Helium ion microscopy and energy selective scanning electron microscopy – two advanced microscopy techniques with complementary applications

Both scanning electron microscopes (SEM) and helium ion microscopes (HeIM) are based on the same principle of a charged particle beam scanning across the surface and generating secondary electrons (SEs) to form images. However, there is a pronounced difference in the energy spectra of the emitted secondary electrons emitted as result of electron or helium ion impact. We have previously presented evidence that this also translates to differences in the information depth through the analysis of dopant contrast in doped silicon structures in both SEM and HeIM. Here, it is now shown how secondary electron emission spectra (SES) and their relation to depth of origin of SE can be experimentally exploited through the use of energy filtering (EF) in low voltage SEM (LV-SEM) to access bulk information from surfaces covered by damage or contamination layers. From the current understanding of the SES in HeIM it is not expected that EF will be as effective in HeIM but an alternative that can be used for some materials to access bulk information is presented

The imperial war museum’s social interpretation project

This report represents the output from research undertaken by University of Salford and MTM London as part of the joint Digital R&D Fund for Arts and Culture, operated by Nesta, Arts Council England and the AHRC. University of Salford and MTM London received funding from the programme to act as researchers on the Social Interpretation (SI) project, which was led by the Imperial War Museum (IWM) and their technical partners, The Centre for Digital Humanities, University College London, Knowledge Integration, and Gooii. The project was carried out between October 2011 and October 2012

Self-assembled germanium islands grown on (001) silicon substrates by low-pressure chemical vapor deposition

The time evolution of self-assembled Ge islands, during low-pressure chemical vapor deposition (LPCVD) of Ge on Si at 650 Deg C using high growth rates, has been investigated by atomic force microscopy, transmission electron microscopy, and Rutherford backscattering spectrometry. We have found three different island structures The smallest islands are "lens-shaped" and characterized by a rather narrow size distribution, ~4nm high and ~20nm wide. Next to form are a distinct population of multifaceted "dome shaped" islands, up to 25nm high and 80-150 nm wide. Finally, the largest islands that form are square-based truncated pyramids with a very narrow size distribution ~50nm high and ~250nm wide. The pyramidal islands normally seen in the intermediate size range (~150nm) are not observed. The small lens-shaped islands appear to be defect free, while some of the multifaceted islands as well as all the large truncated pyramids contain misfit dislocations. The existence of multifaceted islands, in the size range where multifaceted "dome shaped" islands have previously been reported, is attributed to the high growth rate used. Furthermore, under the growth conditions used, the truncated-pyramid-shaped islands are characterized by a very narrow size distribution

The self-care for people initiative: the outcome evaluation.

To determine the effects of a community-based training programme in self-care on the lay population

Self-care in primary care: findings from a longitudinal comparison study.

To examine the effects of self-care training workshops for primary healthcare workers on frequently attending patients

Tunable reflection minima of nanostructured antireflective surfaces

Broadband antireflection schemes for silicon surfaces based on the moth-eye principle and comprising arrays of subwavelength-scale pillars are applicable to solar cells, photodetectors, and stealth technologies and can exhibit very low reflectances. We show that rigorous coupled wave analysis can be used to accurately model the intricate reflectance behavior of these surfaces and so can be used to explore the effects of variations in pillar height, period, and shape. Low reflectance regions are identified, the extent of which are determined by the shape of the pillars. The wavelengths over which these low reflectance regions operate can be shifted by altering the period of the array. Thus the subtle features of the reflectance spectrum of a moth-eye array can be tailored for optimum performance for the input spectrum of a specific application

A three-dimensional electrostatic actuator with a locking mechanism for a new generation of atom chips

A micromachined three-dimensional electrostatic actuator that is optimized for aligning and tuning optical microcavities on atom chips is presented. The design of the 3D actuator is outlined in detail, and its characteristics are verified by analytical calculations and finite element modelling. Furthermore, the fabrication process of the actuation device is described and preliminary fabrication results are shown. The actuation in the chip plane which is used for mirror positioning has a working envelope of 17.5 ?m. The design incorporates a unique locking mechanism which allows the out-of-plane actuation that is used for cavity tuning to be carried out once the in-plane actuation is completed. A maximum translation of 7 ?m can be achieved in the out-of-plane direction

Animal-Drawn Conservation-Tillage Planter for Small Farms in the Developing World

South Africa has the potential to serve as a bridge between large scale farming in developed nations and the small scale operations of subsistence farmers in developing nations. It has a mix of both large-scale modern farms and small farms, which use a range of different farming practices and products. There is a gap between the tractors used by large scale South African farmers and the equipment available to the small farm holders. This research effort aims to fill a portion of that gap. There is a particular need for implements that take advantage of newer conservation methods, such as no-till, and make that technology available for small farm holders. International shipping tends to be costly, increasing the end cost of planters manufactured in other countries, making in-country manufacturing desirable. The objectives of this work included designing, building, and testing a small animal-drawn no-till planter that could be manufactured in a rural town in South Africa and is simple and easy for men, women and older children to use. A prototype was manufactured with basic machine shop equipment and skills. The prototype was then refined and tested. Measurements included draft, seed depth, and seed spacing, with cowpeas used as a representative crop. The average draft for the prototype was 796 N (179 lbf), low enough to be pulled by two draft animals weighing 816.5 kg (1800 lbs) total. The target seed placement depth for cowpeas of 2 cm was achieved within 25% most of the time, and the target seed spacing of 10 cm was achieved within 50%. The residue managers for moving straw from the row, and the press wheels for covering the seed with soil, both performed their intended functions. The planter was also found to be easy to lift at the tongue with one hand and easily operated from the side from which animals are typically driven. This planter could meet the planting and conservation needs of many small farm holders who have access to animal power but not to machine power

Agent-based autonomous systems and abstraction engines: Theory meets practice

We report on experiences in the development of hybrid autonomous systems where high-level decisions are made by a rational agent. This rational agent interacts with other sub-systems via an abstraction engine. We describe three systems we have developed using the EASS BDI agent programming language and framework which supports this architecture. As a result of these experiences we recommend changes to the theoretical operational semantics that underpins the EASS framework and present a fourth implementation using the new semantics