones la-13, utilising diatoms and radiolaria where necessary), which was then combined into one scheme using the previous 3 'groups'. The Shell Expro. U.K. computer was used to draw up rangecharts of these 'groups', and each well is described in the text and in 'Distribution charts' (See Enclosures Nos. 1-10, plus Rangecharts in pocket). The for amini feral biozonation of this thesis is correlated with NSP (North Sea planktonic) and NSB (North Sea benthonic) Zones of King (1983, 1989), the P Zones of Berggren et al. (1985), the sedimentological sequences of Stewart (1987) and the nannoplankton zones of L. Gallagher in his Ph.D. thesis. A canbined biostratigraphic scheme, utilising both foraminifera and nannoplankton was proposed in Gallaghers thesis and is discussed here
Potential effects of environmental change on mining wastes in a hyperarid climate
Three desert washes were sampled to evaluate the transport of contaminated sediments from abandoned mining sites to downwash environments. The area of concern is an extreme arid climate considered stable and not to pose pathways for contaminated sediments to impact downwash environments. Research of mine wastes in Nelson, Nevada has shown that residual geogenic and anthropogenic trace elements have been mobilized in surface sediments as a result of storm event. Cyanide and trace elements, especially mercury and lead, have transported to 6000 m downwash from source areas. Short term environmental impacts appear to be minimal because of present-day environmental conditions. However, climate shifts caused by the El Nino Southern Oscillations or even a dramatic climate shift might increase regional precipitation promoting a more rapid erosion of contaminated sediment. Currently, wash sediments do not contain levels of CN- or trace elements that pose threats to the environment; however, if erosion and transport of mining waste increased because of additional precipitation, then CN- and trace elements loading in storm water would increase, with their possibly delivery to Lake Mohave
Radon as an anthropogenic indoor air pollutant as exemplified by radium dial watches and other uranium- and radium- containing artefacts
Radon is generally regarded as a naturally occurring radiological hazard but we report here measurements of significant, hazardous radon concentrations that arise from man-made sources, e.g. radium-dial watches. This study is an examination and assessment of health risks from radium and uranium found in historical artefacts, and the radon that emanates from them. This includes radium-dial watches, the main focus, plus clocks, aircraft instruments, and ornaments and artefacts made of uranium glass / uranium-glazed. Such objects were very popular in the 1930s and 1940s and are still readily available today.
A collection of 30 radium-dial pocket and wrist watches was measured and shown to be capable of giving rise to radon concentrations two orders of magnitude greater than the UK Domestic Action Level of 200 Bq•m-3 in unventilated or poorly ventilated rooms. Furthermore, individual watches are capable of giving rise to radon concentrations in excess of the UK Domestic Action Level. We also highlight a gap in remediation protocols, which are focused on preventing radon entering buildings from outside, with regard to internally-generated radon hazards. Radon as arising from man-made objects such as radium-dial watches should be considered appropriately in radon protocols and guidelines
Radon emissions from radium-dial watches
Preliminary research during the latter half of 2011 has indicated that significant and potentially hazardous radon concentrations can arise from radium-dial watches stored in the built environment. Radium (226Ra) decays via alpha-particle emission to radon (222Rn); in addition, mesothorium (228Ra) and radiothorium (228Th) were also used in such watches and decay to thoron (220Rn). In the main experiments conducted to date, a set of radium-dial watches representative of a small private collection, was placed in a controlled access room, of volume 67 m3, that is continuously ventilated to the external environment. Prior to placing the watches in the room, the radon level at the maximum ventilation rate was ca. 10 Bq/m3. This rose to ca. 190-230 Bq/m3 following the placing of the watches in the room, again under conditions of maximum ventilation. When the ventilation rate decreased to a ‘standby’ setting, the radon concentration increased rapidly to ca. 2-3 kBq/m3, then decreased rapidly to the lower concentration when the ventilation rate returned to maximum. Extrapolation of results of monitoring a single watch under zero-ventilation conditions indicates that the zero-ventilation equilibrium concentration in the room arising from the set of watches exceeds 5 kBq/m3 and Monte-Carlo simulation indicates this could exceed 10 kBq/m3, both of which are greatly in excess of the UK Action Levels. Observation of such levels is largely unreported in the literature and our preliminary conclusion is that whilst collectors might be aware of the radiation hazard that arises directly from the radioactive material content of such watches, they are probably not aware of the large radon (and thoron) hazard that can arise, particularly if the watches are kept in a poorly ventilated room in a private house
Radon as a carcinogenic built-environmental pollutant
Radon (222Rn) has been highlighted by a number of authors as a significant public health concern. For example, it is the second most significant cause of lung cancer after tobacco smoking (ca. 1,000-2,000 and 21,000 deaths per year in the UK and USA respectively; US EPA, 2003; Darby et al., 2005; Dixon, 2006; HPA, 2009), yet a very high proportion of the general public appears to be unaware of the risk. This chapter deals with topical radon issues such as radon in the workplace; radon in homes; exposure to radon during leisure activities; radon and water; measurement and monitoring; seasonal correction; remediation; cancer risks; cost-benefit analysis and cost-effectiveness; mapping; future policies; and further research. This assessment of the state of radon research is focused on the UK as an example of a country where radon has been on the governmental agenda since the late 1970s, but also highlights radon issues throughout the world in, for example, the USA, Europe and Asia
Assessing low-maturity organic matter in shales using Raman spectroscopy : effects of sample preparation and operating procedure
Laser Raman spectroscopy is used to assess the thermal maturity of organic matter in sedimentary rocks, particularly organic-rich mudstones. However, discrepancies exist between quantified Raman spectral parameters and maturity values obtained by vitrinite reflectance. This has prevented the adoption of a standard protocol for the determination of thermal maturity of organic matter (OM) by Raman spectroscopy. We have examined the factors influencing the Raman spectra obtained from low-maturity OM in potential shale gas reservoir rocks. The inconsistencies in Raman results obtained are due to three main factors that are critically evaluated: (1) different operational procedures, including experiment setup and spectral processing methods; (2) different methods of sample preparation; (3) the analysis of diverse types of OM. These factors are scrutinized to determine the sources of inconsistency and potential bias in Raman results, and guidance is offered on the development of robust and reproducible analytical protocols. We present two new Raman parameters for un-deconvolved spectra named the DA1/GA ratio (area ratio of 1100–1400 cm−1/1550–1650 cm−1) and SSA (scaled spectrum area: sum of total area between 1100 and 1700 cm−1) that offer potential maturity proxies. An automated spreadsheet procedure is presented that processes raw Raman spectra and calculates several of the most commonly used Raman parameters, including the two new variables
Effects of etching time on alpha tracks in solid state nuclear track detectors
Solid State Nuclear Track Detectors (SSNTDs) are used extensively for monitoring alpha particle radiation, neutron flux and cosmic ray radiation. Radon gas inhalation is regarded as being a significant contributory factor to lung cancer deaths in the UK each year. Gas concentrations are often monitored using CR39 based SSNTDs as the natural decay of radon results in alpha particles which form tracks in these detectors. Such tracks are normally etched for about 4 hours to enable microscopic analysis. This study examined the effect of etching time on the appearance of alpha tracks in SSNTDs by collecting 2D and 3D image datasets using laser confocal imaging techniques. Etching times of 2 to 4 hours were compared and marked differences were noted in resultant track area. The median equivalent diameters of tracks were 20.2, 30.2 and 38.9 µm for etching at 2, 3 and 4 hours respectively. Our results indicate that modern microscope imaging can detect and image the smaller size tracks seen for example at 3 hours etching time. Shorter etching times may give rise to fewer coalescing tracks although there is a balance to consider as smaller track sizes may be more difficult to image. Thus etching for periods of less than 4 hours clearly merits further investigation as this approach has the potential to improve accuracy in assessing the number of tracks
Characterising radon emanations from radium-dial watches
Research during the latter half of 2011 has indicated that in addition to the hazard arising from the radium content of radium-dial watches, significant radon concentrations that exceed the UK Domestic and Workplace Action Levels of 200 Bq/m3 and 400 Bq/m3, respectively, can arise from watches stored in the built environment (1). In an extension to that earlier research, the radon emanations from the watches are being investigated in order to evaluate the radon hazard and the effective radium content of the watches. These radon measurements are made by placing the watches in a sealed chamber in a closed loop with a Durridge RAD7. We report here preliminary results from this ongoing investigation which suggest that radon emanation is not necessarily a straightforward function of radium content, as anticipated, but also depends on chamber temperature and humidity impacting upon watch-dependent factors such as design, construction, materials and wear-and-tear. Reference. 1. Gillmore G K, Crockett R G M, Denman A R, Flowers A, Harris R; Radium dial watches, a potentially hazardous legacy? Environment International. 45, 91–98. 2012. doi:10.1016/j.envint.2012.03.013
Full-scale fatigue testing of a wind turbine blade in flapwise direction and examining the effect of crack propagation on the blade performance
In this paper, the sensitivity of the structural integrity of wind turbine blades to debonding of the shear web from the spar cap was investigated. In this regard, modal analysis, static and fatigue testing were performed on a 45.7 m blade for three states of the blade: (i) as received blade (ii) when a crack of 200 mm was introduced between the web and the spar cap and (iii) when the crack was extended to 1000 mm. Calibration pull-tests for all three states of the blade were performed to obtain the strain-bending moment relationship of the blade according to the estimated target bending moment (BM) which the blade is expected to experience in its service life. The resultant data was used to apply appropriate load in the fatigue tests. The blade natural frequencies in flapwise and edgewise directions over a range of frequency domain were found by modal testing for all three states of the blade. The blade first natural frequency for each state was used for the flapwise fatigue tests. These were performed in accordance with technical specification IEC TS 61400-23. The fatigue results showed that, for a 200 mm crack between the web and spar cap at 9 m from the blade root, the crack did not propagate at 50% of the target BM up to 62,110 cycles. However, when the load was increased to 70% of target BM, some damages were detected on the pressure side of the blade. When the 200 mm crack was extended to 1000 mm, the crack began to propagate when the applied load exceeded 100% of target BM and the blade experienced delaminations, adhesive joint failure, compression failure and sandwich core failure
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