Local and regional induction in the British Isles

Electric currents induced in the shallow seas and deep ocean around the British Isles have a profound effect upon the electromagnetic fields observed at stations on the land. The configuration of anomalous currents changes with frequency, and causes corresponding changes in the geomagnetic transfer functions. Magnetic variations have been recorded at a dense network of sites in southern Scotland and northern England. Single­ station transfer functions have been used to generate hypothetical event maps of the anomalous vertical field, and hence to infer the configuration of the anomalous internal currents. At periods exceeding 2000 s, the vertical field is dominated by the effects of electric currents to the west, presumably in the Atlantic Ocean . In the period range 400-2000 s, anomalous currents are concentrated in a thin sheet comprising the shallow seas, the t hick sequences of post-Caledonian sedimentary rock which underlie them, and the extensions of the sedimentary basins into the land. The response of the individual basin is determined not only by its local conductivity structure, but also by the extent of its connection to the shallow seas,i.e. its regional importance within the conductive sheet. At periods less than 200 s on the other hand, the anomalous fields at inland sites are principally determined by the local geological structure . These results confirm conclusions reached from theoretical studies of electromagnetic induction in a heterogeneous surface layer (Park, Orange & Madden); that electromagnetic response data measured in a 3-D environment such as the Northumberland Basin must be interpreted using 3-D models . If one or 2-D models are used, the data must be corrected on the basis of regional measurements

Melting in the crust and upper mantle beneath the Kenya Rift: evidence from Geomagnetic Deep Sounding experiments

A Geomagnetic Deep Sounding experiment in and around the Kenya Rift Valley has shown that telluric currents are concentrated by 3 regions with high electrical conductivity. Two of the anomalies are related to the rift structure, and the combination of different lines of geophysical evidence strongly suggests that the high conductivity is due to the presence of molten material in the rocks of the lower crust and upper mantle. The shallower zone where melt is present is located directly beneath the floor of the rift valley. Its upper surface is no deeper than 20 km; it may be as shallow as 5 km. The electrical conductivity is compatible with an average melt concentration of 5-10%, but could also be explained by discrete magma chambers where the concentration was much higher. The deeper conductor is located to the E of the rift valley beneath the Aberdare Mountains, and possibly extends beneath Mount Kenya. The Geomagnetic Deep Sounding data suggest a depth of 100 km to the high conductivity body, which appears to correspond to the core (the region with the highest melt concentration) of a zone of more diffuse melting in the mantle, that is responsible for seismic and regional gravity anomalies, and which supports a part of the topographic elevation of the Kenya dome

Geomagnetic variation anomalies in northern England: processing and presentation of data from a non-simultaneous array

The block and basin structure of northern England has been investigated by an array of 35 magnetometer stations over a grid with a spacing of 10km. Recordings at these sites were made simultaneously with those at a reference site. Using the common reference data, transfer function analysis enables the three anomalous field components to be estimated at each site, for the period range 10-10**4 s. Using the transfer functions obtained, maps of the anomalous field components may be generated across the array, and used for interpretation of electrical conductivity structure. Maps thus obtained from the non-simultaneous array data in northern England are used to illustrate the advantages of the method, and provide evidence of an east-west current flow concentrated along the southern margin of the Northumberland Trough. The limitations of the procedure, although slight, are considered. The errors which arise in the method are deduced and tech­niques for their removal are suggested

Re-austenitisation of thin ferrite films in C-Mn steels during thermal rebound at continuously cast slab corner surfaces

DATA AVAILABILITY STATEMENT : Data presented in this article is available at request from the corresponding author.The influence of primary cooling and rebound temperature at C–Mn slab corner surfaces during continuous casting on ferrite film transformation and AlN precipitation was investigated. Laboratory simulations included primary cooling to minimum temperature, Tmin, rebounding to various maximum temperatures, Tmax, followed by secondary cooling. The negative effect of a low Tmin on hot ductility could not be readily reversed, even at relatively high temperatures. Quantitative metallography was employed to study the evolution of the microstructure during rebounding and secondary cooling. Following primary cooling to temperatures just above the Ar3, thin films of allotriomorphic ferrite formed on the austenite grain boundaries. These films did not completely transform to austenite during the rebound at 3 C/s up to temperatures as high as 1130 C and persisted during slow secondary cooling up to the simulated straightening operation. Whilst dilatometry did not indicate the presence of ferrite after high rebound temperatures, metallography provided clear evidence of its existence, albeit in very small quantities. Coincident with the ferrite at these high temperatures was the predicted (TC-PRISMA) grain boundary precipitation of AlN in bcc iron during the rebound from a Tmin of 730 C. Importantly no thin ferrite films were observed, and AlN precipitation was not predicted to occur when Tmin was restricted to 830 C. Cooling below this temperature promotes austenite grain boundary ferrite films and AlN precipitation, which both increase the risk of corner cracking in C–Mn steels.https://www.mdpi.com/journal/metalsam2023Materials Science and Metallurgical Engineerin

Effect of intercritical annealing of normalised Nb-Ti-V microalloyed plate steel on microstructural evolution

A homogeneous microstructure is required for consistent mechanical properties in normalised Nb-Ti-V microalloyed plate steels. Frequently, as-hot rolled microalloyed plate steels have a banded microstructure that is persistent even after normalising heat treatment (NHT), and this leads to inconsistencies and some scatter in mechanical properties. Therefore, this work focused on the influence of single-cycle normalising heat treatment (SNHT), doublecycle normalising heat treatment (DNHT) followed by intercritical annealing normalising heat treatment (INHT) on the homogenisation and mitigation of a banded microstructure. The study was conducted on a 0.13C-Nb-Ti-V plate steel grade. The as-hot rolled microstructure was banded and had a 1.13 Anisotropy Index (AI) value. Results from the three thermal cycles revealed that the DNHT and INHT mitigated the pearlite microstructural banding and gave a more homogenized pearlite phase distribution throughout the microstructure, unlike the SNHT that retained the banding. The DNHT also exhibited the finest ferrite grain size, while the INHT exhibited the coarsest. From Vickers hardness measurements (153±5.8 HV, 157±3.6 HV and 166±4.5 HV), the UTS was approximately deduced as, 480, 490 and 530 MPa for the SNHT, DNHT and INHT respectively.http://iopscience.iop.org/journal/1757-899Xam2020Materials Science and Metallurgical Engineerin

(Non)commutative isotropization in Bianchi I with Barotropic perfect fluid and Λ\Lambda Cosmological

We present the classical solutions to the Einstein field equations derived using the WKB-like and Hamilton procedures. The investigation is carried out in the commutative and noncommutative scenario for the Bianchi type I cosmological model coupled to barotropic perfect fluid and $\lambda$ Cosmological for two different gauges. Noncommutativity is achieved by modifying the symplectic structure considering that all minisuperspace variables $\rm q^i$ does not commute and by a deformation between all the minisuperspace variables. In the gauge N=1, it is possible to obtain that the anisotropic parameter $\rm \beta_{\pm nc}$ tend to a constant curvature for large period of time considering different values in the noncommutative parameters $\theta$ and cosmological term. However, this behavior give the idea that is necessary introduce other class of matter in the models, for to have a real isotropization in the model, such as dark energy or dark matter.Comment: 15 pages, 1 figur

A lattice study of 3D compact QED at finite temperature

We study the deconfinement phase transition and monopole properties in the finite temperature 3D compact Abelian gauge model on the lattice. We predict the critical coupling as function of the lattice size in a simplified model to describe monopole binding. We demonstrate numerically that the monopoles are sensitive to the transition. In the deconfinement phase the monopoles appear in the form of a dilute gas of magnetic dipoles. In the confinement phase both monopole density and string tension differ from semiclassical estimates if monopole binding is neglected. However, the analysis of the monopole clusters shows that the relation between the string tension and the density of monopoles in charged clusters is in reasonable agreement with those predictions. We study the cluster structure of the vacuum in both phases of the model.Comment: 18 pages, 14 EPS figures, LaTeX uses epsfig.st

Effective Field Theory for Dilute Fermions with Pairing

Effective field theory (EFT) methods for a uniform system of fermions with short-range, natural interactions are extended to include pairing correlations, as part of a program to develop a systematic Kohn-Sham density functional theory (DFT) for medium and heavy nuclei. An effective action formalism for local composite operators leads to a free-energy functional that includes pairing by applying an inversion method order by order in the EFT expansion. A consistent renormalization scheme is demonstrated for the uniform system through next-to-leading order, which includes induced-interaction corrections to pairing.Comment: 31 pages, 10 figures, affiliation updated, paper unchange

Inter-rater reliability of the EPUAP pressure ulcer classification system using photographs

Background. Many classification systems for grading pressure ulcers are discussed in the literature. Correct identification and classification of a pressure ulcer is important for accurate reporting of the magnitude of the problem, and for timely prevention. The reliability of pressure ulcer classification systems has rarely been tested. Aims and objectives. The purpose of this paper is to examine the inter-rater reliability of classifying pressure ulcers according to the European Pressure Ulcer Advisory Panel classification system when using pressure ulcer photographs.Design. Survey was among pressure ulcer experts.Methods. Fifty-six photographs were presented to 44 pressure ulcer experts. The experts classified the lesions as normal skin, blanchable erythema, pressure ulcer (four grades) or incontinence lesion. Inter-rater reliability was calculated.Results. The multirater-Kappa for the entire group of experts was 0.80 (P < 0.001).Various groups of experts obtained comparable results. Differences in classifications are mainly limited to 1 degree of difference. Incontinence lesions are most often confused with grade 2 (blisters) and grade 3 pressure ulcers (superficial pressure ulcers).Conclusions. The inter-rater reliability of the European Pressure Ulcer Advisory Panel classification appears to be good for the assessment of photographs by experts. The difference between an incontinence lesion and a blister or a superficial pressure ulcer does not always seem clear.Relevance to clinical practice. The ability to determine correctly whether a lesion is a pressure ulcer lesion is important to assess the effectiveness of preventive measures. In addition, the ability to make a correct distinction between pressure ulcers and incontinence lesions is important as they require different preventive measures. A faulty classification leads to mistaken measures and negative results. Photographs can be used as a practice instrument to learn to discern pressure ulcers from incontinence lesions and to get to know the different grades of pressure ulcers. The Pressure Ulcer Classification software package has been developed to facilitate learning