AN INVESTIGATION OF A NOVEL GAS-SOLID SEPARATOR FOR DOWNER REACTORS

Rapid gas-solid separation is a critical stage in many industrial applications, such as fluid k *- lytic cracking (FCC), heavy oil upgrading, and biomass pyrolysis. In these applications, act gases must be separated quickly and efficiently from catalyst or heat-bearing particles to srminate cracking reactions. Several rapid separation devices have been proposed to achieve sse demands. However, most proposed designs were intended for FCC processes. Very few gas-solid separators have been proposed specifically for biomass pyrolysis. A novel gas-solid separator for biomass pyrolysis in a downer reactor is investigated in this jesis. An experimental study is performed to identify important separator geometry and operating conditions. Computational fluid dynamics (CFD) is used to gain insight into the two- shase flow structure in the separator. The numerical results are coupled with an original ^experimental technique for measuring the particle-wall restitution coefficient to select !appropriate materials for the separator’s internal surface

Testing for simplification in spatial models

Data collected on a rectangular lattice occur frequently in many areas such as field trials, geostatistics, remotely sensed data, and image analysis. Models for the spatial process often make simplifying assumptions, including axial symmetry and separability. We consider methods for testing these assumptions and compare tests based on sample covariances, tests based on the sample spectrum, and model-based tests

Process studies of odour emissions from effluent ponds using machine-based odour measurement

Replicable experimental studies using a novel experimental facility and a machine-based odour quantification technique were conducted to demonstrate the relationship between odour emission rates and pond loading rates. The odour quantification technique consisted of an electronic nose, AromaScan A32S, and an artificial neural network. Odour concentrations determined by olfactometry were used along with the AromaScan responses to train the artificial neural network. The trained network was able to predict the odour emission rates for the test data with a correlation coefficient of 0.98. Time averaged odour emission rates predicted by the machine-based odour quantification technique, were strongly correlated with volatile solids loading rate, demonstrating the increased magnitude of emissions from a heavily loaded effluent pond. However, it was not possible to obtain the same relationship between volatile solids loading rates and odour emission rates from the individual data. It is concluded that taking a limited number of odour samples over a short period is unlikely to provide a representative rate of odour emissions from an effluent pond. A continuous odour monitoring instrument will be required for that more demanding task

A spatiotemporal perspective on empowerment

The complex and dynamic nature of project environments presents both opportunities and challenges for the empowerment of individuals and teams. Yet, empowerment is a complex concept in its own right, taking on multiple forms across people, is contextually embedded and shifts over time. As research on empowerment in projects continues to grow, pertinent questions are emerging aimed at promoting the growth of empowerment theory and its applicability in practice. For example, how do organizations empower employees at different levels and still be able to achieve goal congruence across the organization?; how does empowerment manifest itself across project phases?; and how does empowerment manifest across co-located or geographically/physically spaced individuals on the same or different projects/teams across the same organization? The multiplicity and dynamism of empowerment in projects across three aspects - space, time and levels, and their intersections are examined within the context of the complex, dynamic and uncertain operational realities of projects. It is argued that such a spatiotemporal agenda is better understood through the lens of chaos and complexity theory, a perspective that reveals the way in which empowerment is intertwined with other managerial interventions and business strategies for the successful delivery of projects

Probing crystallisation of a fluoro-apatite - mullite system using neutron diffraction

Real-time small angle neutron scattering and wide angle neutron scattering studies were undertaken concurrently on a glass ionomer of nominal composition 4.5(SiO2)-3(Al2O3)-1.5(P2O5)-3(CaO)-2(CaF2). Neutron studies were conducted as a function of temperature to investigate the crystallisation process. No amorphous phase separation was observed at room temperature and the onset of crystallisation was found to occur at 650°C, which is 90°C lower than previously reported. The first crystalline phase observed corresponded to fluorapatite; it was only upon further heating was the mullite phase became present. The crystallite size at 650°C was found to be ~115Å and the result was consistent across all measurements

Dynamics of empowerment in projects

Empowerment varies depending on the targeted population, the targeted setting and also fluctuates across time. These perspectives have rarely been examined simultaneously and no theoretical framework has as yet articulated such an integrative perspective in any specific setting. The complex and dynamic nature of the project environment and the project life cycle in particular have significant implications for understanding how empowerment manifests in projects. To better understand the implications of empowerment’s multifaceted nature in a complex setting such as the project environment, we invoke complexity paradigm as a theoretical lens that is well positioned to help capture the essence of empowerment. From this theoretical framework, the true nature of how empowerment can intertwine with the complex and uncertain project context can be captured and described from the perspective of the workforce or actors engaged in the creation, execution, and closure of the project. Three preeminent questions that can aid this line of enquiry emerge from this review; how can organisations empower employees at different levels simultaneously within the same project team and still achieve goal congruence?; how does the changing nature of the project life cycle impact on employee empowerment experiences?; and what does the multidimensional perspective on empowerment add to our knowledge of empowerment in organisations

Understanding the effect of transformation leadership behaviour of middle managers on innovation in project based organisations

The purpose of this study was to investigate the role of transformational leadership behaviour of middle managers on innovation. It followed a quantitative data collection and analysis to examine the relationship between transformational leadership on climate for innovation, innovation championing behaviour and project performance. In-depth interviews were held with 13 members of staff selected from different parts of the company. In addition a focus group discussion was held with Technical Directors in order to develop a deeper understanding of the processes by which middle managers influence innovation in project based professional services organisations. Findings from the study suggest that middle managers’ transformational leadership behaviour impacts project outcomes by helping to develop a climate for innovation and influencing the championing behaviour of their staff. Notwithstanding the fact that the study was based on a single UK based professional services firm, the findings adds to our understanding of the role of middle level leadership in project environment in facilitating innovation and answers the call for more qualitative approaches to understanding the impact of leaders in project based organisations. The findings also highlight the significant impact middle managers can have on innovation and ultimately project performance contrary to the previous publications that advanced a more negative view of the role of middle managers in organisations

The Structure of Screening in QED

The possibility of constructing charged particles in gauge theories has long been the subject of debate. In the context of QED we have shown how to construct operators which have a particle description. In this paper we further support this programme by showing how the screening interactions arise between these charges. Unexpectedly we see that there are two different gauge invariant contributions with opposite signs. Their difference gives the expected result.Comment: 8 pages, LaTe

Complete two-loop effective potential approximation to the lightest Higgs scalar boson mass in supersymmetry

I present a method for accurately calculating the pole mass of the lightest Higgs scalar boson in supersymmetric extensions of the Standard Model, using a mass-independent renormalization scheme. The Higgs scalar self-energies are approximated by supplementing the exact one-loop results with the second derivatives of the complete two-loop effective potential in Landau gauge. I discuss the dependence of this approximation on the choice of renormalization scale, and note the existence of particularly poor choices which fortunately can be easily identified and avoided. For typical input parameters, the variation in the calculated Higgs mass over a wide range of renormalization scales is found to be of order a few hundred MeV or less, and is significantly improved over previous approximations.Comment: 5 pages, 1 figure. References added, sample test model parameters listed, minor wording change