Structural modelling and testing of failed high energy pipe runs: 2D and 3D pipe whip

Copyright @ 2011 ElsevierThe sudden rupture of a high energy piping system is a safety-related issue and has been the subject of extensive study and discussed in several industrial reports (e.g. [2], [3] and [4]). The dynamic plastic response of the deforming pipe segment under the blow-down force of the escaping liquid is termed pipe whip. Because of the potential damage that such an event could cause, various geometric and kinematic features of this phenomenon have been modelled from the point of view of dynamic structural plasticity. After a comprehensive summary of the behaviour of in-plane deformation of pipe runs [9] and [10] that deform in 2D in a plane, the more complicated case of 3D out-of-plane deformation is discussed. Both experimental studies and modelling using analytical and FE methods have been carried out and they show that, for a good estimate of the “hazard zone” when unconstrained pipe whip motion could occur, a large displacement analysis is essential. The classical, rigid plastic, small deflection analysis (e.g. see [2] and [8]), is valid for estimating the initial failure mechanisms, however it is insufficient for describing the details and consequences of large deflection behaviour

Effect of Glass Fiber Hybridization on the Behavior Under Impact of Woven Carbon Fiber/Epoxy Laminates

The low-velocity impact behavior was studied in hybrid laminates manufactured by RTM with woven carbon and glass (S2) fabrics. Specimens with different thicknesses and glass fiber content (from 0 to 21 vol.%) were tested with impact energies in the range 30–245 J and the resulting deformation and fracture micromechanisms were studied using X-ray microtomography. The results of these analyses, together with those of the impact tests (maximum load and energy absorbed), were used to elucidate the role played by glass fiber hybridization on the fracture micromechanisms and on the overall laminate performance under low-velocity impact

Effective elastic properties of randomly distributed void models for porous materials

This is the post-print version of the final paper published in International Journal of Mechanical Sciences. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2010 Elsevier B.V.Many 2D analytical models are available for estimating the effective elastic properties of porous materials. Most of these models adopt circular voids of a uniform diameter in superlattice arrays, such as unit void or periodically positioned models. There are two principal issues in a realistic representation of porous materials: the random distribution of a statistically sufficiently large number of voids in the model, and the random distribution of the size and position of the voids. Numerical schemes such as the FEM or the BEM have also been presented to cater for regular patterned circular voids. However, due to the large number of elements needed to produce sufficient accuracy for the curved boundary of circular voids or modelling a statistically sufficient number of voids with a random distribution in both the void size and the position, no such model has yet been produced. Modelling based on an FEM approach using a simplified approximation for void geometry is proposed here for the calculation of the effective elastic properties of porous solids. A plane strain model of a square geometry is adopted for a 2D array of voids. This simplified square shape allows a large number of voids to be simulated with a random distribution for both void sizes and their locations. The problem of anisotropy, which arises from the square shape, is discussed. It is verified that along the two principal directions (parallel to the sides of the square voids), the elastic properties remain the same as those predicted by using a circular void geometry. This square-shaped approximation, with its reduced requirement for FE analysis, has the potential to be extended to 3-dimensional modelling for a realistic simulation of engineering materials.University of Aberdee

Microplastics and synthetic particles ingested by deep-sea amphipods in six of the deepest marine ecosystems on Earth

Funding Funding for the laboratory work and analysis was from Newcastle University internal support. This work was supported by the 2007–2010 HADEEP project, funded by the Nippon Foundation (2009765188) and the Natural Environmental Research Council (NE/E007171/1). The 2011–2013 Kermadec Trench sampling was supported by the TOTAL Foundation (France) through the projects ‘Multi-disciplinary investigations of the deepest scavengers on Earth’ (2010–2012) and ‘Trench Connection’ (2013–2015). The Mariana samples were derived from the ‘FISH2017’ expedition (RV Shinyo-Maru SY1615) supported by the Tokyo University for Marine Science and Technology. Acknowledgements We thank the captain, crew and company of the research expeditions who assisted in the collection of the amphipods between 2008 and 2017, namely the Japanese Hakuho-Maru, Tansei Maru and Shinyo-Maru, the German Sonne and the RV Kaharoa in New Zealand. The assistance of David Whitaker and Peter McParlin from The School of Marine Science and Technology at Newcastle University are much appreciated. We are extremely grateful to Bob Keighley and Dan Parnaby at Shimadzu UK Limited for facilitating the FTIR analysis and access to their material database. We also thank Heather Stewart from the British Geological Survey for calculating the distances between trenches.Peer reviewedPublisher PD

Two temperature viscous accretion flows around rotating black holes: Description of under-fed systems to ultra-luminous X-ray sources

We discuss two temperature accretion disk flows around rotating black holes. As we know that to explain observed hard X-rays the choice of Keplerian angular momentum profile is not unique, we consider the sub-Keplerian regime of the disk. Without any strict knowledge of the magnetic field structure, we assume the cooling mechanism is dominated by bremsstrahlung process. We show that in a range of Shakura-Sunyaev viscosity parameter 0.2\gsim\alpha\gsim0.0005, flow behavior varies widely, particularly by means of the size of disk, efficiency of cooling and corresponding temperatures of ions and electrons. We also show that the disk around a rotating black hole is hotter compared to that around a Schwarzschild black hole, rendering a larger difference between ion and electron temperatures in the former case. With all the theoretical solutions in hand, finally we reproduce the observed luminosities ($L$) of two extreme cases -- the under-fed AGNs and quasars (e.g. Sgr $A^*$) with L\gsim 10^{33} erg/sec to ultra-luminous X-ray sources with $L\sim 10^{41}$ erg/sec, at different combinations of mass accretion rate, ratio of specific heats, Shakura-Sunyaev viscosity parameter and Kerr parameter, and conclude that Sgr $A^*$ may be an intermediate spinning black hole.Comment: 21 pages including 5 figures; few typos corrected; to appear in New Astronom

Associations between blood sex steroid concentrations and risk of major adverse cardiovascular events in healthy older women in Australia: a prospective cohort substudy of the ASPREE trial

Background: Blood testosterone concentrations in women decline during the reproductive years and reach a nadir in the seventh decade, after which concentrations increase and are restored to those of reproductive-aged women early in the eighth decade. We aimed to establish the association between the concentration of testosterone in the blood and risk of major adverse cardiovascular events (MACE) and all-cause mortality in healthy older women. Methods: SHOW was a prospective cohort substudy of the longitudinal randomised ASPREE trial. Eligible participants were women aged at least 70 years from Australia with unimpaired cognition, no previous MACE, and a life expectancy of at least 5 years. Participants who were receiving hormonal or steroid therapy were ineligible for inclusion. We measured serum concentrations of sex steroids with liquid chromatography–tandem mass spectrometry and of SHBG with immunoassay. We compared lower concentrations of sex hormones with higher concentrations using four quartiles. Primary endpoints were risk of MACE and all-cause mortality, the associations of which with sex steroid concentrations were assessed using Cox proportional hazards regression that included age, body-mass index, smoking status, alcohol consumption, diabetes, hypertension, dyslipidaemia, impaired renal function, and treatment allocation in the ASPREE trial (aspirin vs placebo). ASPREE is registered with ClinicalTrials.gov, NCT01038583. Findings: Of the 9180 women recruited to the ASPREE trial between March 10, 2010, and Dec 31 2014, 6358 participants provided sufficient biobank samples at baseline and 5535 were included in the final analysis. Median age at entry was 74·0 years (IQR 71·7–77·7). During a median 4·4 years of follow-up (24 553 person-years), 144 (2·6%) women had a first MACE (incidence 5·9 per 1000 person-years). During a median 4·6 years of follow-up (3·8–5·6), 200 women died (7·9 per 1000 person-years). In the fully adjusted models, higher concentrations of testosterone were associated with a lower incidence of MACE (quartile 4 vs quartile 1: hazard ratio 0·57 [95% CI 0·36–0·91]; p=0·02), as were higher concentrations of DHEA (quartile 4 vs quartile 1: 0·61 [0·38–0·97]; p=0·04). For oestrone, a lower risk of MACE was seen for concentrations in quartile 2 only, compared with quartile 1 (0·55 [0·33–0·92]; p=0·02). In fully adjusted models, no association was seen between SHBG and MACE, or between any hormone or SHBG and all-cause mortality. Interpretation: Blood concentrations of testosterone and DHEA above the lowest quartile in older women were associated with a reduced risk of a first-ever MACE. Given that the physiological effects of DHEA are mediated through its steroid metabolites, if the current findings were to be replicated, trials investigating testosterone therapy for the primary prevention of ischaemic cardiovascular disease events in older women would be warranted. Funding: The National Health and Medical Research Council of Australia, US National Institute on Aging, the Victorian Cancer Agency, the Commonwealth Scientific and Industrial Research Organisation, and Monash University

Neutrinos in Non-linear Structure Formation - The Effect on Halo Properties

We use N-body simulations to find the effect of neutrino masses on halo properties, and investigate how the density profiles of both the neutrino and the dark matter components change as a function of the neutrino mass. We compare our neutrino density profiles with results from the N-one-body method and find good agreement. We also show and explain why the Tremaine-Gunn bound for the neutrinos is not saturated. Finally we study how the halo mass function changes as a function of the neutrino mass and compare our results with the Sheth-Tormen semi-analytic formulae. Our results are important for surveys which aim at probing cosmological parameters using clusters, as well as future experiments aiming at measuring the cosmic neutrino background directly.Comment: 20 pages, 8 figure

Bell-inequality violation with "thermal" radiation

The model of a quantum-optical device for a conditional preparation of entangled states from input mixed states is presented. It is demonstrated that even thermal or pseudo-thermal radiation can be entangled in such a way, that Bell-inequalities are violated

Effect of mill type on the size reduction and phase transformation of gamma alumina

The influence of stress modes and comminution conditions on the effectiveness of particle size reduction of a common catalyst support; γ-Alumina is examined through a comparative assessment of three different mill types. Air jet milling is found to be the most effective in reducing particle size from a d90 of 37 µm to 2.9 µm compared to planetary ball milling (30.2 µm) and single ball milling (10.5 µm). XRD and TEM studies confirm that the planetary ball mill causes phase transformation to the less desired α-Alumina resulting in a notable decrease in surface area from 136.6 m2/g to 82.5 m2/g as measured by the BET method. This is consistent with the large shear stresses under high shear rates prevailing in the planetary ball mill when compared to the other mill types. These observations are consistent with a shear-induced phase transformation mechanism brought about by slip on alternate close packed oxygen layers from a cubic close packed to a hexagonal close packed structure

Determinants of the maternal 25-hydroxyvitamin D response to vitamin D supplementation during pregnancy

Context: Current approaches to antenatal vitamin D supplementation do not account for interindividual differences in 25-hydroxyvitamin D (25(OH)D) response.Objective: We assessed which maternal and environmental characteristics were associated with 25(OH)D after supplementation with cholecalciferol.Design: Within-randomization-group analysis of participants in the Maternal Vitamin D Osteoporosis Study trial of vitamin D supplementation in pregnancy.Setting: Hospital antenatal clinics.Participants: A total of 829 pregnant women (422 placebo, 407 cholecalciferol). At 14 and 34 weeks of gestation, maternal anthropometry, health, and lifestyle were assessed and 25(OH)D measured. Compliance was determined using pill counts at 19 and 34 weeks.Interventions: 1000 IU/d of cholecalciferol or matched placebo from 14 weeks of gestation until delivery.Main Outcome Measure: 25(OH)D at 34 weeks, measured in a single batch (Diasorin Liaison).Results: 25(OH)D at 34 weeks of gestation was higher in the women randomized to vitamin D (mean [SD], 67.7 [21.3] nmol/L) compared with placebo (43.1 [22.5] nmol/L; P &lt; .001). In women randomized to cholecalciferol, higher pregnancy weight gain from 14 to 34 weeks of gestation (kg) (? = ?0.81 [95% confidence interval ?1.39, ?0.22]), lower compliance with study medication (%) (? = ?0.28 [?0.072, ?0.48]), lower early pregnancy 25(OH)D (nmol/L) (? = 0.28 [0.16, 0.40]), and delivery in the winter vs the summer (? = ?10.5 [?6.4, ?14.6]) were independently associated with lower 25(OH)D at 34 weeks of gestation.Conclusions: Women who gained more weight during pregnancy had lower 25(OH)D in early pregnancy and delivered in winter achieved a lower 25(OH)D in late pregnancy when supplemented with 1000 IU/d cholecalciferol. Future studies should aim to determine appropriate doses to enable consistent repletion of 25(OH)D during pregnancy.<br/