Ion-beam technology and applications

Ion propulsion research and development yields a mature technology that is transferable to a wide range of nonpropulsive applications, including terrestrial and space manufacturing. A xenon ion source was used for an investigation into potential ion-beam applications. The results of cathode tests and discharge-chamber experiments are presented. A series of experiments encompassing a wide range of potential applications is discussed. Two types of processes, sputter deposition, and erosion were studied. Some of the potential applications are thin-film Teflon capacitor fabrication, lubrication applications, ion-beam cleaning and polishing, and surface texturing

Two dimensional XXZ-Ising model on square-hexagon lattice

We study a two dimensional XXZ-Ising on square-hexagon (4-6) lattice with spin-1/2. The phase diagram of the ground state energy is discussed, shown two different ferrimagnetic states and two type of antiferromagnetic states, beside of a ferromagnetic state. To solve this model, it could be mapped into the eight-vertex model with union jack interaction term. Imposing exact solution condition we find the region where the XXZ-Ising model on 4-6 lattice have exact solutions with one free parameter, for symmetric eight-vertex model condition. In this sense we explore the properties of the system and analyze the competition of the interaction parameters providing the region where it has an exact solution. However the present model does not satisfy the \textit{free fermion} condition, unless for a trivial situation. Even so we are able to discuss their critical points region, when the exactly solvable condition is ignored.Comment: 5 pages, 5 figure

Unpacking the tensions between local and national skills policy: employers, colleges and Local Enterprise Partnerships as collaborative anchors

Inherent tensions exist in skills policies that aim to combine national economic growth and productivity with localised implementation for education and training. This is particularly apparent in the over-emphasis on employer engagement in national education and training policy, where the localisation of skills formation is particularly envisioned through employer engagement. Yet further education colleges have acted as anchors within local skills ecosystems working successfully with employers, often through Local Enterprise Partnerships (LEPs), providing the key bridging mechanism between national skills policy and localised enactment. We unpack the tensions between national and local skills policy by presenting a case study of a local skills ecosystem. Through interviews with key stakeholders – representatives from the local college, the LEP, and employers – we deploy Stephen J. Ball’s approach to policy enactment to map the complex processes and tensions involved in the translation of national skills policy into local skills systems. Our findings highlight the critical role of colleges as anchor institutions in local skills ecosystems, with employers and LEPs working as ‘collaborative anchors’ in the policy cycle. We present the concept of ‘local collaborative anchors’ as a heuristic device for understanding tensions within local skills ecosystems and national skills policy enactment

Quantum Monte Carlo calculations of six-quark states

The variational Monte Carlo method is used to find the ground state of six quarks confined to a cavity of diameter R_c, interacting via an assumed non-relativistic constituent quark model (CQM) Hamiltonian. We use a flux-tube model augmented with one-gluon and one-pion exchange interactions, which has been successful in describing single hadron spectra. The variational wave function is written as a product of three-quark nucleon states with correlations between quarks in different nucleons. We study the role of quark exchange effects by allowing flux-tube configuration mixing. An accurate six-body variational wave function is obtained. It has only ~13% rms fluctuation in the total energy and yields a standard deviation of ~<.1%; small enough to be useful in discerning nuclear interaction effects from the large rest mass of the two nucleons. Results are presented for three values of the cavity diameter, R_c=2, 4, and 6 fm. They indicate that the flux-tube model Hamiltonian with gluon and pion exchange requires revisions in order to obtain agreement with the energies estimated from realistic two-nucleon interactions. We calculate the two-quark probability distribution functions and show how they may be used to study and adjust the model Hamiltonian.Comment: 49 pages, 13 figures, submitted to Phys. Rev.

Optimised multi-camera systems for dimensional control in factory environments

As part of the United Kingdom’s Light Controlled Factory project, University College London aims to develop a large-scale multi-camera system for dimensional control tasks in manufacturing, such as part assembly and tracking. Accuracy requirements in manufacturing are demanding, and improvements in the modelling and analysis of both camera imaging and the measurement environment are essential. A major aspect to improved camera modelling is the use of monochromatic imaging of retro-reflective target points, together with a camera model designed for a particular illumination wavelength. A small-scale system for laboratory testing has been constructed using eight low-cost monochrome cameras with C-mount lenses on a rigid metal framework. Red, green and blue monochromatic light-emitting diode ring illumination has been tested, with a broadband white illumination for comparison. Potentially, accuracy may be further enhanced by the reduction in refraction errors caused by a non-homogeneous factory environment, typically manifest in varying temperatures in the workspace. A refraction modelling tool under development in the parallel European Union LUMINAR project is being used to simulate refraction in order to test methods which may be able to reduce or eliminate this effect in practice

Developing a quality assurance metric: a panoptic view

This article is a post-print of the published article that may be accessed at the link below. Copyright @ 2006 Sage Publications.There are a variety of techniques that lecturers can use to get feedback on their teaching - for example, module feedback and coursework results. However, a question arises about how reliable and valid are the content that goes into these quality assurance metrics. The aim of this article is to present a new approach for collecting and analysing qualitative feedback from students that could be used as the first stage in developing more reliable quality assurance metrics. The approach, known as the multi-dimensional crystal view, is based on the belief that individuals have different views on the benefits that the embedded process in a system can have on the behaviour of the system. The results of this study indicate that in the context of evaluation and feedback methods, the multi-dimensional approach appears to provide the opportunity for developing more effective student feedback mechanisms

Product Service System Innovation in the Smart City

Product service systems (PSS) may usefully form part of the mix of innovations necessary to move society toward more sustainable futures. However, despite such potential, PSS implementation is highly uneven and limited. Drawing on an alternate socio-technical perspective of innovation, this paper provides fresh insights, on among other things the role of context in PSS innovation, to address this issue. Case study research is presented focusing on a use orientated PSS in an urban environment: the Copenhagen city bike scheme. The paper shows that PSS innovation is a situated complex process, shaped by actors and knowledge from other locales. It argues that further research is needed to investigate how actors interests shape PSS innovation. It recommends that institutional spaces should be provided in governance landscapes associated with urban environments to enable legitimate PSS concepts to co-evolve in light of locally articulated sustainability principles and priorities