Investigating the impact of non-local parallel transport in tokamak edge plasmas

The thin region of plasma at the edge of a tokamak, as the boundary condition to the confined plasma in the core, plays an oversized role in the performance of such devices. As such, the topic of exhaust physics is central to the ongoing effort to make magnetically confined fusion a viable approach to clean energy generation. A defining feature of this edge plasma, called the scrape-off layer (SOL), is a large temperature gradient in the direction parallel to the magnetic field. Large temperature drops are probably crucial to avoid excessive heat loads to the solid components which make up the walls of the device. However, their presence means that classical transport models, which assume the plasma is at or close to local thermodynamic equilibrium (LTE) and which are used widely in SOL modelling, can lose their predictive power [1-3]. The aim of this thesis is to investigate the extent of this effect in detail by performing kinetic simulations of parallel transport in SOL plasmas, with a focus on the electrons. There is an emphasis on quantifying the modelling uncertainties that exist in classical ('fluid') approaches to SOL simulations by performing self-consistent comparisons between kinetic and fluid models. To do this, the one-dimensional SOL kinetic code SOL-KiT has been used [4]. By extending the capabilities of this code, reducing its computational expense, and developing a standalone atomic physics code (all of which are described), it has been possible to study electron kinetics in a range of conditions relevant to current and future tokamaks. A number of distinct investigations have been performed. Firstly, it has been shown that fluid models are in fact very good at capturing the transfer of energy between ions and electrons in SOL plasmas. Secondly, it is demonstrated that a kinetic treatment leads to significant differences in parallel conductive heat transport and behaviour at the wall boundary, both of which contribute to modified temperature profiles. A set of simple scaling laws for these effects has been proposed. Finally, the effect of non-LTE electrons on plasma-atomic physics has been investigated. Here, strongly enhanced reaction rates due to the form of the electron velocity distribution have been observed, but this effect is largely reversed when considered alongside the modified temperature profiles.Open Acces

Реконструкция системы электроснабжения корпуса мостов ОАО "Гомсельмаш" в связи с внедрением нового технологического оборудования на участке обработки чугунных изделий

Research into the music industry has for a long time been almost exclusively dominated by a focus on the production of albums and songs. In recent years, however, cities such as Stockholm have seen the growth of a profitable and varied music services industry producing everything from remixes to music marketing strategies. Standing at the forefront of this growth industry are a large number of firms attempting to combine in innovative ways music and ICT. This can take a variety of forms, for instance: selling and distributing music over the internet; web design and computerised advertising services tailored to music products; software design focused on multimedia products and virtual instruments; high-tech post-production and mixing services; and virtual centres and communities of music industry actors. The article will examine these activities within the city in attempt to measure the direction and cohesiveness of the emerging sector. The article concludes by arguing that these type of new industrial synergies tell us much about the way industrial innovations are formed in an inter-industry and inter-cluster environment, and the future competitiveness and shape of the music industry. In particular, the article argues that evidence from Stockholm points to the emergence of a post-industrial musical economy

Development of a core outcome set for traumatic brachial plexus injuries (COMBINE): a study protocol

Introduction: Traumatic brachial plexus injury (TBPI) involves major trauma to the large nerves of the arm which control the movement and sensation. Fifty percent of injuries result in complete paralysis of the arm with many other individuals having little movement, sensation loss and unremitting pain. The injury often causes severe and permanent disability affecting work and social life, with an estimated cost to the NHS and the economy of £35 million per annum. Advances in microsurgery have resulted in an increase in interventions aimed at reconstructing these injuries. However, data to guide evidence-based decisions is lacking. Different outcomes are used across studies to assess the effectiveness of treatments. This has impeded our ability to synthesise results to determine which treatments work best. Studies frequently report short-term clinical outcomes but rarely report longer-term outcomes, and those focused on quality of life. This project aims to produce a Core Outcome Set (COS) for surgical and conservative management of TBPI. The TBPI COS will contain a minimum set of outcomes to be reported and measured in effectiveness studies and collected through routine clinical care. Methods and analysis: This mixed-methods project will be conducted in two phases. In phase 1 a long-list of patient-reported and clinical outcomes will be identified through a systematic review. Interviews will then explore outcomes important to patients. In phase 2 the outcomes identified across the systematic review and interviews will be included in a three round online Delphi exercise aiming to reach consensus on the COS. The Delphi process will include patient and healthcare participants. A consensus meeting will be held to achieve the final COS. Ethics and dissemination: The use of a COS in TBPI will increase the relevance of research and clinical care to all stakeholders, facilitate evidence synthesis and evidence-based decision making. The study has ethical approval

Scaling laws for electron kinetic effects in tokamak scrape-off layer plasmas

Tokamak edge (scrape-off layer) plasmas can exhibit non-local transport in the direction parallel to the magnetic field due to steep temperature gradients. This effect along with its consequences has been explored at equilibrium for a range of conditions, from sheath-limited to detached, using the 1D kinetic electron code SOL-KiT, where the electrons are treated kinetically and compared to a self-consistent fluid model. Line-averaged suppression of the kinetic heat flux (compared to Spitzer-Harm) of up to 50% is observed, contrasting with up to 98% enhancement of the sheath heat transmission coefficient, $\gamma_e$. Simple scaling laws in terms of basic SOL parameters for both effects are presented. By implementing these scalings as corrections to the fluid model, we find good agreement with the kinetic model for target electron temperatures. It is found that the strongest kinetic effects in $\gamma_e$ are observed at low-intermediate collisionalities, and tend to increase at increasing upstream densities and temperatures. On the other hand, the heat flux suppression is found to increase monotonically as upstream collisionality decreases. The conditions simulated encompass collisionalities relevant to current and future tokamaks.Comment: 24 pages, 14 figure

ReMKiT1D -- A framework for building reactive multi-fluid models of the tokamak Scrape-Off Layer with coupled electron kinetics in 1D

In this manuscript we present the recently developed flexible framework for building both fluid and electron kinetic models of the tokamak Scrape-Off Layer in 1D - ReMKiT1D (Reactive Multi-fluid and Kinetic Transport in 1D). The framework can handle systems of non-linear ODEs, various 1D PDEs arising in fluid modelling, as well as PDEs arising from the treatment of the electron kinetic equation. As such, the framework allows for flexibility in fluid models of the Scrape-Off Layer while allowing the easy addition of kinetic electron effects. We focus on presenting both the high-level design decisions that allow for model flexibility, as well as the most important implementation aspects. A significant number of verification and performance tests are presented, as well as a step-by-step walkthrough of a simple example for setting up models using the Python interface

Psychological consequences of Traumatic Upper Limb Peripheral Nerve Injury: A Systematic Review

Introduction Traumatic upper limb peripheral nerve injuries significantly impact individuals’ function and ability to return to work. Patients with peripheral nerve injury experience ongoing psychological impairments for which they are not routinely treated. The aim of this review was to investigate the psychological consequences of traumatic upper limb peripheral nerve injury. Methods A systematic review of MEDLINE, Embase, PsycINFO, CINAHL, AMED, BNI, the Cochrane libraries and grey literature up to October 2015 was undertaken. Two reviewers independently assessed methodological quality in accordance with Cochrane Collaboration recommendations. Eligibility criteria comprised: adults or adolescents with traumatic upper limb peripheral nerve injury using any measurement of psychological well-being. Results Six studies ( n = 245) met the inclusion criteria. Methodological quality varied widely. Evidence of post-traumatic stress disorder at one month, which decreased over time, was reported in three studies. Two studies found a statistically significant correlation between the early presence of post-traumatic stress disorder and reduction in function at 12 or more months. Limited information was available on anxiety, depression and mental quality of life. Combined nerve injuries (in two studies) had significantly higher levels of post-traumatic stress disorder, at one month, compared to those with an isolated nerve injury. Conclusion There is some evidence of early post-traumatic stress disorder following traumatic upper limb peripheral nerve injury, which may have an impact on functional outcome. However, high-quality studies using prospective cohorts are required to further evaluate the psychological aspects associated with this traumatic injury. </jats:sec

Preadolescent presentation of a lumbar chordoma: results of vertebrectomy and fibula strut graft reconstruction at 8 years

Chordoma is a tumour of notochordal origin which usually involves the sacrum or skull base presenting in adulthood. Chordoma in a mobile spinal segment is infrequent and the authors report an extremely rare presentation of L3 chordoma in a child aged 7 years. Although a benign tumour, mobile segment chordoma is more locally aggressive, more likely to metastasise and has a poorer 5 year survival than sacral and clival lesions. Wide surgical excision and reconstruction is the treatment of choice in vertebral chordoma. This case was treated with staged vertebrectomy and fibular strut graft reconstruction and the results of clinical and radiological follow up at 8 years are presented

High Median Nerve Paralysis:Is the Hand of Benediction or Preacher's Hand A Correct Sign?

High median nerve injuries are commonly presented in textbooks as adopting the typical posture of hand of benediction or preacher’s hand. This study aimed to show that the hand of benediction or preacher’s hand is incorrectly associated with a high median nerve paralysis. METHODS: A retrospective review of four cases with a high median nerve injury is presented. Diagnosis of a high median nerve injury was performed by means of intraoperative findings, electrodiagnostic studies, or ultrasound imaging. None of the patients presented in this study had a hand of benediction on physical examination despite the presence of a high median nerve lesion. RESULTS: All four patients with high median nerve injuries showed a similar hand posture when attempting to make a fist. Firstly, the index finger still flexed at the metacarpophalangeal joint because of the ulnar innervated interossei muscles. Secondly the thumb is completely abducted at the carpometocarpal joint and extended at the interphalangeal joint. Lastly, middle finger flexion is possible due to dual innervation of its flexor digitorum profundus by the ulnar nerve as well as due to the quadriga phenomenon. CONCLUSIONS: The clinical appearance of a high median nerve palsy is different from the classical hand of benediction or preacher’s hand posture pointing finger. We have shown that this incorrect association can result in delayed referral of patients with high median nerve injuries

Development of a core outcome set for traumatic brachial plexus injury

The aim of the present study was to reach international consensus on the minimum set of outcomes to measure and report in adult traumatic brachial plexus injury care and research. This would facilitate comparison of outcomes from different centres and meta-analysis in research. A list of outcomes was developed from a systematic review (n = 54) and patient interviews (n = 12). The outcomes were rated in a three-round online Delphi survey completed by international surgeons, patients and therapists. Two online consensus meetings with patients and clinicians ratified the final core outcome set. A total of 72 people (20 surgeons, 21 patients, 31 therapists) from 19 countries completed all survey rounds. Thirty-eight people from nine countries attended separate patient (n = 13) and clinician consensus (n = 25) meetings. Outcomes were included if recommended by more than 85% of contributors. Pain, voluntary movement and carrying out a daily routine are the core outcome domains that should be assessed and reported when treating and researching adults with a traumatic brachial plexus injury

Neighbourhood cohesion and mental wellbeing among older adults:A mixed methods approach

There is now a body of evidence that demonstrates strong links between neighbourhood characteristics and mental health and wellbeing. There is an increasing interest in how this relationship varies for individuals of different ages. Understanding the link between neighbourhood and wellbeing for older adults is of particular significance, given the changing age structure of the population and the desire among policy makers and practitioners to promote healthy and active ageing. This paper provides further evidence on the nature and strength of the link between individual perceptions of neighbourhood belonging and mental wellbeing among those over age fifty using both qualitative and quantitative data from three British cohort studies. Between 2008 and 2011 quantitative data were collected from 10,312 cohort members, and 230 of them took part in qualitative biographical interviews.Quantitative analysis confirms that there is a moderate association between neighbourhood cohesion and wellbeing measured at the individual level in each of the three cohorts. This association persists after controlling for a range of covariates including personality. The association between neighbourhood cohesion and wellbeing is stronger for individuals in the older two cohorts than in the younger cohort.Using qualitative biographical interviews with 116 men and 114 women we illustrate how individuals talk about their sense of neighbourhood belonging. The importance of social participation as a mechanism for promoting neighbourhood belonging, and the use of age and life stage as characteristics to describe and define neighbours, is clear. In addition, the qualitative interviews point to the difficulties of using a short battery of questions to capture the varied and multi-dimensional nature of neighbourhood relations.<br/