Bradford Scholars is the University of Bradford online research archive. Access is free to anyone interested in research being conducted at Bradford. In the repository you will find a range of materials from journal articles and conference papers to research reports and theses.

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  • Steam consumption minimization using genetic algorithm optimization method: an industrial case study

    Alabdulkarem, A.; Rahmanian, Nejat (2020)
    Condensate stabilization is a process where hydrocarbon condensate recovered from natural gas reservoirs is processed to meet the required storage, transportation, and export specifications. The process involves stabilizing of hydrocarbon liquid by separation of light hydrocarbon such as methane from the heavier hydrocarbon constituents such as propane. An industrial scale back-up condensate stabilization unit was simulated using Aspen HYSYS software and validated with the plant data. The separation process consumes significant amount of energy in form of steam. The objectives of the paper are to find the minimum steam consumption of the process and conduct sensitivity and exergy analyses on the process. The minimum steam consumption was found using genetic algorithm optimization method for both winter and summer conditions. The optimization was carried out using MATLAB software coupled with Aspen HYSYS software. The optimization involves six design variables and four constraints, such that realistic results are achieved. The results of the optimization show that savings in steam consumption is 34% as compared to the baseline process while maintaining the desired specifications. The effect of natural gas feed temperature has been investigated. The results show that steam consumption is reduced by 46% when the natural gas feed temperature changes from 17.7 to 32.7°C. Exergy analysis shows that exergy destruction of the optimized process is 37% less than the baseline process.
  • Towards a practice theory of goal setting: assessing the theoretical goal-setting of a leprosy organisation in Nigeria

    Ogbeiwi, Osahon (2020)
    Goal-setting is indispensable for effective healthcare management. Yet, literature evidence suggests many organisations worldwide do not know how to formulate ‘SMART’ goals. Evidence of how existing theories work in practice is scarce, and the practices in low-income countries are unknown. Therefore, this research explored how leprosy project goals were formulated to describe the theoretical practice framework of A leprosy-focused organisation in Nigeria. Using a case-study design, ten managers were interviewed individually concerning their goal-setting knowledge, experience and perspective; and documented goals of six projects were reviewed. A five-step constructionist thematic data analysis generated eleven theoretical frameworks from the concepts of the emergent core themes of ‘stakeholders’, ‘strategies’ and ‘statements.’ Further theorisation reduced them to one general framework. This revealed organisational goal-setting practice as a four-stage centre-led, top-down, beneficiary-focused and problem-based process. The stages were national preparation, baseline needs-survey, centralised goal formulation and nationalised planning. The outcome was the formulation of assigned, ‘non-SMART’ objective statements, which are then used for planning projects. Other theoretical models constructed included a Goal Effects Cycle, ‘SMARTA’ goal attributes and hierarchical criteria for differentiating goal-types. A theory developed from the goal-setting practice postulates that: ‘Assigned non-SMART goal formulation directly results from centralised goal-setting practice and is the predictor of unrealistic project planning.’ Therefore, I propose that goal statements will be ‘SMARTA’ and plans, more realistic and relevant if goal-setting is done collaboratively by all stakeholders at all stages of the process. Also, ‘Change-Beneficiary-Indicator-Target-Timeframe’ and ‘Change-Beneficiary-Location-Timeframe’ frameworks are recommended as templates for writing SMART objectives and aims respectively.
  • Equivalence classes of coherent projectors in a Hilbert space with prime dimension: Q functions and their Gini index

    Vourdas, Apostolos (2020-05)
    Coherent subspaces spanned by a finite number of coherent states are introduced, in a quantum system with Hilbert space that has odd prime dimension d. The set of all coherent subspaces is partitioned into equivalence classes, with d 2 subspaces in each class. The corresponding coherent projectors within an equivalence class, have the 'closure under displacements property' and also resolve the identity. Different equivalence classes provide different granularisation of the Hilbert space, and they form a partial order 'coarser' (and 'finer'). In the case of a two-dimensional coherent subspace spanned by two coherent states, the corresponding projector (of rank 2) is different than the sum of the two projectors to the subspaces related to each of the two coherent states. We quantify this with 'non-addditivity operators' which are a measure of quantum interference in phase space, and also of the non-commutativity of the projectors. Generalized Q and P functions of density matrices, which are based on coherent projectors in a given equivalence class, are introduced. Analogues of the Lorenz values and the Gini index (which are popular quantities in mathematical economics) are used here to quantify the inequality in the distribution of the Q function of a quantum state, within the granular structure of the Hilbert space. A comparison is made between Lorenz values and the Gini index for the cases of coarse and also fine granularisation of the Hilbert space. Lorenz values require an ordering of the d 2 values of the Q function of a density matrix, and this leads to the ranking permutation of a density matrix, and to comonotonic density matrices (which have the same ranking permutation). The Lorenz values are a superadditive function and the Gini index is a subadditive function (they are both additive quantities for comonotonic density matrices). Various examples demonstrate these ideas.
  • Citizens' continuous use of eGovernment services: The role of self-efficacy, outcome expectations and satisfaction

    Alruwaie, M.; El-Haddadeh, R.; Weerakkody, Vishanth J.P. (2020-07)
    The continuous use of eGovernment services is a de facto for its prosperity and success. A generalised sense of citizens' self-efficacy, expectations, and satisfaction offer opportunities for governments to further retain needed engagements. This study examines the factors influencing citizens' continuance use of eGovernment services. Through the integration of Social Cognitive Theory, Expectation Confirmation Theory, DeLone and McLean IS success model, and E-S-QUAL, a survey of 471 citizens in the UK, engaging in online public services, found that prior experience, social influence, information quality, and service quality, personal outcome expectation, and satisfaction, are significant predictors of citizens' intention to use eGovernment, when they are regulated, through citizens' self-efficacy. The present study extends the roles of pre-adoption and post-adoption by offering a self-regulating process. Therefore, it demonstrates how critical it is for the government's leaders to understand the patterns of the long-term process for electronic systems continually.
  • Lotus-leaf inspired surfaces: hydrophobicity evolution of replicas due to mechanical cleaning and mold wear

    Romano, J-M.; Garcia-Giron, A.; Penchev, P.; Gulcur, Mert; Whiteside, Benjamin R.; Dimov, S. (2020-03)
    Inspired from the low wetting properties of Lotus leaves, the fabrication of dual micro/nano-scale topographies is of interest to many applications. In this research, superhydrophobic surfaces are fabricated by a process chain combining ultrashort pulsed laser texturing of steel inserts and injection moulding to produce textured polypropylene parts. This manufacturing route is very promising and could be economically viable for mass production of polymeric parts with superhydrophobic properties. However, surface damages, such as wear and abrasion phenomena, can be detrimental to the attractive wetting properties of replicated textured surfaces. Therefore, the final product lifespan is investigated by employing mechanical cleaning of textured polypropylene surfaces with multipurpose cloths following the ASTM D3450 standard. Secondly, the surface damage of replication masters after 350 injection moulding cycles with glass-fiber reinforced polypropylene, especially to intensify mould wear, was investigated. In both cases, the degradation of the dual-scale surface textures had a clear impact on surface topography of the replicas and thus on their wetting properties, too.

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