Fully coupled, hygro-thermo-mechanical sensitivity analysis of a pre-stressed concrete pressure vessel

Following a recent world wide resurgence in the desire to build and operate nuclear power stations as a response to rising energy demands and global plans to reduce carbon emissions, and in the light of recent events such as those at the Fukushima Dai-ichi nuclear power plant in Japan, which have raised questions of safety, this work has investigated the long term behaviour of concrete nuclear power plant structures.<p></p> A case example of a typical pre-stressed concrete pressure vessel (PCPV), generically similar to several presently in operation in the UK was considered and investigations were made with regard to the extended operation of existing plants beyond their originally planned for operational life spans, and with regard to the construction of new build plants.<p></p> Extensive analyses have been carried out using a fully coupled hygro-thermo-mechanical (HTM) model for concrete. Analyses were initially conducted to determine the current state of a typical PCPV after 33+ years of operation. Parametric and sensitivity studies were then carried out to determine the influence of certain, less well characterised concrete material properties (porosity, moisture content, permeability and thermal conductivity). Further studies investigated the effects of changes to operational conditions including planned and unplanned thermal events.<p></p> As well as demonstrating the capabilities and usefulness of the HTM model in the analysis of such problems, it has been shown that an understanding of the long-term behaviour of these safety–critical structures in response to variations in material properties and loading conditions is extremely important and that further detailed analysis should be conducted in order to provide a rational assessment for life extension.<p></p> It was shown that changes to the operating procedures led to only minor changes in the behaviour of the structure over its life time, but that unplanned thermal excursions, like those seen at the Fukushima Dai-ichi plant could have more significant effects on the concrete structures.<p></p&gt

Modelling of transport processes in concrete exposed to elevated temperatures – An alternative formulation for sorption isotherms

There is a significant need to understand, analyse and assess moisture transport in cementitious materials exposed to elevated temperatures in order to confidently predict the behaviour and ultimately the development of damage in safety critical applications such as nuclear reactor vessels, structures exposed to fire and well bore grouts. In view of this need a rigorous and robust formulation to describe water retention curves (sorption isotherms) as a function of temperature based on the evolution of physical parameters is presented. The model formulation is successfully validated against independent sets of experimental data up to temperatures of 80 °C. It is then further validated under isothermal drying conditions and then high temperature conditions through the numerical reproduction of laboratory experiments following implementation in a fully coupled hygro-thermo-mechanical finite element model. The new formulation is found to work well under a variety of conditions in a variety of cementitious material types

Simulation of pyroshock environments using a tunable resonant fixture

Disclosed are a method and apparatus for simulating pyrotechnic shock for the purpose of qualifying electronic components for use in weapons, satellite, and aerospace applications. According to the invention, a single resonant bar fixture has an adjustable resonant frequency in order to exhibit a desired shock response spectrum upon mechanical impact. The invention eliminates the need for availability of a large number of different fixtures, capable of exhibiting a range of shock response characteristics, in favor of a single tunable system

Potential of relative humidity as a proxy of air temperature in developing passive and adaptive building fa\ue7ades with bio-based responsive materials

There has been significant development in thermo-responsive materials for drug delivery and bio-medical use; some are bio-based. However, the use of thermo-responsive bio-based materials in the built environment, especially on the building fa\ue7ade, is almost non-existent due to complexities including difficulties manufacturing in bulk, cost and durability to weathering. On the other hand, humidity-responsive materials such as wood are abundant and are used in buildings globally. Furthermore, new bio-based humidity-responsive materials such as bacterial cellulose (BC) and natural fibres have the potential for building applications. In this study, we hypothesised that if there was a relationship between the relative humidity and air temperature in a location, humidity-responsive materials could be used to develop passive and adaptive building fa\ue7ades, which would indirectly respond to temperature. Here, we selected two sites (New Delhi, India and Newcastle upon Tyne, UK) with temperate climates — according to the K\uf6ppen-Geiger system— to analyse the relationship between relative humidity and air temperature from 37 years (1985-2022) of weather data and typical meteorological year (TMY) climate data for 2004-2018. This relationship assessment used the Pearson correlation (coefficient and p-value) analysis. Our results showed a strong and statistically significant negative correlation between the relative humidity and air temperature in all months in 37 years in New Delhi, with the strongest correlation in the summer and monsoon months. However, the correlation was strong only in some summer months for Newcastle upon Tyne. We concluded that humidity-responsive bio-based materials have the potential to be used to actuate passive and adaptive building fa\ue7ades in New Delhi (for all-year-round use) and Newcastle (only during summer), which respond indirectly to external temperature

Bio-jaali: Passive building skin with mycelium for climate change adaptation to extreme heat

Climate change induced global warming and frequent extreme heat events have become common recently, increasing the ownership and operation of active cooling, particularly in cities and megacities. To reduce the dependency on active cooling, in this study, we aimed to re-design ‘Jaali’— perforated screens made of bricks and sandstones to cool the incoming air inspired by historical building use— with bio-based materials such as mycelium. We hypothesised that ‘Bio-jaali’ would ventilate and reduce the indoor temperature reducing energy demand for cooling. For the climatic context, we selected the temperate climate of New Delhi. We used climatic data analysis and performance-based dynamic environmental simulations with Designbuilder and Energy Plus to evaluate the effect of Bio-jaali on the indoor operative temperature in a single-zone naturally ventilated indoor office space. The simulation results showed sandstone Jaali reduced the annual average indoor operative temperature by 5.2%, whereas Bio-jaali were able to provide a reduction of 3.0% compared to the base case. Furthermore, the seasonal analysis showed that Bio-jaali reduced the summer indoor operating temperature by decreasing heat gain from outdoor heat, particularly during daytime and increased indoor temperature during winter by reducing heat loss, demonstrating its potential for year-round usage

Scaling law in the Standard Map critical function. Interpolating hamiltonian and frequency map analysis

We study the behaviour of the Standard map critical function in a neighbourhood of a fixed resonance, that is the scaling law at the fixed resonance. We prove that for the fundamental resonance the scaling law is linear. We show numerical evidence that for the other resonances $p/q$, $q \geq 2$, $p \neq 0$ and $p$ and $q$ relatively prime, the scaling law follows a power--law with exponent $1/q$.Comment: AMS-LaTeX2e, 29 pages with 8 figures, submitted to Nonlinearit

Re-Inventing Public Education:The New Role of Knowledge in Education Policy-Making

This article focuses on the changing role of knowledge in education policy making within the knowledge society. Through an examination of key policy texts, the Scottish case of Integrated Children Services provision is used to exemplify this new trend. We discuss the ways in which knowledge is being used in order to re-configure education as part of a range of public services designed to meet individuals' needs. This, we argue, has led to a 'scientization' of education governance where it is only knowledge, closely intertwined with action (expressed as 'measures') that can reveal problems and shape solutions. The article concludes by highlighting the key role of knowledge policy and governance in orienting education policy making through a re-invention of the public role of education

Factors influencing quality of life following lower limb amputation for peripheral arterial occlusive disease: a systematic review of the literature

Background: The majority of lower limb amputations are undertaken in people with peripheral arterial occlusive disease,\ud and approximately 50% have diabetes. Quality of life is an important outcome in lower limb amputations; little is known\ud about what influences it, and therefore how to improve it.\ud Objectives: The aim of this systematic review was to identify the factors that influence quality of life after lower limb\ud amputation for peripheral arterial occlusive disease.\ud Methods: MEDLINE, EMBASE, CINAHL, PsycINFO, Web of Science and Cochrane databases were searched to identify\ud articles that quantitatively measured quality of life in those with a lower limb amputation for peripheral arterial occlusive\ud disease. Articles were quality assessed by two assessors, evidence tables summarised each article and a narrative\ud synthesis was performed.\ud Study design: Systematic review.\ud Results: Twelve articles were included. Study designs and outcome measures used varied. Quality assessment scores\ud ranged from 36% to 92%. The ability to walk successfully with a prosthesis had the greatest positive impact on quality\ud of life. A trans-femoral amputation was negatively associated with quality of life due to increased difficulty in walking\ud with a prosthesis. Other factors such as older age, being male, longer time since amputation, level of social support and\ud presence of diabetes also negatively affected quality of life.\ud Conclusion: Being able to walk with a prosthesis is of primary importance to improve quality of life for people with lower\ud limb amputation due to peripheral arterial occlusive disease. To further understand and improve the quality of life of this\ud population, there is a need for more prospective longitudinal studies, with a standardised outcome measure

Scaling of the Critical Function for the Standard Map: Some Numerical Results

The behavior of the critical function for the breakdown of the homotopically non-trivial invariant (KAM) curves for the standard map, as the rotation number tends to a rational number, is investigated using a version of Greene's residue criterion. The results are compared to the analogous ones for the radius of convergence of the Lindstedt series, in which case rigorous theorems have been proved. The conjectured interpolation of the critical function in terms of the Bryuno function is discussed.Comment: 26 pages, 3 figures, 13 table