Monitoring and Mitigating Particulate Matter Deposition on Decorative Surfaces: Current and Future Approaches in the Palace of Westminster

ABSTRACT

Research into dust deposition rates on the wall paintings in the State Apartments at the Palace of Westminster, London, UK, began during the restoration of the encaustic floor tiles. The study has broadened to inform day-to-day preventive care for the extensive fine art collections on display and the intricately decorated Gothic interiors, providing a powerful tool for the forthcoming restoration and renewal of the Palace. Different monitoring methods, using optical microscopy, macro-photography and software-based image analysis, were investigated. Qualitative analysis with SEM-EDX and optical microscopy allowed the identification of a number of anthropogenic, geogenic and biological sources of particulate matter, while quantitative results elucidated deposition trends, highlighting both seasonal and works-related impacts. Results indicated that mitigation measures taken to protect works of art and limit the diffusion and deposition of particulate matter on surrounding surfaces were successful. A new dust monitoring method, based on imaging of vertical surfaces and on a recently developed image analysis workflow (CHIJ) operated in open-source software (ImageJ) was trialled alongside more traditional methods for measuring dust deposition through collection of particulate matter on proxies. Results showed significant discrepancies between data acquired directly on wall painting surfaces as compared to horizontal glass slides. The advantages, limitations and complementarity of both monitoring methods were identified, and their potential contributions to the development of data-driven conservation approaches for heritage sites were assessed. The relatively low-tech methods and equipment used present useful and adapted tools for collection managers and conservators to inform their decision-making processes.     

Side-sloped surfaces substantially affect lower limb running kinematics

Running on side-sloped surfaces is a common obstacle in the environment; however, how and to what extent the lower extremity kinematics adapt is not well known. The purpose of this study was to determine the effects of side-sloped surfaces on three-dimensional kinematics of hip, knee, and ankle during stance phase of running. Ten healthy adult males ran barefoot along an inclinable runway in level (0°) and side-sloped (10° up-slope and down-slope inclinations, respectively) configurations. Right hip, knee, and ankle angles along with their time of occurrence were analysed using repeated measures MANOVA. Up-slope hip was more adducted (p = 0.015) and internally rotated (p = 0.030). Knee had greater external rotations during side-sloped running at heel-strike (p = 0.005), while at toe-off, it rotated externally and internally during up-slope and down-slope running, respectively (p = 0.001). Down-slope ankle had greatest plantar flexion (p = 0.001). Up-slope ankle had greatest eversion compared with down-slope (p = 0.043), while it was more externally rotated (p = 0.030). These motion patterns are necessary to adjust the lower extremity length during side-sloped running. Timing differences in the kinematic events of hip adduction and external rotation, and ankle eversion were observed (p = 0.006). Knowledge on these alterations is a valuable tool in adopting strategies to enhance performance while preventing injury.     

CPn中的齐次曲面

从齐性曲面的等距群出发,讨论CPn中的齐性曲面,得到了CPn中等距群为2维的齐性曲面的分类,并且用李群与活动标价相结合的方法给出了CP2中齐性曲面的分类定理的证明。