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Polymerisation of flame retardant organophosphorus and organo-inorganic hybrid coatings on polymeric surfaces
No full textPolymers are widely used across the globe in applications ranging from construction to biomedical, with increasing usage as time progresses. However, despite their prevalence polymers can be highly flammable materials, and though this may be combatted with the use of flame retardant additives, the additives themselves may have a detrimental effect on other properties of a polymeric material such as its aesthetics or structural integrity. One solution to this is the use of flame retardant coatings which are applied to the surface of a polymer, instead of additives which are incorporated into the polymer structure. Due to their surface application, flame retardant coatings will not affect the structure and thus the properties of the underlying polymer.In this PhD, a novel poly(vinyl phosphonic acid) (PVPA) based flame retardant coating was synthesised and characterised using Fourier Transform Infra-Red spectroscopy (FTIR), then tested as a flame retardant coating for both glass fibre reinforced epoxy (GRE) and poly(methylmethacrylate) (PMMA) under a cone calorimeter. The PVPA based flame retardant coating showed an impressive degree of flame retardance, lowering the peak heat release from 692 kW/m2 to 233 kW/m2 on GRE with significant intumescence of the coating. The coating was further tested for the adhesion to the surface of the substrate using a tape pull test, and for its durability in water using a water soak test. Whilst the coating showed good flame retardance and adhesion to the surface of the polymer substrate, the performance during water soak testing was poor due to the hydrophilicity of the poly(vinyl phosphonic acid). Further modifications were then made to the coating in order to improve its performance during the water soak test, the modifications made to the coating included the addition of additives and co monomers as well as the application of a secondary protective coating over the flame retardant (PVPA) to prevent attack from water. All synthesised coatings were tested using cone calorimetry, tape pull and water soak testing, as well as thermogravimetric analysis (TGA) and FTIR in order to provide further characterisation. The monomers, additives and top coatings tested were; dimethylvinylphosphonate, dibromostyrene, acrylonitrile, polydimethylsiloxane, magnesium oxide, zinc chloride, calcium silicate, chitosan, hexamethyldisiloxane, tetraethylorthosilicate, calixarene, vinyl acetate emulsion, commercial waterproofing spray, cellulose nitrate and cellulose acetate.While some improvements were made to the performance of the PVPA flame retardant coating through the use of additives, co monomers and top coatings there was no significant overall improvement which would render the PVPA coating suitable as a flame retardant coating with reasonable durability, with many of the improvements in water resistance resulting in a significant decrease in flame retardance. However this still leaves the path open to further research, with further possible modifications and combinations of already tested methods
Introducing the new Turnitin Feedback Studio
No full textFrom 1st August 2017 the Document Viewer (GradeMark) component of Turnitin will be replaced with a new tool called Feedback Studio.While the process of accessing Turnitin, setting up assignments and submitting work will not change, there are major improvements in the way you can provide feedback and view originality reports
Aqueous solutions of random poly(methyl methacrylate-co-acrylic acid): effect of the acrylic acid content
No full textAqueous solutions from two types of PMMA–AA polymers (PMMA–25AA and PMMA–50AA) are investigated. The aim is to outline the effect of AA content on the bulk solution and air/solution interface properties. The experiments include dynamic light scattering, surface tension and interfacial rheology measurements. The drainage kinetics and stability of microscopic foam films are also investigated. It is established that at similar conditions (pH = 10, temperature 20 °C) the polymer molecules have almost the same mean molecular weight and size distribution of the bulk globules. Dynamic and equilibrium surface tension measurements reveal systematically higher values for PMMA–50AA as compared to PMMA–25AA. These outcomes are related to higher bulk electrophoretic mobility in the PMMA–50AA case and the overall more stretched configuration of the polymer at the air/solution interface. Surface dilational rheology characteristics are particularly sensitive to the polymer structural peculiarities: while no significant changes are registered in the case of PMMA–25AA, the solutions of PMMA–50AA exhibit a pronounced maximum in surface dilational elasticity for the concentration ∼1 × 10−4 mol L−1. This observation is a clear sign of specific bulk and/or interfacial (structure) transition which has to be investigated in further studies. Microscopic foam films provide additional evidence for the effect of fine-tuning the AA content of the copolymer. All microscopic films are stable which is due predominantly to the overwhelming electrostatic repulsion effects. The obtained results add new knowledge to the structure–property relationships of the PMMA–AA based aqueous formulations. They give valuable hints for further fine-tuning opportunities of these systems, that have high innovative potential for various applications
Understanding TQM implementation barriers involving construction companies in a difficult environment
No full textAt society level, the findings of this study indicate societal problems such as corruption and business environment which require wide level approaches to deal with these barriers. In addition, if TQM applied in road construction projects, the quality of the roads will be improved, this in turn will have direct impact on quality of life in the society, better roads means easier access to hospitals, schools and public places, better transport and movements of goods and services, etc. It can also save money for the country in long run and economic benefits to the society
Reimagining undergraduate health and social care education: a workforce fit for purpose in a changing landscape of care. A position paper
No full textNHS England’s Five Year Forward View outlines new care models and the need for a workforce that has the skills, values, and competencies to deliver this vision. This is a position paper detailing the context, method, and intentions of a Health Education England funded project led by Manchester Metropolitan University in the North West of England, which the authors see as making a key contribution to addressing issues of illness, crisis, and loss in the changing landscape of health and social care provision in England. Using an action research methodology and drawing together key stakeholders from the sector, the project aims to explore the potential for creating a professional health and social care graduate workforce which meets the needs of an integrated service delivery landscape by identifying key issues to be addressed when redeveloping the undergraduate curriculum
Performance improvement in complex organizations: the case of smallholder agricultural cooperatives in Malawi
No full textSmallholder agricultural cooperatives have potential to play a vital role in the Malawi economy where smallholder farmers comprise the majority of the agricultural producers. Smallholder farmers individually have little power in the market place but when organized into cooperatives they enjoy protection from exploitation. The formation of cooperatives among smallholder farmers has therefore been accelerated and they now account for more than 55% of all cooperatives in Malawi. However, studies have concluded that the performance of the smallholder agricultural cooperatives is poor, and this research study has also confirmed this conclusion. This thesis therefore attempts to address the research problem: “How to improve the performance of smallholder agricultural cooperatives in Malawi”? The primary aim of this study was to develop a framework for improving the performance of smallholder agricultural cooperatives in Malawi.The research study utilized an interpretive paradigm to explore and describe the various factors that contribute to the poor performance of smallholder agricultural cooperatives. The multiple case study approach was used to gather data for this research study. A total of 8 case studies were conducted among smallholder agricultural cooperatives, and the empirical data that was collected was further analyzed using grounded theory analysis. The findings took the form of factors which contribute to the poor performance of smallholder agricultural cooperatives. A total of 18 factors were identified as contributing to poor performance of smallholder agricultural cooperatives. Thereafter, a performance improvement framework called the Maganga PISHAC Framework was developed by combining the identified factors into four core categories, namely; objectives, knowledge, skills and attitudes. The Maganga PISHAC Framework was constructed by integrating the findings of this study with the current literature in both the cooperative and performance improvement arenas. The Maganga PISHAC Framework can also be customized for use in other countries
Who sets the agenda on student engagement?
No full textThe rise in UK university fees has prompted significant investment in the student experience, with increased emphasis on an agenda that promotes student engagement and partnership. Government papers, both white and green, have set out a policymaking agenda and have led to a reorganisation of the UK higher education funding structures, with the dissolution of long-standing funding bodies into the Office for Students. This enshrines chapter B6 of the QAA UK quality code for higher education with regard to student engagement and would appear to be a positive move forward. However, the Office for Students has limited student representation and this raises the question: ‘Who sets this agenda and who are the stakeholders?’ This opinion piece seeks both to highlight the necessity for a joint agenda-setting approach and to engage the community in developing a joint agenda on student engagement and partnership
Three-Dimension Space Vector Modulation for Three-Level Four-Leg Inverters with DC-Link Capacitor Voltage Balancing and Switching Loss Minimization RENEWABLE ENERGY IMPACT
No full textDue to the trend of decentralized generation (DG) residing in low voltage distribution network, more inverters are connected to the grid in three-phase four-wire systems under asymmetrical condition. This paper presents an algorithm to balance DC-link capacitor voltages and minimize switching loss of three-level four-leg inverters which is suitable for asymmetrical condition. The algorithm is based on three-dimension space vector modulation (3D-SVM) in natural coordinates. The algorithm balances DC-link capacitor voltages by the selection of redundant standard vectors. Switching sequences are selected to minimize switching loss. Simulation results show that the method is able to balance DC-link capacitor voltages and reduce middle point voltage ripple