High Speed Sintering – Continuing Research into a New Rapid Manufacturing Process

High Speed Sintering (HSS) is an emerging layer manufacturing technique aiming to break into the lucrative field of Rapid Manufacturing (RM). The process is likened to Selective Laser Sintering (SLS), however, instead of a laser dictating the sintered cross sectional area of each layer, the desired area is first printed using a Radiation Absorbing Material (RAM) and then sintered using an inexpensive infrared lamp. This paper begins by describing the sintering process in more detail and then outlining the overall manufacturing cycle. It then continues by describing the experiments performed to investigate the current problem concerning the hardness of excess powder within the powder bed. This problem arose due to the continual exposure of the whole bed to infrared radiation from the lamp. The experiments showed that as the power of the IR lamp increased, the hardness of the bed also increased. Furthermore, at higher IR power levels it was found the excess powder produced a solid tile which could only be broken down by a glass bead blaster.Mechanical Engineerin

Do teachers matter? Measuring the variation in teacher effectiveness in England

Using a unique primary dataset for the UK, we estimate the effect of individual teachers on student outcomes, and the variability in teacher quality. This links over 7000 pupils to the individual teachers who taught them, in each of their compulsory subjects in the high-stakes exams at age 16. We use point-in-time fixed effects and prior attainment to control for pupil heterogeneity. We find considerable variability in teacher effectiveness, a little higher than the estimates found in the few US studies. We also corroborate recent findings that observed teachers’ characteristics explain very little of the differences in estimated effectiveness.education, test scores, teacher effectiveness

Modelling and Refinement in CODA

This paper provides an overview of the CODA framework for modelling and refinement of component-based embedded systems. CODA is an extension of Event-B and UML-B and is supported by a plug-in for the Rodin toolset. CODA augments Event-B with constructs for component-based modelling including components, communications ports, port connectors, timed communications and timing triggers. Component behaviour is specified through a combination of UML-B state machines and Event-B. CODA communications and timing are given an Event-B semantics through translation rules. Refinement is based on Event-B refinement and allows layered construction of CODA models in a consistent way.Comment: In Proceedings Refine 2013, arXiv:1305.563

Responding to the NHS and social care workforce crisis: the enhancement of opportunities through collaborative partnerships

Purpose: This paper will describe and analyse the development of a higher apprenticeship route which enables learners to access both higher education and health and social care professional programmes. The underpinning rationale is the urgent workforce crisis in health and social care services. Design/methodology/approach: We will review the multiple drivers which stimulated course development and the creation of a community of practice to ensure quality management. A student case study illustrates the potential of an apprenticeship to enable both personal and professional development. Findings: The paper provides insight into working with a number of further education colleges, how to ensure consistency in delivery and assessment and the strategies which contribute to quality assurance. This case study illustrates the potential of work based learning to transform lives and to provide the workforce required by our public services. Practical Implications: This paper explores the lessons learnt from setting up a new system and the processes that need to be in place for success, when higher and further education collaborate to meet employer needs. Social Implications: The paper discusses the potential of widening access into higher education, the positive impact on recruitment to professional courses and the long term effect on the public service workforce. Value of the paper: The government is committed to expansion of apprenticeship learning in health and social care. This paper shares our experience of working with a range of employers and education providers, the challenges and successes and recommendations for development

The online learning hive: transfer to practice within a MOOC community of educators

We describe the analysis of online engagement by participants in a massive online open course (MOOC) on teaching with tablets and mobile devices. The MOOC was aimed at educators, prompting them to use tablets in novel and innovative ways in their own educational practice. The MOOC included instructor-led and student-led activities and had a substantial social and constructivist component. We analysed the online discussions (across several platforms) and identified clear and frequent examples of participants providing evidence of their own practice, and many examples of peer to peer learning. While the MOOC was designed to facilitate the transfer of novel teaching approaches to the participant's practice, there were fewer examples of this happening. A surprising finding was the degree to which peer support encouraged participants to engage more fully in the MOOC

Ubiquitous computing devices in the training of teacher-trainers

In September 2014, the computing curriculum in English schools changed to one with a much greater emphasis on computer science. However, 66% of existing ICT teachers are non-specialist and require significant continuing professional development (CPD) to deliver this new curriculum. One initiative to provide this is the Computing At School (CAS) Master Teacher programme. This paper describes some physical computing projects that were used in training a cohort of Master Teachers, preparing them to deliver both improved lessons in classrooms and CPD tailored for the requirements of their peers

The strength and timing of the mitochondrial bottleneck in salmon suggests a conserved mechanism in vertebrates

In most species mitochondrial DNA (mtDNA) is inherited maternally in an apparently clonal fashion, although how this is achieved remains uncertain. Population genetic studies show not only that individuals can harbor more than one type of mtDNA (heteroplasmy) but that heteroplasmy is common and widespread across a diversity of taxa. Females harboring a mixture of mtDNAs may transmit varying proportions of each mtDNA type (haplotype) to their offspring. However, mtDNA variants are also observed to segregate rapidly between generations despite the high mtDNA copy number in the oocyte, which suggests a genetic bottleneck acts during mtDNA transmission. Understanding the size and timing of this bottleneck is important for interpreting population genetic relationships and for predicting the inheritance of mtDNA based disease, but despite its importance the underlying mechanisms remain unclear. Empirical studies, restricted to mice, have shown that the mtDNA bottleneck could act either at embryogenesis, oogenesis or both. To investigate whether the size and timing of the mitochondrial bottleneck is conserved between distant vertebrates, we measured the genetic variance in mtDNA heteroplasmy at three developmental stages (female, ova and fry) in chinook salmon and applied a new mathematical model to estimate the number of segregating units (N(e)) of the mitochondrial bottleneck between each stage. Using these data we estimate values for mtDNA Ne of 88.3 for oogenesis, and 80.3 for embryogenesis. Our results confirm the presence of a mitochondrial bottleneck in fish, and show that segregation of mtDNA variation is effectively complete by the end of oogenesis. Considering the extensive differences in reproductive physiology between fish and mammals, our results suggest the mechanism underlying the mtDNA bottleneck is conserved in these distant vertebrates both in terms of it magnitude and timing. This finding may lead to improvements in our understanding of mitochondrial disorders and population interpretations using mtDNA data