Ultrasonic testing of laboratory samples representing monopile wind turbine foundations

Wind energy turbines and offshore hydrocarbon platforms rely on injected concrete grout to support and transfer loads between steel substructures. Deterioration of this grout under large operational stresses can lead to a loss of bonding, the formation of gaps, crushing and the loss of grout from the annulus between the steel substructures. In this paper, the integrity of the grout between two steel panels is experimentally tested using a low-frequency ultrasound backscatter method[1]. The experimental results and modelled outcomes[1] are compared for grout condition classes, including: good condition, gaps between the grout and either steel panel and the complete absence of grout. Pearson correlation coefficients of over 83% are observed when comparing the notch magnitudes and the frequencies on the modelled and experimental reflectance spectra of the front and rear gap, as well as missing grout conditions. Kolmogorov-Smirnov (K-S) similarity tests on the modelled and experimental notch magnitudes indicate a 20% significance on the rear gap and front gap spectra and a 10% significance on the missing grout spectra. The significance of these tests supports the potential application of backscattered low-frequency ultrasound for grout condition inspection. However, development of automated condition recognition algorithms, based on either spectral characteristics or time-localised spectral features of the backscatter, is required to make routine inspection commercially viable

Are the magnetic fields of millisecond pulsars ~ 10^8 G?

It is generally assumed that the magnetic fields of millisecond pulsars (MSPs) are $\sim 10^{8}$G. We argue that this may not be true and the fields may be appreciably greater. We present six evidences for this: (1) The $\sim 10^{8}$ G field estimate is based on magnetic dipole emission losses which is shown to be questionable; (2) The MSPs in low mass X-ray binaries (LMXBs) are claimed to have $< 10^{11}$ G on the basis of a Rayleygh-Taylor instability accretion argument. We show that the accretion argument is questionable and the upper limit $10^{11}$ G may be much higher; (3) Low magnetic field neutron stars have difficulty being produced in LMXBs; (4) MSPs may still be accreting indicating a much higher magnetic field; (5) The data that predict $\sim 10^{8}$ G for MSPs also predict ages on the order of, and greater than, ten billion years, which is much greater than normal pulsars. If the predicted ages are wrong, most likely the predicted $\sim 10^{8}$ G fields of MSPs are wrong; (6) When magnetic fields are measured directly with cyclotron lines in X-ray binaries, fields $\gg 10^{8}$ G are indicated. Other scenarios should be investigated. One such scenario is the following. Over 85% of MSPs are confirmed members of a binary. It is possible that all MSPs are in large separation binaries having magnetic fields $> 10^{8}$ G with their magnetic dipole emission being balanced by low level accretion from their companions.Comment: 16 pages, accept for publication in Astrophysics and Space Scienc

Study of two dose regimens of ticagrelor compared with clopidogrel in patients undergoing percutaneous coronary intervention for stable coronary artery disease

Background—Ticagrelor has superior efficacy to clopidogrel in the management of acute coronary syndromes but has not been assessed in patients undergoing percutaneous coronary intervention (PCI) for stable coronary artery disease (CAD). We compared the pharmacodynamic effects of ticagrelor and clopidogrel in this stable population. Methods—180 aspirin-treated stable CAD patients, who were planned to undergo elective PCI in a single center, were randomized 1:1:1 to either a standard clopidogrel regimen or one of two regimens of ticagrelor, either 90mg (T90) or 60mg twice-daily (T60), both with 180mg loading dose. Cellular adenosine uptake was assessed, at the time of the procedure and pre- and post-dose at 1 month, by adding adenosine 1 μmol/L to aliquots of anticoagulated whole blood and mixing with a stop solution at 0, 15, 30 and 60 seconds then measuring residual plasma adenosine concentration by high-performance liquid chromatography. Systemic plasma adenosine concentration and platelet reactivity were assessed at the same timepoints. High-sensitivity troponin T (hsTnT) was measured pre- and 18-24 hours post-PCI. Results—174 patients underwent an invasive procedure, of which 162 patients received PCI (mean age 65 years, 18% female, 21% with diabetes mellitus). No effect on in vitro adenosine uptake was seen post-dose at 1 month for either ticagrelor dose compared with clopidogrel (residual adenosine at 15s, mean ± SD: clopidogrel 0.274 ± 0.101 μmol/L; T90 0.278 ± 0.134 μmol/L; T60 0.288 ± 0.149 μmol/L; P = 0.37). Similarly no effect of ticagrelor on in vitro adenosine uptake was seen at other timepoints, nor was plasma adenosine concentration affected (all P > 0.1). Both maintenance doses of ticagrelor achieved more potent and consistent platelet inhibition than clopidogrel (VerifyNow PRU, 1 month, mean ± SD: pre-dose, T60: 62 ± 47, T90: 40 ± 38, clopidogrel 181 ± 44; post-dose, T60: 34 ± 30, T90: 24 ± 21, clopidogrel 159 ± 57; all P 208, 1-month post-dose: 0%, 0% and 21%, respectively). Median (IQR) hsTnT increase was 16.9 (6.5-46.9) ng/l for clopidogrel, 22.4 (5.5-53.8) ng/L for T60 and 17.7 (8.1-43.5) ng/L for T90 (P = 0.95). There was a trend towards less dyspnea with T60 versus T90 (7.1% vs 19.0%; P = 0.09). Conclusions—Maintenance therapy with T60 or T90 had no detectable effect on cellular adenosine uptake at 1 month, nor was there any effect on systemic plasma adenosine levels. Both regimens of ticagrelor achieved greater and more consistent platelet inhibition than clopidogrel but did not appear to affect troponin release after percutaneous coronary interventio

Magnetic Field Generation in Stars

Enormous progress has been made on observing stellar magnetism in stars from the main sequence through to compact objects. Recent data have thrown into sharper relief the vexed question of the origin of stellar magnetic fields, which remains one of the main unanswered questions in astrophysics. In this chapter we review recent work in this area of research. In particular, we look at the fossil field hypothesis which links magnetism in compact stars to magnetism in main sequence and pre-main sequence stars and we consider why its feasibility has now been questioned particularly in the context of highly magnetic white dwarfs. We also review the fossil versus dynamo debate in the context of neutron stars and the roles played by key physical processes such as buoyancy, helicity, and superfluid turbulence,in the generation and stability of neutron star fields. Independent information on the internal magnetic field of neutron stars will come from future gravitational wave detections. Thus we maybe at the dawn of a new era of exciting discoveries in compact star magnetism driven by the opening of a new, non-electromagnetic observational window. We also review recent advances in the theory and computation of magnetohydrodynamic turbulence as it applies to stellar magnetism and dynamo theory. These advances offer insight into the action of stellar dynamos as well as processes whichcontrol the diffusive magnetic flux transport in stars.Comment: 41 pages, 7 figures. Invited review chapter on on magnetic field generation in stars to appear in Space Science Reviews, Springe

Cosmology and Cosmogony in a Cyclic Universe

In this paper we discuss the properties of the quasi-steady state cosmological model (QSSC) developed in 1993 in its role as a cyclic model of the universe driven by a negative energy scalar field. We discuss the origin of such a scalar field in the primary creation process first described by F. Hoyle and J. V. Narlikar forty years ago. It is shown that the creation processes which takes place in the nuclei of galaxies are closely linked to the high energy and explosive phenomena, which are commonly observed in galaxies at all redshifts. The cyclic nature of the universe provides a natural link between the places of origin of the microwave background radiation (arising in hydrogen burning in stars), and the origin of the lightest nuclei (H, D, He$^3$ and He$^4$). It also allows us to relate the large scale cyclic properties of the universe to events taking place in the nuclei of galaxies. Observational evidence shows that ejection of matter and energy from these centers in the form of compact objects, gas and relativistic particles is responsible for the population of quasi-stellar objects (QSOs) and gamma-ray burst sources in the universe. In the later parts of the paper we briefly discuss the major unsolved problems of this integrated cosmological and cosmogonical scheme. These are the understanding of the origin of the intrinsic redshifts, and the periodicities in the redshift distribution of the QSOs.Comment: 51 pages including 1 figur

Chiropractic Observation and Analysis Study (COAST): Providing an understanding of current chiropractic practice

Objectives: COAST (Chiropractic Observation and Analysis Study) aimed to describe the clinical practices of chiropractors in Victoria, Australia. Design: Cross-sectional study using the BEACH (Bettering the Evaluation and Care of Health) methods for general practice. Setting and participants: 180 chiropractors in active clinical practice in Victoria were randomly selected from the list of 1298 chiropractors registered on Chiropractors Registration Board of Victoria. Twenty-four chiropractors were ineligible, 72 agreed to participate, and 52 completed the study. Main outcome measures: Each participating chiropractor documented encounters with up to 100 consecutive patients. For each chiropractor–patient encounter, information collected included patient health profile, patient reasons for encounter, problems and diagnoses, and chiropractic care. Results: Data were collected on 4464 chiropractor–patient encounters from 52 chiropractors between 11 December 2010 and 28 September 2012. In most (71%) encounters, patients were aged 25–64 years; 1% of encounters were with infants (age < 1 year; 95% CI, 0.3%–3.2%). Musculoskeletal reasons for encounter were described by patients at a rate of 60 per 100 encounters (95% CI, 54–67 encounters) and maintenance and wellness or check-up reasons were described at a rate of 39 per 100 encounters (95% CI, 33–47 encounters). Back problems were managed at a rate of 62 per 100 encounters (95% CI, 55–71 encounters). The most frequent care provided by the chiropractors was spinal manipulative therapy and massage. Conclusions: A range of conditions are managed by chiropractors in Victoria, Australia, but most commonly these conditions are musculoskeletal-related. These results can be used by stakeholders of the chiropractic profession in workforce development, education and health care policy

Assignment of the human alpha-tropomyosin gene TPM4 to band 19p13.1 by fluorescence in situ hybridization

Sequence-tagged sites (STSs) were developed for the human alpha-tropomyosin gene TPM4. One STS was used to amplify DNA from somatic cell hybrids to localize TPM4 to chromosome 19. The other, a product from a long-range PCR, was used directly as a probe to refine the localization of TPM4 to 19p13.1 by fluorescence in situ hybridization to metaphase chromosome spreads