Fluid Mechanics and Thermodynamics of Turbomachinery

For this new edition, author S. Larry Dixon is joined by Cesare Hall from the University of Cambridge, whose diverse background of teaching, research and work ...

Electrically conductive, melt-processed ternary blends of polyaniline/dodecylbenzene sulfonic acid, ethylene/vinyl acetate, and low-density polyethylene

Although polyaniline (PANI) has high conductivity and relatively good environmental and thermal stability and is easily synthesized, the intractability of this intrinsically conducting polymer with a melting procedure prevents extensive applications. This work was designed to process PANI with a melting blend method with current thermoplastic polymers. PANI in an emeraldine base form was plasticized and doped with dodecylbenzene sulfonic acid (DBSA) to prepare a conductive complex (PANI-DBSA). PANI-DBSA, low-density polyethylene (LDPE), and an ethylene/vinyl acetate copolymer (EVA) were blended in a twin-rotor mixer. The blending procedure was monitored, including the changes in the temperature, torque moment, and work. As expected, the conductivity of ternary PANI-DBSA/LDPE/EVA was higher by one order of magnitude than that of binary PANI-DBSA/LDPE, and this was attributed to the PANI-DBSA phase being preferentially located in the EVA phase. An investigation of the morphology of the polymer blends with high-resolution optical microscopy indicated that PANI-DBSA formed a conducting network at a high concentration of PANI-DBSA. The thermal and crystalline properties of the polymer blends were measured with differential scanning calorimetry. The mechanical properties were also measured.

Miscibility and crystallization behavior of PBT/epoxy blends

The miscibility and the isothermal crystallization kinetics for PBT/Epoxy blends have been studied by using differential scanning calorimetry, and several kinetic analyses have been used to describe the crystallization process. The Avrami exponents n were obtained for PBT/Epoxy blends. An addition of small amount of epoxy resin (3%) leads to an increase in the number of effective nuclei, thus resulting in an increase in crystallization rate and a stronger trend of instantaneous three-dimensional growth. For isothermal crystallization, crystallization parameter analysis showed that epoxy particles could act as effective nucleating agents, accelerating the crystallization of PBT component in the PBT/Epoxy blends. The Lauritzen-Hoffman equation for DSC isothermal crystallization data revealed that PBT/Epoxy 97/3 had lower nucleation constant K, than 100/0, 93/7, and 90/10 PBT/Epoxy blends. Analysis of the crystallization data of PBT/Epoxy blends showed that crystallization occurs in regime II. The fold surface free energy, sigma(e) = 101.7-58.0 x 10(-3) J/m(2), and work of chain folding, q = 5.79-3.30 kcal/mol, were determined. The equilibrium melting point depressions of PBT/Epoxy blends were observed and the Flory-Huggins interaction parameters were obtained.

A QSAR of the toxicity of amino-benzenes and their structures

The quantum chemical parameters and the topological indices have been calculated for the prediction of the toxicity of amino-benzenes in the environment, and work has been done on the multiple regression and neural networks. The combination of CoMFA with formation heat yields greatly improved results. A good model has been obtained which provides a basis for the studies of the toxic action mechanism.

The effects of physical ageing on crazing of polyphenylquinoxaline films

The effects of physical ageing on the crazing of polyphenylquinoxaline (PPQ-E) films were studied. The DSC endothermic peak at the glass transition region of the samples was interpreted in terms of the cohesional entanglement theory. The free volume cavity size and free volume intensity of the samples were characterized by positron annihilation life spectroscopy. The difference in free volume cavity size and free volume intensity between two samples reflect the strength and density of cohensional entanglement point. The critical strain for craze initiation and craze stability depended on physical ageing of the samples. The relationships between physical ageing and crazing were interpreted initially.

An ethnographic interpretation of the work environment within a creative culture in the advertising sector.

Purpose and rationale The purpose of the exploratory research is to provide a deeper understanding of how the work environment enhances or constrains organisational creativity (creativity and innovation) within the context of the advertising sector. The argument for the proposed research is that the contemporary literature is dominated by quantitative research instruments to measure the climate and work environment across many different sectors. The most influential theory within the extant literature is the componential theory of organisational creativity and innovation and is used as an analytical guide (Amabile, 1997; Figure 8) to conduct an ethnographic study within a creative advertising agency based in Scotland. The theory suggests that creative people (skills, expertise and task motivation) are influenced by the work environment in which they operate. This includes challenging work (+), work group supports (+), supervisory encouragement (+), freedom (+), sufficient resources (+), workload pressures (+ or -), organisational encouragement (+) and organisational impediments (-) which is argued enhances (+) or constrains (-) both creativity and innovation. An interpretive research design is conducted to confirm, challenge or extend the componential theory of organisational creativity and innovation (Amabile, 1997; Figure 8) and contribute to knowledge as well as practice. Design/methodology/approach The scholarly activity conducted within the context of the creative industries and advertising sector is in its infancy and research from the alternative paradigm using qualitative methods is limited which may provide new guidelines for this industry sector. As such, an ethnographic case study research design is a suitable methodology to provide a deeper understanding of the subject area and is consistent with a constructivist ontology and an interpretive epistemology. This ontological position is conducive to the researcher’s axiology and values in that meaning is not discovered as an objective truth but socially constructed from multiple realties from social actors. As such, ethnography is the study of people in naturally occurring settings and the creative advertising agency involved in the research is an appropriate purposive sample within an industry that is renowned for its creativity and innovation. Qualitative methods such as participant observation (field notes, meetings, rituals, social events and tracking a client brief), material artefacts (documents, websites, annual reports, emails, scrapbooks and photographic evidence) and focused interviews (informal and formal conversations, six taped and transcribed interviews and use of Survey Monkey) are used to provide a written account of the agency’s work environment. The analytical process of interpreting the ethnographic text is supported by thematic analysis (selective, axial and open coding) through the use of manual analysis and NVivo9 software Findings The findings highlight a complex interaction between the people within the agency and the enhancers and constraints of the work environment in which they operate. This involves the creative work environment (Amabile, 1997; Figure 8) as well as the physical work environment (Cain, 2012; Dul and Ceylan, 2011; Dul et al. 2011) and that of social control and power (Foucault, 1977; Gahan et al. 2007; Knights and Willmott, 2007). As such, the overarching themes to emerge from the data on how the work environment enhances or constrains organisational creativity include creative people (skills, expertise and task motivation), creative process (creative work environment and physical work environment) and creative power (working hours, value of creativity, self-fulfilment and surveillance). Therefore, the findings confirm that creative people interact and are influenced by aspects of the creative work environment outlined by Amabile (1997; Figure 8). However, the results also challenge and extend the theory to include that of the physical work environment and creative power. Originality/value/implications Methodologically, there is no other interpretive research that uses an ethnographic case study approach within the context of the advertising sector to explore and provide a deeper understanding of the subject area. As such, the contribution to knowledge in the form of a new interpretive framework (Figure 16) challenges and extends the existing body of knowledge (Amabile, 1997; Figure 8). Moreover, the contribution to practice includes a flexible set of industry guidelines (Appendix 13) that may be transferrable to other organisational settings.

Exploring the relationship between impulsivity and decision-making on mobile devices.

Mobile devices offer a common platform for both leisure and work-related tasks but this has resulted in a blurred boundary between home and work. In this paper we explore the security implications of this blurred boundary, both for the worker and the employer. Mobile workers may not always make optimum security-related choices when ‘on the go’ and more impulsive individuals may be particularly affected as they are considered more vulnerable to distraction. In this study we used a task scenario, in which 104 users were asked to choose a wireless network when responding to work demands while out of the office. Eye-tracking data was obtained from a subsample of 40 of these participants in order to explore the effects of impulsivity on attention. Our results suggest that impulsive people are more frequent users of public devices and networks in their day-to-day interactions and are more likely to access their social networks on a regular basis. However they are also likely to make risky decisions when working on-the-go, processing fewer features before making those decisions. These results suggest that those with high impulsivity may make more use of the mobile Internet options for both work and private purposes but they also show attentional behavior patterns that suggest they make less considered security-sensitive decisions. The findings are discussed in terms of designs that might support enhanced deliberation, both in the moment and also in relation to longer term behaviors that would contribute to a better work-life balance.

Shear effects on the properties and separation characteristics of whey protein precipitates

Selective isoelectric whey protein precipitation and aggregation is carried out at laboratory scale in a standard configuration batch agitation vessel. Geometric scale-up of this operation is implemented on the basis of constant impeller power input per unit volume and subsequent clarification is achieved by high speed disc-stack centrifugation. Particle size and fractal geometry are important in achieving efficient separation while aggregates need to be strong enough to resist the more extreme levels of shear that are encountered during processing, for example through pumps, valves and at the centrifuge inlet zone. This study investigates how impeller agitation intensity and ageing time affect aggregate size, strength, fractal dimension and hindered settling rate at laboratory scale in order to determine conditions conducive for improved separation. Particle strength is measured by observing the effects of subjecting aggregates to moderate and high levels of process shear in a capillary rig and through a partially open ball-valve respectively. The protein precipitate yield is also investigated with respect to ageing time and impeller agitation intensity. A pilot scale study is undertaken to investigate scale-up and how agitation vessel shear affects centrifugal separation efficiency. Laboratory scale studies show that precipitates subject to higher impeller shear-rates during the addition of the precipitation agent are smaller but more compact than those subject to lower impeller agitation and are better able to resist turbulent breakage. They are thus more likely to provide a better feed for more efficient centrifugal separation. Protein precipitation yield improves significantly with ageing, and 50 minutes of ageing is required to obtain a 70 - 80% yield of α-lactalbumin. Geometric scale-up of the agitation vessel at constant power per unit volume results in aggregates of broadly similar size exhibiting similar trends but with some differences due to the absence of dynamic similarity due to longer circulation time and higher tip speed in the larger vessel. Disc stack centrifuge clarification efficiency curves show aggregates formed at higher shear-rates separate more efficiently, in accordance with laboratory scale projections. Exposure of aggregates to highly turbulent conditions, even for short exposure times, can lead to a large reduction in particle size. Thus, improving separation efficiencies can be achieved by the identification of high shear zones in a centrifugal process and the subsequent elimination or amelioration of such.

Challengers to provisional republicanism: the official republican movement, people’s democracy and the Irish republican socialist party, 1968–98

The Provisional IRA and its political wing Sinn Féin have attracted by far the greatest scholarly interest of all the players in the Northern Irish conflict. This emphasis is perfectly legitimate, given the centrality of the Provos to so many turning-points in the conflict, from the collapse of Stormont in the early 1970s to the hunger strikes of the following decade and the ceasefires which were followed by the Belfast Agreement. My project, however, looks at political groups that at one time or another challenged the Provos for leadership of the militant, anti-state constituency in Northern Ireland (chiefly based in the Catholic working class). Although never as large or influential as the Provisional republicans, groups such as the Official IRA and the Irish Republican Socialist Party sometimes had a discernible impact on the course of events which is overlooked by most studies, and often pioneered ideas and tactics that were later adopted by the Provos themselves. The idea that republicans should embrace political action and work in broad campaigning alliances was promoted by the IRSP and socialist groups such as People’s Democracy before it was taken up by Gerry Adams and his allies, while the Official IRA supported the principle of a settlement based on democratization of the Northern Irish state, which was later accepted by Sinn Féin in the form of the Belfast Agreement. The goal of my research is to provide a novel perspective on the conflict in Northern Ireland, while engaging with theoretical debates about its character.

A microscopic study of structural and electronic properties of functionalized silicon surfaces based on first-principles

Surface modification of silicon with organic monolayers tethered to the surface by different linkers is an important process in realizing future (opto-)electronic devices. Understanding the role played by the nature of the linking group and the chain length on the adsorption structures and electronic properties of these assemblies is vital to advance this technology. This Thesis is a study of such properties and contributes in particular to a microscopic understanding of induced changes in the work function of experimentally studied functionalized silicon surfaces. Using first-principles density functional theory (DFT), at the first step, we provide predictions for chemical trends in the work function of hydrogenated silicon (111) surfaces modified with various terminations. For nonpolar terminating atomic species such as F, Cl, Br, and I, the change in the work function is directly proportional to the amount of charge transferred from the surface, thus relating to the difference in electronegativity of the adsorbate and silicon atoms. The change is a monotonic function of coverage in this case, and the work function increases with increasing electronegativity. Polar species such as −TeH, −SeH, −SH, −OH, −NH2, −CH3, and −BH2 do not follow this trend due to the interaction of their dipole with the induced electric field at the surface. In this case, the magnitude and sign of the surface dipole moment need to be considered in addition to the bond dipole to generally describe the change in work function. Compared to hydrogenated surfaces, there is slight increase in the work function of H:Si(111)-XH, where X = Te, Se, and S, whereas reduction is observed for surfaces covered with −OH, −CH3, and −NH2. Next, we study the hydrogen passivated Si(111) surface modified with alkyl chains of the general formula H:Si–(CH2)n–CH2 and H:Si–X–(CH2)n–CH3, where X = NH, O, S and n = (0, 1, 3, 5, 7, 9, 11), at half coverage. For (X)–Hexyl and (X)–Dodecyl functionalization, we also examined various coverages up to full monolayer grafting in order to validate the result of half covered surface and the linker effect on the coverage. We find that it is necessary to take into account the van der Waals interaction between the alkyl chains. The strongest binding is for the oxygen linker, followed by S, N, and C, irrespective of chain length. The result revealed that the sequence of the stability is independent of coverage; however, linkers other than carbon can shift the optimum coverage considerably and allow further packing density. For all linkers apart from sulfur, structural properties, in particular, surface-linker-chain angles, saturate to a single value once n > 3. For sulfur, we identify three regimes, namely, n = 0–3, n = 5–7, and n = 9–11, each with its own characteristic adsorption structures. Where possible, our computational results are shown to be consistent with the available experimental data and show how the fundamental structural properties of modified Si surfaces can be controlled by the choice of linking group and chain length. Later we continue by examining the work function tuning of H:Si(111) over a range of 1.73 eV through adsorption of alkyl monolayers with general formula -[Xhead-group]-(CnH2n)-[Xtail-group], X = O(H), S(H), NH(2). The work function is practically converged at 4 carbons (8 for oxygen), for head-group functionalization. For tail-group functionalization and with both head- and tail-groups, there is an odd-even effect in the behavior of the work function, with peak-to-peak amplitudes of up to 1.7 eV in the oscillations. This behavior is explained through the orientation of the terminal-group's dipole. The shift in the work function is largest for NH2-linked and smallest for SH-linked chains and is rationalized in terms of interface dipoles. Our study reveals that the choice of the head- and/or tail-groups effectively changes the impact of the alkyl chain length on the work function tuning using self-assembled monolayers and this is an important advance in utilizing hybrid functionalized Si surfaces. Bringing together the understanding gained from studying single type functionalization of H:Si(111) with different alkyl chains and bearing in mind how to utilize head-group, tail-group or both as well as monolayer coverage, in the final part of this Thesis we study functionalized H:Si(111) with binary SAMs. Aiming at enhancing work function adjustment together with SAM stability and coverage we choose a range of terminations and linker-chains denoted as –X–(Alkyl) with X = CH3, O(H), S(H), NH(2) and investigate the stability and work function of various binary components grafted onto H:Si(111) surface. Using binary functionalization with -[NH(2)/O(H)/S(H)]-[Hexyl/Dodecyl] we show that work function can be tuned within the interval of 3.65-4.94 eV and furthermore, enhance the SAM’s stability. Although direct Si-C grafted SAMs are less favourable compared to their counterparts with O, N or S linkage, regardless of the ratio, binary functionalized alkyl monolayers with X-alkyl (X = NH, O) is always more stable than single type alkyl functionalization with the same coverage. Our results indicate that it is possible to go beyond the optimum coverage of pure alkyl functionalized SAMs (50%) by adding a linker with the correct choice of the linker. This is very important since dense packed monolayers have fewer defects and deliver higher efficiency. Our results indicate that binary anchoring can modify the charge injection and therefore bond stability while preserving the interface electronic structure.

On "fitting in": the effects of social context and gender on big 5 trait expression.

[This is a summary of an Oral Presentation] The study explored the expression of Big 5 personality traits in three different social contexts (with parents friends and work colleagues) to test the prediction that personality is socially variable due to the motivation to ‘fit in’. The questionnaire-based method produced results that support this hypothesis; all Big 5 traits were significantly variable across contexts with Conscientiousness the least variable and Extraversion possessiveness. The results indicated that females reported being more distressed than males and older respondents reported being less distressed then younger respondents. The findings from this study contribute to the literature on online infidelity in terms of understanding differences in the way it is perceived.

Research supervision and psychotherapeutic theory: bridging the research-practice-gap

Research supervision in the field of counselling and psychotherapy is a fruitful area for investigation in view of the fact that the research supervisory relationship is powerful and highly charged, whether consciously acknowledged or not. Researchers trained as counsellors and psychotherapists possess the skills to facilitate the emergence of, and work creatively with, impasses and crises, both in the research itself and the supervisory relationship, as a result of their training and experience in dealing with crisis and catharsis in clinical work. This paper will demonstrate these points using a case vignette from my work as a supervisor of research dissertations undertaken by students on a Masters in Therapeutic Counselling course. Drawing on narrative analysis, clinical supervision theory and discursive analysis it will look at the strengths and weaknesses of a 'psychotherapeutic' approach to research supervision.

Continuing Professional Development: rhetoric and practice in the NHS

This article explores the experience of Continuing Professional Development (CPD) by supervisory-level clinical staff in the National Health Service. Four main themes are highlighted in the literature, namely the nature and experience of CPD, its relationship with human resource management practices and in particular in career development and planning. These themes are examined utilising sources of (triangulated) empirical data based on a 2500 sample survey conducted across five NHS Trusts. A key finding was that responsibility for learning and development was perceived as belonging to the individual rather than the organisation. Other findings concern a lack of resource-based commitment by the organisation to CPD for clinical staff undertaking supervisory-level roles and evidence of 'credentialism' with its emphasis on seeking certificated qualifications. The findings raise concerns about the potential for clinical staff to become disillusioned and to perceive a potential breach in their psychological contract because of problems in reconciling their own interests with those of their professional body, and that of their employer in relation to CPD.

Bridging the gap with teamwork: collaborative leadership for communities of practice in the learning and skills sector

Collaborative approaches in leadership and management are increasingly acknowledged to play a key role in successful institutions in the learning and skills sector (LSS) (Ofsted, 2004). Such approaches may be important in bridging the potential 'distance' (psychological, cultural, interactional and geographical) (Collinson, 2005) that may exist between 'leaders' and 'followers', fostering more democratic communal solidarity. This paper reports on a 2006-07 research project funded by the Centre for Excellence in Leadership (CEL) that aimed to collect and analyse data on 'collaborative leadership' (CL) in the learning and skills sector. The project investigated collaborative leadership and its potential for benefiting staff through trust and knowledge-sharing in communities of practice (CoPs). The project forms part of longer-term educational research investigating leadership in a collaborative inquiry process (Jameson et al., 2006). The research examined the potential for CL to benefit institutions, analysing respondents' understanding of and resistance to collaborative practices. Quantitative and qualitative data from senior managers and lecturers was analysed using electronic data in SPSS and Tropes Zoom. The project aimed to recommend systems and practices for more inclusive, diverse leadership (Lumby et al., 2005). Collaborative leadership has increasingly gained international prominence as emphasis shifted towards team leadership beyond zero-sum 'leadership'/ 'followership' polarities into more mature conceptions of shared leadership spaces, within which synergistic leadership spaces can be mediated. The relevance of collaboration within the LSS has been highlighted following a spate of recent government-driven policy developments in FE. The promotion of CL addresses concerns about the apparent 'remoteness' of some senior managers, and the 'neo-management' control of professionals which can increase 'distance' between leaders and 'followers' and may de-professionalise staff in an already disempowered sector. Positive benefit from 'collaborative advantage' tends to be assumed in idealistic interpretations of CL, but potential 'collaborative inertia' may be problematic in a sector characterised by rapid top-down policy changes and continuous external audit and surveillance. Constant pressure for achievement against goals leaves little time for democratic group negotiations, despite the desires of leaders to create a more collaborative ethos. Yet prior models of intentional communities of practice potentially offer promise for CL practice to improve group performance despite multiple constraints. The CAMEL CoP model (JISC infoNet, 2006) was linked to the project, providing one practical way of implementing CL within situated professional networks.The project found that a good understanding of CL was demonstrated by most respondents, who thought it could enable staff to share power and work in partnership to build trust and conjoin skills, abilities and experience to achieve common goals for the good of the sector. However, although most respondents expressed agreement with the concept and ideals of CL, many thought this was currently an idealistically democratic, unachievable pipe dream in the LSS. Many respondents expressed concerns with the 'audit culture' and authoritarian management structures in FE. While there was a strong desire to see greater levels of implementation of CL, and 'collaborative advantage' from the 'knowledge sharing benefit potential' of team leadership, respondents also strongly advised against the pitfalls of 'collaborative inertia'. A 'distance' between senior leadership views and those of staff lower down the hierarchy regarding aspects of leadership performance in the sector was reported. Finally, the project found that more research is needed to investigate CL and develop innovative methods of practical implementation within autonomous communities of professional practice.