Heat transfer to a resonant pulsating air stream in a pipe

The effect on convective heat transfer of resonant, longitudinal oscillations superimposed on a turbulent mean flow in a pipe has been investigated relative to the equivalent steady flow. Theoretically it is shown that the effect of acoustic streaming velocities is negligible for the range of pulsation parameters, but that the oscillating velocity can generate changes in the time-mean flow diffusivity - the change in mean diffusivity can only be predicted if quasi-steady pulsations are assumed. Heat transfer coefficients for the mean flow are evaluated from the Energy equation, for fully established conditions, assuming quasi-steady oscillations. It is proposed that a frequency factor can be derived to relate experimental heat transfer to the quasi-steady predictions, and that the factor would be a function of Strouhal number only. Local heat transfer coefficients were measured for a constant heat flux supply to an oscillating air flow in a pipe. The pulsations were generated by a siren. It was shown that the centre-line velocity amplitudes could be predicted from inviscid flow theory using a mean velocity of sound. The range of the major parameters was: Diraensionless pulsation velocity 0.3 < B < 5 Strouhal number 0.5 < S < 10 Reynolds number 14,300 < Red < 31,250. For fully developed flow, the experimental results were related to the corresponding quasi-steady predictions by a function of Strouhal number. It was shown that the changes in heat transfer were due to changes in the mean diffusivity generated by the acoustic velocity. For a defined range of pulsation parameters, it is possible to predict local heat transfer coefficients under fully established conditions for a pulsating flow from the empirical frequency correction factor applied to the theoretical quasi-steady predictions

Developing sexual competence? Exploring strategies for the provision of effective sexualities and relationships education

School-based sexualities and relationships education (SRE) offers one of the most promising means of improving young people's sexual health through developing 'sexual competence'. In the absence of evidence on whether the term holds the same meanings for young people and adults (e.g. teachers, researchers, policy-makers), the paper explores 'adult' notions of sexual competence as construed in research data and alluded to in UK Government guidance on SRE, then draws on empirical research with young people on factors that affect the contexts, motivations and outcomes of sexual encounters, and therefore have implications for sexual competence. These data from young people also challenge more traditional approaches to sexualities education in highlighting disjunctions between the content of school-based input and their reported sexual experience. The paper concludes by considering the implications of these insights for developing a shared notion of what SRE is trying to achieve and suggestions for recognition in the content and approaches to SRE.</p

Exchange Narrowing Effects in the EPR Linewidth of Gd Diluted in Ce Compounds

Anomalous thermal behavior on the EPR linewidths of Gd impurities diluted in Ce compounds has been observed. In metals, the local magnetic moment EPR linewidth, \Delta H, is expected to increase linearly with the temperature. In contrast, in Ce_{x}La_{1-x}Os_{2} the Gd EPR spectra show a nonlinear increase. In this work, the mechanisms that are responsible for the thermal behavior of the EPR lines in Ce_{x}La_{1-x}Os_{2} are examined. We show that the exchange interaction between the local magnetic moments and the conduction electrons are responsible for the narrowing of the spectra at low temperatures. At high temperatures, the contribution to the linewidth of the exchange interaction between the local magnetic moments and the $Ce$ ions has an exponential dependence on the excitation energy of the intermediate valent ions. A complete fitting of the EPR spectra for powdered samples is obtained.Comment: 11 pages, 1 figur

Orbital Kondo Effect in Cex_xLa1−x_{1-x}B6_6: Scaling Analysis

Peculiarity of the Kondo effect in Ce$_x$La$_{1-x}$B$_6$ is investigated on the basis of the scaling equations up to third order. For the case where the $f^1$-$f^2$ charge fluctuation enters in addition to the $f^1$-$f^0$ one, the effective exchange interaction becomes anisotropic with respect to the orbital pseudospins which represent the two different orbitals in the $\Gamma_8$ ground state. Because of different characteristic energies for electric and magnetic tensors, scaling with the single Kondo temperature does not apply to physical quantities such as the resistivity and magnetic susceptibility. Possibility of a bizzare phase is pointed out where the RKKY interaction leads to the spin ordering without orbital ordering. This phase serves as a candidate of the phase IV which is observed to be isotropic magnetically.Comment: 10 pages, 4 eps figures, submitted to PR

Exposing the myth of the 1:5:200 ratio relating initial cost, maintenance and staffing costs of office buildings

In an attempt to focus clients' minds on the importance of considering the construction and maintenance costs of a commercial office building (both as a factor in staff productivity and as a fraction of lifetime staff costs) there is an often-quoted ratio of costs of 1:5:200, where for every one pound spent on construction cost, five are spent on maintenance and building operating costs and 200 on staffing and business operating costs. This seems to stem from a paper published by the Royal Academy of Engineering, in which no data is given and no derivation or defence of the ratio appears. The accompanying belief that higher quality design and construction increases staff productivity, and simultaneously reduces maintenance costs, how ever laudable, appears unsupported by research, and carries all the hallmarks of an "urban myth". In tracking down data about real buildings, a more realistic ratio appears to depend on a huge variety of variables, as well as the definition of the number of "lifetime" years. The ill-defined origins of the original ratio (1:5:200) describing these variables have made replication impossible. However, by using published sources of data, we have found that for three office buildings, a more realistic ratio is 1:0.4:12. As there is nothing in the public domain about what comprised the original research that gave rise to 1:5:200, it is not possible to make a true comparison between these new calculations and the originals. Clients and construction professionals stand to be misled because the popularity and widespread use of the wrong ratio appears to be mis-informing important investment and policy decisions

'Selling it as a holistic health provision and not just about condoms ?' Sexual health services in school settings: current models and their relationship with sex and relationships education policy and provision

In this article we discuss the findings from a recent study of UK policy and practice in relation to sexual health services for young people, based in - or closely linked with - schools. This study formed part of a larger project, completed in 2009, which also included a systematic review of international research. The findings discussed in this paper are based on analyses of interviews with 51 service managers and questionnaire returns from 205 school nurses. Four themes are discussed. First, we found three main service permutations, in a context of very diverse and uneven implementation. Second, we identified factors within the school context that shaped and often constrained service provision; some of these also have implications for sex and relationships education (SRE). Third, we found contrasting approaches to the relationship between SRE input and sexual health provision. Fourth, we identified some specific barriers that need to be addressed in order to develop 'young people friendly' services in the school context. The relative autonomy available to school head teachers and governors can represent an obstacle to service provision - and inter-professional collaboration - in a climate where, in many schools, there is still considerable ambivalence about discussing 'sex' openly. In conclusion, we identify areas worthy of further research and development, in order to address some obstacles to sexual health service and SRE provision in schools

Well-being and citizenship in urban Nigeria

Well-being is increasingly used as a criterion to measure development outcomes, in the light of the now established critique of income as a satisfactory measure (UNDP, 1990). The aim of the key development policy document in Nigeria, Nigerian Vision 20:2020, is to improve the well-being of Nigerians. However, as well-being is an emerging and contested concept, this report explores how the well-being of urban citizens is understood specifically in Nigeria, and identifies the key issues for urban well-being as expressed by a selection of key stakeholders in Nigerian society. This is an important task in the Nigerian context, which is characterised by impressive and sustained growth rates juxtaposed alongside increasing rates of both income poverty and subjective poverty. This study analyses the discourses and views of 45 urban stakeholders strategically positioned at different levels of Nigerian society, as well as existing literature and documents. Based on White’s (2010) framework for the analysis of well-being and contemporary conceptualisations of citizenship, the analysis reveals three main trends affecting urban well-being: (i) rapid demographic changes that make it difficult for government to respond with adequate planning and interventions; (ii) a number of governance issues, particularly regarding power distribution, lack of city-level governance and the role of the state; (iii) the existence of stratified citizenship characterised by unequal access to services and rights based on socio-spatial discrimination and notions of indigeneity. Electricity, congestion, housing, youth unemployment, security and health are a number of key areas which were raised during interviews in which the inadequate and unequal provision of goods and services, underpinned by these three trends, affect urban well-being. An analysis of stakeholders’ conceptualisations of well-being showed how it is viewed in terms of basic needs to be achieved through economic growth, and how well-being is itself considered fundamental for productivity. Well-being was also understood through the broad notion of security, emphasising different dimensions beyond the material aspect. Finally, another understanding of well-being was as ‘social order’, a problematic idea at the root of existing and proposed policies. Policies for urban well-being present three characteristics: (i) policies are underpinned by the notion of restoring social order, with chaos and disorder (often associated with informality) seen as a cause of ill-being; (ii) the prominence of middle-class concerns and the exclusion of non- indigenes and those living in poverty; (iii) government being seen as a provider of the enabling environment and infrastructure needed for private sector actors to deliver economic growth which purportedly lead to improved well-being. These characteristics were present in a number of policy concerns raised by stakeholders, including: decongestion policies; transport and road infrastructure; social security for unemployed; education and food security. A generally negative view of urbanisation emerges with a strong emphasis on stopping rural-urban migration as a way to halt urban growth. The research has highlighted a range of very important citizenship practices to deliver goods and services essential to citizens’ well-being. These practices reveal the importance of autonomous collective action in the achievement of well-being. They also show the role that income levels and other social identities such as indigeneity play in such processes. While these processes mostly focus on the delivery of goods and services, in the context of a democratic government still in transition, they also become a platform for voice and the claiming of rights. A key problem that emerges and requires further research is the issue of the inappropriate planning taking place, which serves particular interests and further entrenches inequalities. The report encourages an open discussion on the current urban governance arrangements in Nigeria, particularly the division of roles between different tiers of government, and also on how city-level governance may enable citizenship practices that complement public interventions. The report also questions the effectiveness of strategies for urban well- being solely focused on creating an enabling environment for investment and economic growth to address the concerns of the large majority of low- income residents. In particular, the report indicates that policies often exclude the urban poor and non-indigenes and the removal of these discriminations is necessary for the achievement of well-being for all in Nigerian cities and towns. Finally the report acknowledges the importance of the state in providing or regulating the provision of a number of goods, services and infrastructure, whose provision in urban areas is still inadequate

Building governance and energy efficiency: Mapping the interdisciplinary challenge

Improving the energy efficiency of multi-owned properties (MoPs)—commonly known as apartment or condominium buildings—is central to the achievement of European energy targets. However, little work to date has focused on how to facilitate retrofit in this context. Drawing on interdisciplinary Social Sciences and Humanities expertise in academia, policy and practice, this chapter posits that decision-making processes within MoPs might provide a key to the retrofit challenge. Existing theories or models of decision-making, applied in the MoP context, might help to explain how collective retrofit decisions are taken—or overlooked. Insights from case studies and practitioners are also key. Theories of change might then be employed to develop strategies to facilitate positive retrofit decisions. The chapter maps the issues and sets an agenda for further interdisciplinary research in this novel area