Magnetic Pulse Welding for Dissimilar and Similar Materials

The Magnetic Pulse Welding (MPW) process, a cold solid state welding process, is an industrial process, operating at several high volume manufacturing facilities. MPW is accomplished by the magnetically driven, high velocity, oblique angle, impact of two metal surfaces. At impact, the surfaces (which will always have some level of oxidation) are stripped off and ejected by the closing angle of impact. The surfaces which are then metallurgically pure, are pressed into intimate contact by the magnetic pressure, allowing valence electron sharing and atomic-level bonding. This process has been demonstrated in the joining of tubular configurations of a variety of metals and alloys [1],[2],[3]. Product designers are frequently constrained by the restrictions of traditional joining technologies, which place certain limitations on the type of joint, the materials that can be joined and the quality of the joint. Solid state welding allows manufacturers to significantly improve their product designs and production results by enabling both dissimilar and similar materials to be welded together, thus providing the opportunity to use lighter and stronger material combinations. Magnetic pulse welding is a fast, noncontact and clean solid state welding process. A review of the main elements of the process is presented here along with typical quality testing results and some applications

Magnetic Pulse Acceleration

The present work is dedicated to describing works in the spheres of simulation, calculation, and experimental results of acceleration by pulsed electromagnetic forces where strain rates of 10,000 - 50,000 s^(-1) are common. The goal is to design a multidisciplinary model that will overcome the shortcomings of normal simulation methods that solve the EM field and then apply the solution in a mechanical analysis. Improved numeric models for virtual simulation of magnetic pulse processes are detailed, along with the pulse-power equipment and a special measurement system developed to verify these models and to determine material property data. These measure both radial velocity and axial speed (collision-point progression) for tube forming and / or welding processes, while logging the pulse current and magnetic field. The results show good a correlation between test and multiphysics model and provide valuable new insights, as well as an extraction of critical parameters by way of a comparison between calculated and measured data for materials such as aluminum alloys, copper, and steel

Pulsed Power Forming

R&D and application work in the sphere of Pulsed Power Forming (PPF) is well known and has been documented since the 1960's, along with its advantages. Pulsed Power Forming applications, which have been developed at Pulsar Ltd over the last decade, are described in this paper. Special equipment and tools for forming have been designed, developed, and manufactured, utilising pulsed magnetic fields. Theoretical and experimental research has been carried out to determine the magnetic field distribution in certain types of solenoids for diameters up to 600 mm. The software for mechanical pressure simulation and calculation has been carried out. Research and application of forming by electrical discharge into liquid medium have been carried out with higher deformation than it has been attained by the classic processes. Flat forming, cutting, and/or perforating of very thin materials (with thicknesses in the range of 0,1 up to 0,3 mm), such as aluminium, steel, stainless steel, nickel alloys, etc., have been made by applying high magnetic field with elastic medium. In addition, forming and cutting of a steel tube with ~100 mm OD and a wall thickness up to 3 mm have been executed using direct high pulse magnetic field action. Aluminium tubes with OD ~100 mm and a wall thickness less than 0,5 mm have also been similarly processed

Wilson's disease: update on pathogenesis, biomarkers and treatments

Wilson’s disease is an autosomal–recessive disorder of copper metabolism caused by mutations in ATP7B and associated with neurological, psychiatric, ophthalmological and hepatic manifestations. Decoppering treatments are used to prevent disease progression and reduce symptoms, but neurological outcomes remain mixed. In this article, we review the current understanding of pathogenesis, biomarkers and treatments for Wilson’s disease from the neurological perspective, with a focus on recent advances. The genetic and molecular mechanisms associated with ATP7B dysfunction have been well characterised, but despite extensive efforts to identify genotype–phenotype correlations, the reason why only some patients develop neurological or psychiatric features remains unclear. We discuss pathological processes through which copper accumulation leads to neurodegeneration, such as mitochondrial dysfunction, the role of brain iron metabolism and the broader concept of selective neuronal vulnerability in Wilson’s disease. Delayed diagnoses continue to be a major problem for patients with neurological presentations. We highlight limitations in our current approach to making a diagnosis and novel diagnostic biomarkers, including the potential for newborn screening programmes. We describe recent progress in developing imaging and wet (fluid) biomarkers for neurological involvement, including findings from quantitative MRI and other neuroimaging studies, and the development of a semiquantitative scoring system for assessing radiological severity. Finally, we cover the use of established and novel chelating agents, paradoxical neurological worsening, and progress developing targeted molecular and gene therapy for Wilson’s disease, before discussing future directions for translational research

3D Impacts Modeling of the Magnetic Pulse Welding Process and Comparison to Experimental Data

Magnetic Pulse Welding (MPW) is a solid state (cold) welding process known to present several advantages. When properly designed, such an assembly is stronger than the weakest base material even for multi-material joining. These high quality welds are due to an almost inexistent Heat Affected Zone which is not the case with fusion welding solutions. Another advantage is a welding time that is under a millisecond. In order to define the MPW parameters (mainly geometry, current and frequency), recent developments have made it possible to adapt welding windows from the Explosive Welding (EXW) for use in MPW. Until now, these welding windows have been simulated only in 2D geometries showing how the impact angle and the radial velocities progress in a welding window. The aim of this paper is to present our most recent development, which builds on this analysis to develop a 3D model in order to deal for example with local planar MPW. Simulation results will be presented and then compared to experimental data for a multimaterial join case

Liver transplantation for late-onset acute liver failure in Wilson’s disease: the UK experience over two decades

BACKGROUNDS AND AIMS: Acute liver failure as the initial presentation of Wilson’s disease is usually associated with onset in childhood, adolescence or early adulthood. Outcomes after transplantation for late-onset presentations, at or after 40 years, are seldom reported in the literature METHODS: We report a case, review the literature and provide unpublished data from the UK Transplant Registry on late-onset acute liver failure in Wilson’s disease. RESULTS: We describe a 62-year-old man presenting with acute liver failure who was successfully treated with urgent liver transplantation. We identified seven cases presenting at age 40 years or over in the literature where individual outcomes were reported; three were treated with transplantation and two survived. We identified a further eight cases listed for transplantation in the UK between 1995 and 2014; seven were treated with transplantation and six survived. One patient was de-listed for unknown reasons. CONCLUSIONS: We discuss the need to consider Wilson’s disease in older adults presenting with acute liver failure and importance of making the diagnosis prior to transplantation. We suggest that urgent liver transplantation has good outcomes for late-onset presentations and recommend that urgent transplantation should always be considered in Wilson’s disease presenting with acute liver failure

From evidence-base to practice: implementation of the Nurse Family Partnership programme in England

The aims of this article are to highlight the issues that are relevant to the implementation of a rigorously evidence-based programme of support, the Nurse Family Partnership programme, into a national system of care. Methods used are semi-structured interviews with families in receipt of the programme in the first 10 sites, with the nursing staff, with members of the central team guiding the initiative and with other professionals. Analyses of data collected during programme delivery evaluate fidelity of delivery. The results indicate that the programme is perceived in a positive light and take-up is high, with delivery close to the stated US objectives. Issues pertaining to sustainability are highlighted - in particular, local concerns about cost set against long-term rather than immediate gains. However, local investment is predominantly strong, with creative methods being planned for the future. Overall, the study shows that within an NHS system of care it is possible to deliver a targeted evidence-based programme

Neuroimaging correlates of brain injury in Wilson's disease: a multimodal, whole-brain MRI study

Wilson's disease is an autosomal-recessive disorder of copper metabolism with neurological and hepatic presentations. Chelation therapy is used to 'de-copper' patients but neurological outcomes remain unpredictable. A range of neuroimaging abnormalities have been described and may provide insights into disease mechanisms, in addition to prognostic and monitoring biomarkers. Previous quantitative MRI analyses have focussed on specific sequences or regions of interest, often stratifying chronically-treated patients according to persisting symptoms as opposed to initial presentation. In this cross-sectional study, we performed a combination of unbiased, whole-brain analyses on T1-weighted, fluid-attenuated inversion recovery, diffusion-weighted and susceptibility-weighted imaging data from 40 prospectively-recruited patients with Wilson's disease (age range 16-68). We compared patients with neurological (n = 23) and hepatic (n = 17) presentations to determine the neuroradiological sequelae of the initial brain injury. We also subcategorized patients according to recent neurological status, classifying those with neurological presentations or deterioration in the preceding six months as having 'active' disease. This allowed us to compare patients with active (n = 5) and stable (n = 35) disease and identify imaging correlates for persistent neurological deficits and copper indices in chronically-treated, stable patients. Using a combination of voxel-based morphometry and region-of-interest volumetric analyses, we demonstrate that grey matter volumes are lower in the basal ganglia, thalamus, brainstem, cerebellum, anterior insula and orbitofrontal cortex when comparing patients with neurological and hepatic presentations. In chronically-treated, stable patients, the severity of neurological deficits correlated with grey matter volumes in similar, predominantly subcortical regions. In contrast, the severity of neurological deficits did not correlate with the volume of white matter hyperintensities, calculated using an automated lesion segmentation algorithm. Using tract-based spatial statistics, increasing neurological severity in chronically-treated patients was associated with decreasing axial diffusivity in white matter tracts whereas increasing serum non-caeruloplasmin-bound ('free') copper and active disease were associated with distinct patterns of increasing mean, axial and radial diffusivity. Whole-brain quantitative susceptibility mapping identified increased iron deposition in the putamen, cingulate and medial frontal cortices of patients with neurological presentations relative to those with hepatic presentations and neurological severity was associated with iron deposition in widespread cortical regions in chronically-treated patients. Our data indicate that composite measures of subcortical atrophy provide useful prognostic biomarkers, whereas abnormal mean, axial and radial diffusivity are promising monitoring biomarkers. Finally, deposition of brain iron in response to copper accumulation may directly contribute to neurodegeneration in Wilson's disease

Constipation preceding Parkinson's disease: a systematic review and meta-analysis

AJN is funded by Parkinson’s UK (grant reference F-1201). AJL has received honoraria from Novartis, Teva, Meda, Boehringer Ingelheim, GSK, Ipsen, Lundbeck, Allergan and Orion. AS has received grant money from GE Healthcare and honoraria from UCB. AJN has received grants from Élan/Prothena Pharmaceuticals and from GE Healthcare