Numerical Comparison of the Drag Models of Granular Flows Applied to the Fast Pyrolysis of Biomass

The paper presents a comparison between the different drag models for granular flows developed in the literature and the effect of each one of them on the fast pyrolysis of wood. The process takes place on an 100 g/h lab scale bubbling fluidized bed reactor located at Aston University. FLUENT 6.3 is used as the modeling framework of the fluidized bed hydrodynamics, while the fast pyrolysis of the discrete wood particles is incorporated as an external user defined function (UDF) hooked to FLUENT’s main code structure. Three different drag models for granular flows are compared, namely the Gidaspow, Syamlal O’Brien, and Wen-Yu, already incorporated in FLUENT’s main code, and their impact on particle trajectory, heat transfer, degradation rate, product yields, and char residence time is quantified. The Eulerian approach is used to model the bubbling behavior of the sand, which is treated as a continuum. Biomass reaction kinetics is modeled according to the literature using a two-stage, semiglobal model that takes into account secondary reactions.

‘Here come “Chelsea” of Sweden’:Djurgården football club on tour in apartheid South Africa

In this article we argue that while apartheid, boycotts and South African sport have received significant coverage and focus, this has primarily been restricted to Britain and former white colonies of the Commonwealth such as Australia and New Zealand. In addition, sports such as cricket and rugby receive most attention. We argue that it is useful to consider other countries and sports engaged in apartheid South Africa. We consider Swedish engagement with apartheid South Africa and focus the case study of our analysis on the tour by champions Djurgården to the country in 1955. The tourists received favourable and widespread support in South Africa and Sweden. Yet towards the end of the tour sections of the Swedish press asked critical and probing questions of the club's tour to South Africa. We contend that the tour can be viewed as naïve and apolitical and in a similar vein to the organization of Swedish sports at that time. Only after the intensification of suppression of opposition to apartheid in South Africa from the 1960s onwards do we see a change in stance on the part of Swedish sports authorities. © 2013 © 2013 The British Society of Sports History.

Range of self-tests available to buy in the United Kingdom: an Internet survey

We aimed to describe the availability in the United Kingdom of self-tests that are used to diagnose or screen for conditions without involving a health professional. A systematic Internet search identified 104 unique self-tests related to 24 named conditions including cancers, chronic conditions and infections. These self-tests require various samples including blood obtained using a lancet. The samples are processed at home with results available in minutes or sent to a laboratory for processing with results returned to the individual by e-mail or post. Prices per self-test and condition range from <1 pound to 76 pound. Self-tests are readily available, and further work is needed to assess their impact.

Addressing the project implementation challenges in the Saudi Arabian power supply industry: an investigative approach towards improving project delivery

For many decades, the Kingdom of Saudi Arabia has been widely known for being a reliable oil exporter. This fact, however, has not exempted it from facing significant domestic energy challenges. One of the most pressing of these challenges involves bridging the widening electricity supply-demand gap where, currently, the demand is growing at a very fast rate. One crucial means to address this challenge is through delivering power supply projects with maximum efficiency. Project delivery delay, however, is not uncommon in this highly capital-intensive industry, indicating electricity supplies are not coping with the demand increases. To provide a deeper insight into the challenges of project implementation and efficient practice, this research adopts a pragmatic approach by triangulating literature, questionnaires and semi-structured interviews. The research was conducted in the Saudi Arabian power supply industry – Western Operating Area. A total of 105 usable questionnaires were collected, and 28 recorded, semi-structured interviews were conducted, analysed and synthesised to produce a conceptual model of what constitutes the project implementation challenges in the investigated industry. This was achieved by conducting a comprehensive ranking analysis applied to all 58 identified and surveyed factors which, according to project practitioners in the investigated industry, contribute to project delay. 28 of these project delay factors were selected as the "most important" ones. Factor Analysis was employed to structure these 28 most important project delay factors into the following meaningful set of 7 project implementation challenges: Saudi Electricity Company's contractual commitments, Saudi Electricity Company's communication and coordination effectiveness, contractors' project planning and project control effectiveness, consultant-related aspects, manpower challenges and material uncertainties, Saudi Electricity Company's tendering system, and lack of project requirements clarity. The study has implications for industry policy in that it provides a coherent assessment of the key project stakeholders' central problems. From this analysis, pragmatic recommendations are proposed that, if enacted, will minimise the significance of the identified problems on future project outcomes, thus helping to ensure the electricity supply-demand gap is diminished.