This paper reviews, synthesises and benchmarks new understandings relating to railway vibrations. Firstly, the effect of vibrations on passenger comfort is evaluated, followed by its effect on track performance. Then ground-borne vibration is discussed along with its effect on the structural response of buildings near railway lines. There is discussion of the most suitable mathematical and numerical modelling strategies for railway vibration simulation, along with mitigation strategies. Regarding ground borne vibration, structural amplification is discussed and how vibration mitigation strategies can be implemented. There is also a focus on determining how 'critical velocity' and 'track critical velocity' are evaluated-with the aim of providing clear design guidelines related to Rayleigh wave velocity. To aid this, conventional site investigation data is reviewed and related to critical velocity calculations. The aim is to provide new thinking on how to predict critical velocity from readily available conventional site investigation data.

We have developed colloidal synthesis methods to create nanoparticles (NPs) of tantalum nitride. The particle sizes and crystallinity can be controlled through the use of different organic solvents and reaction times; we demonstrate here NPs ranging in size from 2 to 23 nm. While electron microscopy and selected area diffraction demonstrate the synthesis of NPs of tantalum nitride (which may be partially oxidized), results from X-ray photoelectron spectroscopy reveal that the majority of the tantalum in our sample is present as an unidentified molecular-scale oxide species.

We apply a numerical model of the late Wisconsin (circa 20,000 years B.P.) Lake Michigan Lobe (LML), Laurentide Ice Sheet, to investigate how fine-grained subglacial sediment might influence lobe behavior, particularly rapid millennial-scale marginal oscillations observed in the geologic record. Over the Canadian Shield, we assume a rigid bed ("hard bedded") basal boundary condition. In areas overlain by fine-grained sediment ("soft bedded"), the base of the ice is coupled to a deformable sediment layer, using a rate-dependent stress-strain law. Geotechnical tests of clay-rich till depositext by the LML provide control for sediment rheologic parameters. Simulated cross-sectional profiles are consistent with reconstructions from geologic evidence. Time-dependent simulations suggest that a soft-bedded lobe could have reached steady state in about 20,000 years or less, in contrast to 50,000 to 60,000 years for an otherwise identical hard-bedded lobe. A soft-bedded lobe with sediment viscosity at the experimentally determined value is about twice as responsive to millennial-scale shifts in accumulation or ablation as a nonsliding hard-bedded lobe, but in both cases the response is slower than that indicated by the geologic record. Results suggest that while strong millennial-scale changes in accumulation and ablation can produce responses in hard-bedded or soft-bedded ice that are consistent with the geologic record, changes in subglacial sediment viscosity, even relatively modest changes (whether independent or in conjunction with climate change), might more readily account for millennial-and submillennial-scale fluctuations of the lobe margin. These observations do not exclude a role for sliding, but they do provide some perspective from which to evaluate relative contributions of the various processes that influence lobe behavior. to understanding late Quaternary history.We selected the Lake Michigan Lobe (LML) of the Laurentide Ice Sheet (LIS) (Figure 1) to investigate how a deforming substrate (hereafter called "soft bed") might influence ice sheet dynamics. We compare this with ice sheet behavior under identical conditions except for having a nonyielding substrate (hereafter called "hard bed"). The active behavior of the LML and similar lobes of the LIS has long been recognized [Dreimanis and Goldthwait, 1973;Wright, 1973;Clayton et al., 1985]. Common characteristics include soft sediments at their bases and episodic oscillation during retreat [Clark, 1994]. We focused on the LML, where the sediment record is accessible and regional lithostratigraphy 8717