Density of Superfluid Helium Droplets

The classical integral cross sections of large superfluid 4He_N droplets and the number of atoms in the droplets (N=10^3-10^4) have been measured in molecular beam scattering experiments. These measurements are found to be in good agreement with the cross sections predicted from density functional calculations of the radial density distributions with a 10-90 % surface thickness of 5.7\AA. By using a simple model for the density profile of the droplets a thickness of about 6-8\AA is extracted directly from the data.Comment: 27 pages, REVTeX, 5 postscript figure

Aligned carbon nanotube–epoxy composites: the effect of nanotube organization on strength, stiffness, and toughness

10.1007/s10853-016-0228-6Journal of Materials Science512210005-1002

Tensile Strength of CNT Fibres: Characteristic Length, Stress Transfer and other Impact Factors

The initial strength hype over carbon nanotubes arose from predictions of the strength of individual graphene layers, encouraged by measurements of individual MWCNTs and SWCNT bundles in AFM [1, 2]. However, while the scientists were professionally explicit as to what they had measured, the publicity assumed that these figures could also be readily realized in materials made from these components. It\u2019s against a background of this overselling that we examine the gradual improvement in strength of macroscopically useful materials. Yarn-like fibres composed of carbon nanotubes made by the direct spinning process [3] have been used as the subject of this study. There have been occasional observations of strengths greater than 5 N/tex [4], which have served to maintain the enthusiasm for on-going developments. Here, we will re-examine those high strength reports in the context of the response of nanotubes aggregates to applied tensile stress

Aligned carbon nanotube–epoxy composites: the effect of nanotube organization on strength, stiffness, and toughness

10.1007/s10853-016-0228-6Journal of Materials Science512210005-1002

Mechanical Performance of CNT Fibres

The initial strength hype over carbon nanotubes arose from predictions of the strength of individual graphene layers, encouraged by measurements of individual MWCNTs and SWCNT bundles in AFM. The challenge for fibres composed of carbon nanotubes (CNTs) is to translate the impressive properties of the individual carbon nanotubes into the fibres. Yarn-like fibres composed of carbon nanotubes made by the direct spinning process have been used as the subject of this study. There have been occasional observations of strengths greater than 5 N/tex, which have served to maintain the enthusiasm for on-going developments. Here, we will re-examine those reports in the context of the response of nanotubes aggregates to applied tensile stress

Large-scale molecular dynamics simulations of high energy cluster impact on a diamond surface

Large-scale molecular dynamics simulations of high acceleration energy single cluster impacts on a diamond surface are performed in order to investigate the cluster surface interaction. The formation of the crater and of the multiple shockwaves at a cluster acceleration energy Ea=100 keV is studied in detail in this report. The two Ar961 impact simulations using and not using external symmetric region do not show any clear difference, so that the unspherical crater structure at the very beginning of the impact and the shockwave propagation directions do not result from the respective outer region representation but from the effect of the crystal structure of diamond. The impact simulation of a virtual hard spherical cluster demonstrates a deeper transient crater as well as a more pronounced final impact morphology while the impact-induced multi-layered shockwaves resemble those seen in the case of the normal cluster impact

CNT fibres - yarns between the extremes

The carbon nanotube community swims in the sea of superlatives. Researchers expect mechanical performance to achieve two extremes, an ultrastrong fibre taking us into space, and a superlubricant saving energy otherwise lost as heat. We examine CNT fibres in the light of traditional yarn science and present an interpretation of properties which combines aspects of these two extremes of performance