Application of the PISA design model to monopiles embedded in layered soils

The PISA design model is a procedure for the analysis of monopile foundations for offshore wind turbine applications. This design model has been previously calibrated for homogeneous soils; this paper extends the modelling approach to the analysis of monopiles installed at sites where the soil profile is layered. The paper describes a computational study on monopiles embedded in layered soil configurations comprising selected combinations of soft and stiff clay and sand at a range of relative densities. The study comprises (a) analyses of monopile behaviour using detailed three-dimensional (3D) finite-element analysis, and (b) calculations employing the PISA design model. Results from the 3D analyses are used to explore the various influences that soil layering has on the performance of the monopile. The fidelity of the PISA design model is assessed by comparisons with data obtained from equivalent 3D finite-element analyses, demonstrating a good agreement in most cases. This comparative study demonstrates that the PISA design model can be applied successfully to layered soil configurations, except in certain cases involving combinations of very soft clay and very dense sand. </jats:p

PISA design methods for offshore wind turbine monopiles

Abstract This paper provides an overview of the PISA design model recently developed for laterally loaded offshore wind turbine monopiles through a major European joint-industry academic research project, the PISA Project. The focus was on large diameter, relatively rigid piles, with low length to diameter (L/D) ratios, embedded in clay soils of different strength characteristics, sand soils of different densities and in layered soils combining clays and sands. The resulting design model introduces new procedures for site specific calibration of soil reaction curves that can be applied within a one-dimensional (1D), Winkler-type, computational model. This paper summarises the results and key conclusions from PISA, including design methods for (a) stiff glacial clay till (Cowden till), (b) brittle stiff plastic clay (London clay), (c) soft clay (Bothkennar clay), (d) sand of varying densities (Dunkirk), and, (e) layered profiles (combining soils from (a) to (d)). The results indicate that the homogeneous soil reaction curves applied appropriately for layered profiles in the 1D PISA design model provide a very good fit to the three-dimensional finite element (3D FE) calculations, particularly for profiles relevant to current European offshore wind farm sites. Only a small number of cases, involving soft clay, very dense sand and L/D = 2 monopiles, would appear to require more detailed and bespoke analysis.</jats:p

Benign breast disease, recent alcohol consumption, and risk of breast cancer: a nested case–control study

INTRODUCTION: Alcohol consumption is a well-established risk factor for breast cancer. Some studies have suggested that the risk of breast cancer associated with alcohol consumption is greater for women with a history of benign breast disease (BBD). We hypothesized that among women with biopsy-confirmed BBD, recent alcohol consumption would increase the risk of breast cancer in women with proliferative breast disease to a greater extent than in women with nonproliferative breast disease. METHODS: We conducted a nested case–control study in the Nurses' Health Study I and II. The cases (n = 282) were women diagnosed with incident breast cancer, with a prior biopsy-confirmed breast disease. The controls (n = 1,223) were participants with a previous BBD biopsy, but without a diagnosis of breast cancer. Pathologists reviewed benign breast biopsy slides in a blinded fashion and classified the BBD as nonproliferative, proliferative without atypia, or atypical hyperplasia, according to standard criteria. RESULTS: Women with nonproliferative breast disease consuming ≥ 15 g of alcohol per day had a nonsignificant 67% increased risk of breast cancer (odds ratio = 1.67; 95% confidence interval 0.65 to 4.34) compared with nondrinkers. There was no evidence that recent alcohol consumption increased the risk of breast cancer to a greater extent in women with proliferative BBD than among women with nonproliferative BBD (P for interactio n = 0.20). CONCLUSION: Contrary to our a priori hypothesis, there was no evidence that recent alcohol consumption increased the risk of breast cancer to a greater extent among women with proliferative BBD than among women with nonproliferative BBD

α-glutathione s-transferase (α-GST) release, an early indicator of carbon tetrachloride hepatotoxicity in the rat

1. The use of the cytoplasmic enzyme, alpha glutathione s-transferase (alpha-GST) as an early index of carbon tetrachloride (CCl4) toxicity in the rat was investigated and compared with a standard enzyme, marker, aspartate aminotransferase (AST). The hepatotoxic effects of CCl4 in the rat were determined in a time and dose-response study. 2. Following CCl4 exposure, alpha-GST release was shown to be an earlier and more sensitive biomarker of hepatotoxicity than AST. 3. Significant increases in alpha-GST were detected 2 h after CCl4 exposure. Using the enzyme marker AST, this early hepatotoxic injury went undetected. At 6 and 16 h, alpha-GST was also a more sensitive indicator of hepatotoxicity than AST. 4. alpha-GST release was significantly increased at a dose of 5 microliters/kg, the lowest concentration of CCl4 administered and clearly responded in a dose-dependent manner with increasing doses of CCl4. In contrast, release of AST did not reach statistical significance until a dose of 25 microliters/kg. 5. Thus, these findings indicate that alpha-GST is a more sensitive and more accurate reflector of CCl4 induced hepatotoxicity than AST

How behavioural science can contribute to health partnerships: The case of The Change Exchange

© 2017 The Author(s). Background: Health partnerships often use health professional training to change practice with the aim of improving quality of care. Interventions to change practice can learn from behavioural science and focus not only on improving the competence and capability of health professionals but also their opportunity and motivation to make changes in practice. We describe a project that used behavioural scientist volunteers to enable health partnerships to understand and use the theories, techniques and assessments of behavioural science. Case studies: This paper outlines how The Change Exchange, a collective of volunteer behavioural scientists, worked with health partnerships to strengthen their projects by translating behavioural science in situ. We describe three case studies in which behavioural scientists, embedded in health partnerships in Uganda, Sierra Leone and Mozambique, explored the behaviour change techniques used by educators, supported knowledge and skill development in behaviour change, monitored the impact of projects on psychological determinants of behaviour and made recommendations for future project developments. Discussion: Challenges in the work included having time and space for behavioural science in already very busy health partnership schedules and the difficulties in using certain methods in other cultures. Future work could explore other modes of translation and further develop methods to make them more culturally applicable. Conclusion: Behavioural scientists could translate behavioural science which was understood and used by the health partnerships to strengthen their project work

Sensible heat has significantly affected the global hydrological cycle over the historical period

Globally, latent heating associated with a change in precipitation is balanced by changes to atmospheric radiative cooling and sensible heat fluxes. Both components can be altered by climate forcing mechanisms and through climate feedbacks, but the impacts of climate forcing and feedbacks on sensible heat fluxes have received much less attention. Here we show, using a range of climate modelling results, that changes in sensible heat are the dominant contributor to the present global-mean precipitation change since preindustrial time, because the radiative impact of forcings and feedbacks approximately compensate. The model results show a dissimilar influence on sensible heat and precipitation from various drivers of climate change. Due to its strong atmospheric absorption, black carbon is found to influence the sensible heat very differently compared to other aerosols and greenhouse gases. Our results indicate that this is likely caused by differences in the impact on the lower tropospheric stability