Investigating the evolving microstructure of lithium metal electrodes in 3D using X-ray computed tomography.

The growth of electrodeposited lithium microstructures on metallic lithium electrodes has prevented their use in rechargeable lithium batteries due to early performance degradation and safety implications. Understanding the evolution of lithium microstructures during battery operation is crucial for the development of an effective and safe rechargeable lithium-metal battery. This study employs both synchrotron and laboratory X-ray computed tomography to investigate the morphological evolution of the surface of metallic lithium electrodes during a single cell discharge and over numerous cycles, respectively. The formation of surface pits and the growth of mossy lithium deposits through the separator layer are characterised in three-dimensions. This has provided insight into the microstructural evolution of lithium-metal electrodes during rechargeable battery operation, and further understanding of the importance of separator architecture in mitigating lithium dendrite growth.

On compression and damage evolution in two thermoplastics.

The well-known Taylor cylinder impact test, which follows the impact of a flat-ended cylindrical rod onto a rigid stationary anvil, is conducted over a range of impact speeds for two polymers, polytetrafluoroethylene (PTFE) and polyetheretherketone (PEEK). In previous work, experiments and a model were developed to capture the deformation behaviour of the cylinder after impact. These works showed a region in which spatial and temporal variation of both longitudinal and radial deformation provided evidence of changes in phase within the material. In this further series of experiments, this region is imaged in a range of impacted targets at the Diamond synchrotron. Further techniques were fielded to resolve compressed regions within the recovered polymer cylinders that showed a fracture zone in the impact region. The combination of macroscopic high-speed photography and three-dimensional X-ray imaging has identified the development of failure with these polymers and shown that there is no abrupt transition in behaviours but rather a continuous range of responses to competing operating mechanisms. The behaviours noted in PEEK in these polymers show critical gaps in understanding of polymer high strain-rate response.

Assessment of prognosis in cutaneous malignant melanoma.

A retrospective study of 103 patients with histologically proved cutaneous malignant melanoma was made in order to assess the validity of a simple prognostic index, based upon a multivariate analysis of weighted pathological and clinical factors, in predicting the expected outcome in a given case. The results of the study were almost identical to those observed by Cochran (1968); 16 per cent of the patients with a low prognostic index (less than 20) died or developed recurrence of melanoma during the period of follow-up, in contrast to those with a high prognostic index (greater than 25) of whom 64 per cent were similarly affected. It is concluded that the predicted outcome based upon such an index is valid for the 5 postoperative years in some 90 per cent of patients with cutaneous malignant melanoma. It is suggested that the use of such an index may be of great value in selecting patients in whom the expected outcome to surgical therapy is poor and in whom adjuvant therapy may be of value.

Scalp and cranial substitution with autotransplanted greater omentum using microvascular anastomosis.

A case is described whereby a large defect of scalp and cranium was successfully covered using autotransplanted greater omentum, revascularized by microsurgical techniques.