Novel biodegradable fibres for applications in tissue engineering and drug delivery

The preparation and characterisation of novel biodegradable polymer fibres for application in tissue engineering and drug delivery are reported. Poly(e-caprolactone) (PCL) fibres were produced by wet spinning from solutions in acetone under low shear (gravity flow) conditions. The tensile strength and stiffness of as-spun fibres were highly dependent on the concentration of the spinning solution. Use of a 6% w/v solution resulted in fibres having strength and stiffness of 1.8 MPa and 0.01 GPa respectively, whereas these values increased to 9.9 MPa and 0.1 GPa when fibres were produced from 20% w/v solutions. Cold drawing to an extension of 500% resulted in further increases in fibre strength (up to 50 MPa) and stiffness (0.3 GPa). Hot drawing to 500% further increased the fibre strength (up to 81 MPa) and stiffness (0.5 GPa). The surface morphology of as-spun fibres was modified, to yield a directional grooved pattern by drying in contact with a mandrel having a machined topography characterised by a peak-peak separation of 91 mm and a peak height of 30 mm. Differential scanning calorimetery (DSC) analysis of as-spun fibres revealed the characteristic melting point of PCL at around 58°C and a % crystallinity of approximately 60%. The biocompatibility of as-spun fibres was assessed using cell culture. The number of attached 3T3 Swiss mouse fibroblasts, C2C12 mouse myoblasts and human umbilical vein endothelial cells (HUVECs) on as-spun, 500% cold drawn, and gelatin coated PCL fibres were observed. The results showed that the fibres promoted cell proliferation for 9 days in cell culture and was slightly lower than on tissue culture plastic. The morphology of all cell lines was assessed on the various PCL fibres using scanning electron microscopy. The cell function of HUVECs growing on the as-spun PCL fibres was evaluated. The ability HUVECs to induce an immune response when stimulated with lipopolysaccaride (LPS) and thereby to increase the amount of cell surface receptors was assessed by flow cytometry and reverse transcription-polymerase chain reaction (RT-PCR). The results showed that PCL fibres did not inhibit this function compared to TCP. As-spun PCL fibres were loaded with 1 % ovine albumin (OVA) powder, 1% OVA nanoparticles and 5% OVA nanoparticles by weight and the protein release was assessed in vitro. PCL fibres loaded with 1 % OVA powder released 70%, 1% OVA nanoparticle released 60% and the 5% OVA nanoparticle released 25% of their protein content over 28 days. These release figures did not alter when the fibres were subjected to lipase enzymatic degradation. The OVA released was examined for structural integrity by SDS-PAGE. This showed that the protein molecular weight was not altered after incorporation into the fibres. The bioactivity of progesterone was assessed following incorporation into PCL fibres. Results showed that the progesterone released had a pronounced effect on MCF-7 breast epithelial cells, inhibiting their proliferation. The PCL fibres display high fibre compliance, a potential for controlling the fibre surface architecture to promote contact guidance effects, favorable proliferation rate of fibroblasts, myoblasts and HUVECs and the ability to release pharmaceuticals. These properties recommended their use for 3-D scaffold production in soft tissue engineering and the fibres could also be exploited for controlled presentation and release of biopharmaceuticals such as growth factors.

Methods of energy recovery in the iron and steel industry: evalution of new possibilities and design studies for slab cooling

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A cybernetic methodology to study and design human activities

This thesis offers a methodology to study and design effective communication mechanisms in human activities. The methodology is focused in the management of complexity. It is argued that complexity is not something objective that can be worked out analytically, but something subjective that depends on the viewpoint. Also it is argued that while certain social contexts may inhibit, others may enhance the viewpoint's capabilities to deal with complexity. Certain organisation structures are more likely than others to allow individuals to release their potentials. Thus, the relevance of studying and designing effective organisations. The first part of the thesis offers a `cybernetic methodology' for problem solving in human activities, the second offers a `method' to study and design organisations. The cybernetics methodology discussed in this work is rooted in second order cybernetics, or the cybernetics of the observing systems (Von Foester 1979, Maturana and Varela 1980). Its main tenet is that the known properties of the real world reside in the individual and not in the world itself. This view, which puts emphasis in a, by nature, one sided and unilateral appreciation of reality, triggers the need for dialogue and conversations to construct it. The `method' to study and design organisations, it based on Beer's Viable System Model (Beer 1979, 1981, 1985). This model permits us to assess how successful is an organisation in coping with its environmental complexity, and, moreover, permits us to establish how to make more effective the responses to this complexity. These features of the model are of great significance in a world where complexity is perceived to be growing at an unthinkable pace. But, `seeing' these features of the model assumes an effective appreciation of organisational complexity; hence the need for the methodological discussions offered by the first part of the thesis.

Structural behaviour and design of load-bearing falsework

Tne object of this research was to investigate the behaviour of birdcage scaffolding as used in falsework structures, assess the suitability of existing design methods and make recommendations for a set of design rules. Since excessive deflection is as undesirable in a structure as total collapse, the project was divided into two sections. These were to determine the ultimate vertical and horizontal load-carrying capacity and also the deflection characteristics of any falsework. So theoretical analyses were developed to ascertain the ability of both the individual standards to resist vertical load, and of the bracing to resist horizontal load.Furthermore a model was evolved which would predict the horizontal deflection of a scaffold under load using strain energy methods. These models were checked by three series of experiments. The first was on individual standards under vertical load only. The second series was carried out on full scale falsework structures loading vertically and horizontally to failure. Finally experiments were conducted on scaffold couplers to provide additional verification of the method of predicting deflections. This thesis gives the history of the project and an introduction into the field of scaffolding. It details both the experiments conducted and the theories developed and the correlation between theory and experiment. Finally it makes recommendations for a design method to be employed by scaffolding designers.

Evaluating design implementation strategies using enterprise simulation

Concurrent engineering and design for manufacture and assembly strategies have become pervasive in use in a wide array of industrial settings. These strategies have generally focused on product and process design issues based on capability concerns. The strategies have been historically justified using cost savings calculations focusing on easily quantifiable costs such as raw material savings or manufacturing or assembly operations no longer required. It is argued herein that neither the focus of the strategies nor the means of justification are adequate. Product and process design strategies should include both capability and capacity concerns and justification procedures should include the financial effects that the product and process changes would have on the entire company. The authors of this paper take this more holistic view of the problem and examine an innovative new design strategy using a comprehensive enterprise simulation tool. The results indicate that both the design strategy and the simulator show promise for further industrial use. © 2001 Elsevier Science B.V. All rights reserved.

The evolution and design of safety management systems

Research in safety management has been inhibited by lack of consensus as to the definitions of the terms with which it is concerned and, in general, the lack of an agreed theoretical framework within which to collate and contrast empirical findings. This thesis sets out definitions of key terms (hazard, risk, accident, incident and safety) and provides a theoretical framework. This framework has been informed by many sources but especially the Management Oversight and Risk Tree (MORT), cybernetics and the Viable System Model (VSM). Fieldwork designs are proposed for the empirical development of an analytical framework and its use to assist study of the development of safety management in organisations.

Realising competitive advantage:bicycle manufacture - manufacturing engineering and management

Students at Cranfield Manufacturing Systems Centre helped Brompton Bikes formulate a strategy to meet rapid sales growth. The students took up Operations Excellence MSc, a two-year part-time programme based on the Cranfield MSc in Engineering and Management of Manufacturing Systems, include the Realising Competitive Manufacture module, which is set out to consolidate and embed the knowledge and skills developed throughout the two-year programme. Guided by StratNav process, the students analysed the product families of Brompton, established the basis on which they compete in the market place, and then benchmarked against key competitors. The top five developments identified to be needed by Brompton are: the formation of group technology cells, creation of a robotic brazing facility, and training and recruitment initiatives for production staff.

Proposal and design of airy-based rocket pulses for invariant propagation in lossy dispersive media

A novel kind of Airy-based pulse with an invariant propagation in lossy dispersive media is proposed. The basic principle is based on an optical energy trade-off between different parts of the pulse caused by the chromatic dispersion, which is used to compensate the attenuation losses of the propagation medium. Although the ideal concept of the proposed pulses implies infinite pulse energy, the numerical simulations show that practical finite energy pulses can be designed to obtain a partially invariant propagation over a finite distance of propagation.

Ultrafast all-optical integrator based on a fiber Bragg grating:proposal and design

We demonstrate a simple technique for the implementation of an all-optical integrator based on a uniform-period fiber Bragg grating (FBG) in reflection that is designed to present a decreasing exponential impulse response. The proposed FBG integrator is readily feasible and can perform close to ideal integration of few-picosecond and subpicosecond pulses.

Evaluating and developing project-based learning:an empirical approach to evaluating CDIO

As a global profession, engineering is integral to the maintenance and further development of society. Indeed, contemporary social problems requiring engineering solutions are not only a consequence of natural and ‘manmade’ disasters (such as the Japanese earthquake or the oil leakage in the Gulf of Mexico) but also encapsulate 21st Century dilemmas around sustainability, poverty and pollution [2,6,7]. Given the complexity of such problems and the constant need for innovation, the demand for engineering education to provide a ready supply of suitably qualified engineering graduates, able to make innovative decisions has never been higher [3,5]. Bearing this in mind, and taking account problems of attrition in engineering education [1,6,4] innovation in the way in which the curriculum is developed and delivered is crucial. CDIO [Conceive, Design, Implement, Operate] provides a potentially ground-breaking solution to such dilemmas. Aimed at equipping students with practical engineering skills supported by the necessary theoretical background, CDIO could potentially change the way engineering is perceived and experienced within higher education. Aston University introduced CDIO into its Mechanical Engineering and Design programmes in October 2011. From its induction, engineering education researchers have ‘shadowed’ the staff responsible for developing and teaching the programme. Utilising an Action Research Design, and adopting a mixed methodological research design, the researchers have worked closely with the teaching team to critically reflect on the processes involved in introducing CDIO into the curriculum. Concurrently, research has been conducted to capture students’ perspectives of CDIO. In evaluating the introduction of CDIO at Aston, the researchers have developed a distinctive research strategy with which to evaluate CDIO. It is the emergent findings from this research that form the basis of this paper. Although early-on in its development CDIO is making a significant difference to engineering education at the University. The paper draws attention to pedagogical, practical and professional issues – discussing each one in turn and in doing so critically analysing the value of CDIO from academic, student and industrial perspectives. The paper concludes by noting that whilst CDIO represents a forwardthinking approach to engineering education, the need for constant innovation in learning and teaching should not be forgotten. Indeed, engineering education needs to put itself at the forefront of pedagogic practice. Providing all-rounded engineers, ready to take on the challenges of the 21st Century!

Race car vehicle dynamics and design applied to formula student

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