Ductility normalized-strainrange partitioning life relations for creep-fatigue life predictions

Procedures based on Strainrange Partitioning (SRP) are presented for estimating the effects of environment and other influences on the high temperature, low cycle, creep fatigue resistance of alloys. It is proposed that the plastic and creep, ductilities determined from conventional tensile and creep rupture tests conducted in the environment of interest be used in a set of ductility normalized equations for making a first order approximation of the four SRP inelastic strainrange life relations. Different levels of sophistication in the application of the procedures are presented by means of illustrative examples with several high temperature alloys. Predictions of cyclic lives generally agree with observed lives within factors of three

Isothermal life prediction of composite lamina using a damage mechanics approach

A method for predicting isothermal plastic fatigue life of a composite lamina is presented in which both fibers and matrix are isotropic materials. In general, the fatigue resistances of the matrix, fibers, and interfacial material must be known in order to predict composite fatigue life. Composite fatigue life is predicted using only the matrix fatigue resistance due to inelasticity micromechanisms. The effect of the fiber orientation on loading direction is accounted for while predicting composite life. The application is currently limited to isothermal cases where the internal thermal stresses that might arise from thermal strain mismatch between fibers and matrix are negligible. The theory is formulated to predict the fatigue life of a composite lamina under either load or strain control. It is applied currently to predict the life of tungsten-copper composite lamina at 260 C under tension-tension load control. The calculated life of the lamina is in good agreement with available composite low cycle fatigue data

Evaluation of structural analysis methods for life prediction

The utility of advanced constitutive models and structural analysis methods are evaluated for predicting the cyclic life of an air-cooled turbine blade for a gas turbine aircraft engine. Structural analysis methods of various levels of sophistication were exercised to obtain the cyclic stress-strain response at the critical airfoil location. Calculated strain ranges and mean stresses from the stress-strain cycles were used to predict crack initiation lives by using the total strain version of the strain range partitioning life prediction method. The major results are given and discussed

Preliminary study of thermomechanical fatigue of polycrystalline MAR-M 200

Thermomechanical fatigue (TMF) experiments were conducted on polycrystalline MAR-M 200 over a cyclic temperature range of 500 to 1000 C. Inelastic strain ranges of 0.03 to 0.2 percent were imposed on the specimens. The TMF lives were found to be significantly shorter than isothermal low-cycle-fatigue (LCF) life at the maximum cycle temperature, and in-phase cycling was more damaging than out-of-phase cycling. Extensive crack tip oxidation appeared to play a role in promoting the severity of in-phase cycling. Carbide particle - matrix interface cracking was also observed after in-phase TMF cycling. The applicability of various life prediction models to the TMF results obtained was assessed. It was concluded that current life prediction models based on isothermal data as input must be modified to be applicable to the TMF results

Beyond-brand effect of television food advertisements on food choice in children: The effects of weight status

Copyright © The Authors 2007.Objective - To investigate the effect of television food advertising on children’s food intake, specifically whether childhood obesity is related to a greater susceptibility to food promotion. Design - The study was a within-subject, counterbalanced design. The children were tested on two occasions separated by two weeks. One condition involved the children viewing food advertisements followed by a cartoon, in the other condition the children viewed non-food adverts followed by the same cartoon. Following the cartoon, their food intake and choice was assessed in a standard paradigm. Setting - The study was conducted in Liverpool, UK. Subjects - Fifty-nine children (32 male, 27 female) aged 9–11 years were recruited from a UK school to participate in the study. Thirty-three children were normal-weight (NW), 15 overweight (OW) and 11 obese (OB). Results - Exposure to food adverts produced substantial and significant increases in energy intake in all children (P < 0·001). The increase in intake was largest in the obese children (P = 0·04). All children increased their consumption of high-fat and/or sweet energy-dense snacks in response to the adverts (P < 0·001). In the food advert condition, total intake and the intake of these specific snack items correlated with the children’s modified age- and gender-specific body mass index score. Conclusions - These data suggest that obese and overweight children are indeed more responsive to food promotion, which specifically stimulates the intake of energy-dense snacks.University of Liverpoo

The new dynamics of work: a scoping study

The world of work is changing as processes of globalisation, digitisation, economic crisis, demographic and social change intersect to produce new forms of work, working and working lives. At the same time, enduring inequalities of gender, class, race and ethnicity, age and region continue to shape the patterning of work and employment as well as the experiences and relations of working lives. The ‘new dynamics of work’ must be understood as emergent and complex formations at the intersection of continuity and change.‘Work’ includes both employment and unemployment, paid and unpaid work, in and outside formal workplaces. In order to better understand and respond to its increasing complexities and dynamics, research and policy must take the broadest possible interpretation of work

Detection of an endangered mammalian species using environmental DNA analysis

Poster presented at The Mammal Society 63rd Spring Conference & AGM, 31st March-2nd April, 2017, Cambridge, UK

Environmental DNA analysis – detection of endangered and invader species in wildlife conservation

Poster presented at Human Identification Solutions (HIDS) 2016, 10th-11th May, 2016, Barcelona, Spain

Environmental DNA analysis – non-invasive detection of endangered species in aquatic and terrestrial environments

Poster presented at Human Identification Solutions (HIDS) 2017, 16th-17th May, 2017, Vienna, Austria