Rarefaction wave in relativistic steady magnetohydrodynamic flows

We construct and analyze a model of the relativistic steady-state magnetohydrodynamic (MHD) rarefaction that is induced when a planar symmetric flow (with one ignorable Cartesian coordinate) propagates under a steep drop of the external pressure profile. Using the method of self-similarity we derive a system of ordinary differential equations that describe the flow dynamics. In the specific limit of an initially homogeneous flow we also provide analytical results and accurate scaling laws. We consider that limit as a generalization of the previous Newtonian and hydrodynamic solutions already present in the literature. The model includes magnetic field and bulk flow speed having all components, whose role is explored with a parametric study.Comment: 12 pages, Accepted in Physics of Plasma

Rarefaction acceleration in magnetized gamma-ray burst jets

Relativistic jets associated with long/soft gamma-ray bursts are formed and initially propagate in the interior of the progenitor star. Because of the subsequent loss of their external pressure support after they cross the stellar surface, these flows can be modeled as moving around a corner. A strong steady-state rarefaction wave is formed, and the sideways expansion is accompanied by a rarefaction acceleration. We investigate the efficiency and the general characteristics of this mechanism by integrating the steady-state, special relativistic, magnetohydrodynamic equations, using a special set of partial exact solutions in planar geometry (r self-similar with respect to the "corner"). We also derive analytical approximate scalings in the ultrarelativistic cold/magnetized, and hydrodynamic limits. The mechanism is more effective in magnetized than in purely hydrodynamic flows. It substantially increases the Lorentz factor without much affecting the opening of the jet; the resulting values of their product can be much grater than unity, allowing for possible breaks in the afterglow light curves. These findings are similar to the ones from numerical simulations of axisymmetric jets by Komissarov et al and Tchekhovskoy et al, although in our approach we describe the rarefaction as a steady-state simple wave and self-consistently calculate the opening of the jet that corresponds to zero external pressure.Comment: 11 page

Applications of lean thinking: a briefing document

This report has been put together by the Health and Care Infrastructure Research and Innovation Centre (HaCIRIC) at the University of Salford for the Department of Health. The need for the report grew out of two main simple questions, o Is Lean applicable in sectors other than manufacturing? o Can the service delivery sector learn from the success of lean in manufacturing and realise the benefits of its implementation?The aim of the report is to list together examples of lean thinking as it is evidenced in the public and private service sector. Following a review of various sources a catalogue of evidence is put together in an organised manner which demonstrates that Lean principles and techniques, when applied rigorously and throughout an entire organization/unit, they can have a positive impact on productivity, cost, quality, and timely delivery of services

Microphysics in GRB central engine

We study the structure and evolution of the accreting plasma in gamma ray burst central engines. The models are based on the general relativistic MHD simulations. The nuclear equation of state adequate for dense and degenerate plasma, is incorporated to the numerical scheme instead of a simple polytropic EOS. Plasma is cooled by neutrinos and energy is extracted from the rotating BH by magnetic fields. We discuss our results in the frame of the observable GRBs, and speculate about the origin of variability in the GRB jet emission. We also discuss the possible contribution from the heavy elements synthesized in winds from GRB engines to the kilonova emission.Comment: To be published in the proceedings of the XII Multifrequency Behaviour of High Energy Cosmic Sources Workshop, 12-17 June 2017, Palermo, Ital

A lean way of design and production for healthcare construction projects

As a consequence of the lack of solid conceptual foundation, the project management concepts and techniques usually applied within the construction sector are fragmented and have proved to be incapable of solving the complex problems of design management. As a result, healthcare providers have become frustrated with the outcomes such as cost and schedule overruns, accidents, less than expected quality and inadequate functionality. However, an investigation of successful healthcare projects reveals that new approaches have been developed to tackle such problems. This study uses recent data based on six construction projects. The idea is demonstrate how successful projects are dealing with the integration between design, production, and operations, through an appropriate approach to the management of production systems. The paper aims to assist the different parties of the AEC industry to better understand how practices applied into design phase could support the efficiency in the management of production systems

Benefits realisation for healthcare

Following the emergent importance of benefits realisation applied to healthcare infrastructure and service development programs, HaCIRIC has undertaken a research initiative targeting the development of a robust and comprehensive Benefits Realisation (BeReal©) process. The resulting model is focusing on how benefits should be elicited at the initial strategic stages, and how benefits should be deployed, managed and traced along the lifecycle of a programme so their realisation contributes to successful health outcomes. Subsequently BeReal© aspires to be an appropriate method to drive and control the programme plan; providing tools and techniques for defining specific benefits. It also allows the measurement and evaluation of the extent to which those benefits are delivered. We have set ourselves the objective of identifying current best practices and demonstrate how to improve benefits realisation in healthcare infrastructure provision. The HaCIRIC team in active collaboration with leading industry partners have undertaken various case and comparator studies not only to define a business critical process but to set out an ideology which places benefits realisation at the heart of securing wholly integrated (collective) change. We believe that to deliver consistent high quality infrastructure and services within an ever changing investment model requires a different level of thinking and understanding towards benefits realisation. The challenge of answering community needs through intelligent investment in infrastructure is complex and demands a deeper and inclusive awareness and appreciation of how to deliver benefits and effectively allocate resources. The BeReal© initiative seeks to contribute methodologically and intends to help spending money intelligently, working with programme and project related stakeholders, securing that the best possible benefits are obtained for the overall healthcare communities. This report highlights selected performed initiatives and summarises BeReal© process’s major characteristics, covering far more than the follow-up of a competitive tendering process and of the development of a traditional business case. BeReal© copes with a detailed definition of changing activities, breakdown of (needs into) benefits that drive the investment, supports decision-making, proposes the development of controlling initiatives and suggests major awareness to the implementation of corrective actions. We seek to continue innovating, stimulate learning, contributing to an increase of health and care performance that properly answers to community needs and intelligently invests public and private resources