Quantitative LEED I-V and ab initio study of the Si(111)-3x2-Sm surface structure and the missing half order spots in the 3x1 diffraction pattern

We have used Low Energy Electron Diffraction (LEED) I-V analysis and ab initio calculations to quantitatively determine the honeycomb chain model structure for the Si(111)-3x2-Sm surface. This structure and a similar 3x1 recontruction have been observed for many Alkali-Earth and Rare-Earth metals on the Si(111) surface. Our ab initio calculations show that there are two almost degenerate sites for the Sm atom in the unit cell and the LEED I-V analysis reveals that an admixture of the two in a ratio that slightly favours the site with the lower energy is the best match to experiment. We show that the I-V curves are insensitive to the presence of the Sm atom and that this results in a very low intensity for the half order spots which might explain the appearance of a 3x1 LEED pattern produced by all of the structures with a 3x2 unit cell.Comment: 10 pages, 13 figures. Preliminary work presented at the the APS March meeting, Baltimore MD, 2006. To be published in Phys. Rev. B. April/May 200

Improved real-space genetic algorithm for crystal structure and polymorph prediction

Existing genetic algorithms for crystal structure and polymorph prediction can suffer from stagnation during evolution, with a consequent loss of efficiency and accuracy. An improved genetic algorithm is introduced herein which penalizes similar structures and so enhances structural diversity in the population at each generation. This is shown to improve the quality of results found for the theoretical prediction of simple model crystal structures. In particular, this method is demonstrated to find three new zero-temperature phases of the Dzugutov potential that have not been previously reported

Incremental change towards sustainability: integrating human and ecological factors for efficiency

This chapter presents case studies of two companies, one based in South Wales, UK, and the other in New South Wales, Australia. Both companies have successfully carried out incremental changes that have integrated economic aims with environmental improvements and local social sensitivity. We argue that the competitiveness of these companies is facilitated by their proactive and co-operative environmental management philosophy. A key capability underpinning the environmental success of both organisations is networking with regulators and with local community. Another is the systematic approach to human resource functions. The chapter thus raises suggestions concerning the integration of the human and ecological sustainability of corporations

Energy supplier involvement in English fuel poverty alleviation: a critical analysis of emergent approaches and implications for policy success

Over the last twenty-five years, fuel poverty in England has successfully transitioned from niche academic interest to mandated concern of the state. More recently still, government have opted to charge energy suppliers with primary delivery responsibility for fuel poverty programmes. The original contribution to knowledge made by this thesis is in offering a novel comparative analysis of the potential for the state and energy suppliers to effectively support fuel poor households. This research offers one of the first academic assessments of the new suite of policies championed by the coalition government formed in 2010. It is also amongst the first pieces of work to apply and critically assess the new official metric for fuel poverty, the Low Income, High Costs definition. By assessing delivery choices against the tenets of neoliberalism identified as guiding recent UK governments, the work further takes into account the motivations of policymakers. A diverse methodological approach is applied, incorporating policy evaluation, quantitative analysis, synthesis of existing literature, and professional engagement. This research establishes that in passing the Warm Homes and Energy Conservation Act 2000, politicians did not appreciate the demands of the commitment to eradicate fuel poverty by 2016. Subsequently, supplier obligations initially intended as a means of mitigating climate change have become the primary policy tool for tackling fuel poverty. The evidence presented here suggests, however, that suppliers are inherently poorly suited to this task for a variety of reasons: their access to the data required to successfully identify fuel poor households is limited; they fund activity in a manner that is unavoidably regressive; and the extent to which they are able to deliver programmes more efficiently than the state is, particularly for economic interventions, subject to question. It is consequently argued that, whilst supplier obligations are likely to appeal to an austerity-driven, neoliberal government as an expedient means of keeping expenditure away from the public purse and of limiting the role of the state, this work demonstrates that increased government involvement and greater political ambition will be required if fuel poverty policies are to be successful

STM and ab initio study of holmium nanowires on a Ge(111) Surface

A nanorod structure has been observed on the Ho/Ge(111) surface using scanning tunneling microscopy (STM). The rods do not require patterning of the surface or defects such as step edges in order to grow as is the case for nanorods on Si(111). At low holmium coverage the nanorods exist as isolated nanostructures while at high coverage they form a periodic 5x1 structure. We propose a structural model for the 5x1 unit cell and show using an ab initio calculation that the STM profile of our model structure compares favorably to that obtained experimentally for both filled and empty states sampling. The calculated local density of states shows that the nanorod is metallic in character.Comment: 4 pages, 12 figures (inc. subfigures). Presented at the the APS March meeting, Baltimore MD, 200

A tool to evaluate design performance in SMEs

PurposeThe creation of well‐designed products is widely acknowledged as an important contributor to company success. In principle, an effective design process, as part of the wider new product development (NPD) process, should result in well‐designed products. This paper aims to present a tool to enable a design team to evaluate their design process in a workshop setting, with a view to targeting improvements.Design/methodology/approachThis tool is based on literature and has been iteratively developed using a mixed research approach, including detailed exploratory cases and application in action research mode.FindingsThe resulting tool comprises two main components. A “process audit” based on process maturity principles, which targets the design‐related activities in NPD. The process audit enables a company team to identify improvement opportunities in the design process. A product audit enables perceptions towards product characteristics to be assessed. The audit tool does not seek to be a benchmarking tool, but aims to capture “good design” principles in a form which is accessible and useful to practitioners.Practical implicationsIn use, the tool enabled managers to balance their concern with meeting budget and timescale demands against the importance of producing well‐designed products. By first focusing on the tangible output of the design process – the product – practitioners are better able to understand the way in which design decisions influence product usability, desirability and producibility. Evidence from cases confirms the value and originality of this tool.Originality/valuePrevious tools addressing product development have focused on strategic and managerial concerns. This novel assessment tool focuses explicitly on design issues, within the wider context of NPD.</jats:sec