Design of a Semi-analytical Method to Describe Plasma-Wall Interactions

Electric probes are objects immersed in the plasma with sharp boundaries which collect of emit charged particles. Consequently, the nearby plasma evolves under abrupt imposed and/or naturally emerging conditions. There could be localized currents, different time scales for plasma species evolution, charge separation and absorbing-emitting walls. The traditional numerical schemes based on differences often transform these disparate boundary conditions into computational singularities. This is the case of models using advection-diffusion differential equations with source-sink terms (also called Fokker-Planck equations). These equations are used in both, fluid and kinetic descriptions, to obtain the distribution functions or the density for each plasma species close to the boundaries. We present a resolution method grounded on an integral advancing scheme by using approximate Green's functions, also called short-time propagators. All the integrals, as a path integration process, are numerically calculated, what states a robust grid-free computational integral method, which is unconditionally stable for any time step. Hence, the sharp boundary conditions, as the current emission from a wall, can be treated during the short-time regime providing solutions that works as if they were known for each time step analytically. The form of the propagator (typically a multivariate Gaussian) is not unique and it can be adjusted during the advancing scheme to preserve the conserved quantities of the problem. The effects of the electric or magnetic fields can be incorporated into the iterative algorithm. The method allows smooth transitions of the evolving solutions even when abrupt discontinuities are present. In this work it is proposed a procedure to incorporate, for the very first time, the boundary conditions in the numerical integral scheme. This numerical scheme is applied to model the plasma bulk interaction with a charge-emitting electrode, dealing with fluid diffusion equations combined with Poisson equation self-consistently. It has been checked the stability of this computational method under any number of iterations, even for advancing in time electrons and ions having different time scales. This work establishes the basis to deal in future work with problems related to plasma thrusters or emissive probes in electromagnetic fields.

Telomerase activity in the regenerative basal layer of the epidermis inhuman skin and in immortal and carcinoma-derived skin keratinocytes.

Cellular senescence is defined by the limited proliferative capacity of normal cultured cells. Immortal cells overcome this regulation and proliferate indefinitively. One step in the immortalization process may be reactivation of telomerase activity, a ribonucleoprotein complex, which, by de novo synthesized telomeric TTAGGG repeats, can prevent shortening of the telomeres. Here we show that immortal human skin keratinocytes, irrespective of whether they were immortalized by simian virus 40, human papillomavirus 16, or spontaneously, as well as cell lines established from human skin squamous cell carcinomas exhibit telomerase activity. Unexpectedly, four of nine samples of intact human skin also were telomerase positive. By dissecting the skin we could show that the dermis and cultured dermal fibroblasts were telomerase negative. The epidermis and cultured skin keratinocytes, however, reproducibly exhibited enzyme activity. By separating different cell layers of the epidermis this telomerase activity could be assigned to the proliferative basal cells. Thus, in addition to hematopoietic cells, the epidermis, another example of a permanently regenerating human tissue, provides a further exception of the hypothesis that all normal human somatic tissues are telomerase deficient. Instead, these data suggest that in addition to contributing to the permanent proliferation capacity of immortal and tumor-derived keratinocytes, telomerase activity may also play a similar role in the lifetime regenerative capacity of normal epidermis in vivo.

Correlação entre microestrutura e comportamento de corrosão em duas ligas do sistema Al-Fe-Si produzidas pelos processos industriais de lingotamento contínuo e semi-contínuo.

As chapas de ligas de alumínio trabalháveis são produzidas atualmente por dois processos, o método de vazamento contínuo conhecido TRC (Twin Roll Continous Casting) ou pelo método tradicional de vazamento de placas DC (Direct Chill). A fabricação de ligas de alumínio pelos dois processos confere características microestruturais diferentes quando comparadas entre si, o que se reflete em suas propriedades. Além disto, ocorrem variações microestruturais ao longo da espessura, especialmente nas chapas produzidas pelo processo TRC. Neste sentido, é importante estudar a evolução microestrutural que ocorre durante o seu processamento e sua influência com relação à resistência à corrosão. Dessa forma foi realizado neste trabalho um estudo comparativo do comportamento de corrosão, bem como das microestruturas do alumínio de alta pureza AA1199 (99,995% Al) e das ligas de alumínio AA1050 (Fe+Si0,5%) e AA4006 (Fe+Si1,8%) produzidas pelos processos industriais de lingotamento contínuo e semi-contínuo. Os resultados obtidos evidenciaram que as microestruturas das ligas AA4006 DC e AA4006 TRC são distintas, sendo observada maior fração volumétrica dos precipitados na liga fabricada pelo processo TRC comparativamente ao DC. Para caracterizar o comportamento de corrosão foram realizados ensaios de Espectroscopia de Impedância Eletroquímica e Polarização Potenciodinâmica, que mostraram a maior resistência à corrosão localizada para a liga fabricada pelo processo TRC em comparação ao processo DC. Além disso, foi verificada, em ordem decrescente, uma maior resistência à corrosão do alumínio AA1050, seguida pela superfície da liga AA4006 e por fim, pelo centro da chapa desta última. Os resultados obtidos por espectroscopia de impedância eletroquímica para as ligas AA4006 fabricadas pelo processo TRC apresentaram melhor desempenho que o processo DC, principalmente em intervalos de 2 a 12 horas de imersão na solução de sulfato de sódio contaminada com íons cloreto. Para tempos de imersão acima de 4 horas foi observado comportamento indutivo em baixas frequências para os dois tipos de processamento investigados, o que foi associado à adsorção de espécies químicas, principalmente íons sulfato e oxigênio, na interface metal/óxido. As curvas de polarização anódica mostraram maior resistência à corrosão localizada para a liga fabricada pelo processo viii TRC em comparação ao processo DC. Este comportamento foi associado às diferentes características microestruturais, observadas para liga AA4006 obtida pelos dois processos.

Semi-analytical solution for nonlinear vibration of laminated FGM plates with geometric imperfections

This paper investigates the nonlinear vibration of imperfect shear deformable laminated rectangular plates comprising a homogeneous substrate and two layers of functionally graded materials (FGMs). A theoretical formulation based on Reddy's higher-order shear deformation plate theory is presented in terms of deflection, mid-plane rotations, and the stress function. A semi-analytical method, which makes use of the one-dimensional differential quadrature method, the Galerkin technique, and an iteration process, is used to obtain the vibration frequencies for plates with various boundary conditions. Material properties are assumed to be temperature-dependent. Special attention is given to the effects of sine type imperfection, localized imperfection, and global imperfection on linear and nonlinear vibration behavior. Numerical results are presented in both dimensionless tabular and graphical forms for laminated plates with graded silicon nitride/stainless steel layers. It is shown that the vibration frequencies are very much dependent on the vibration amplitude and the imperfection mode and its magnitude. While most of the imperfect laminated plates show the well-known hard-spring vibration, those with free edges can display soft-spring vibration behavior at certain imperfection levels. The influences of material composition, temperature-dependence of material properties and side-to-thickness ratio are also discussed. (C) 2004 Elsevier Ltd. All rights reserved.

NMR imaging of the diffusion of water at 310 K into semi-IPNs of PEM and Poly(HEMA-co-THFMA)

Magnetic resonance imaging has been used to monitor the diffusion of water at 310 K into a series of semi-IPNs of poly(ethyl methacrylate), PEM, and copolymers of 2-hydroxyethyl methacrylate, HEMA, and tetrahydrofurfuryl methacrylate, THFMA. The diffusion was found to be well described by a Fickian kinetic model in the early stages of the water sorption process, and the diffusion coefficients were found to be slightly smaller than those for the copolymers of HEMA and THFMA, P(HEMA-co-THFMA), containing the same mole fraction of HEMA in the matrix. A second stage sorption process was identified in the later stage of water sorption by the PEM/PTHFMA semi-IPN and for the systems containing a P(HEMA-co-THFMA) component with a mole fraction HEMA of 0.6 or less. This was characterized by the presence of Water near the surface of the cylinders with a longer NMR T-2 relaxation time, which would be characteristic of mobile water, such as water present in large pores or surface fissures. The presence of the drug chlorhexidine in the polymer matrixes at a concentration of 5.625 wt % was found not to modify the properties significantly, but the diffusion coefficients for the water sorption were systematically smaller when the drug was present.

Referral to rehabilitation following traumatic brain injury: practitioners and the process of decision-making

The study aimed to examine the factors influencing referral to rehabilitation following traumatic brain injury (TBI) by using social problems theory as a conceptual model to focus on practitioners and the process of decision-making in two Australian hospitals. The research design involved semi-structured interviews with 18 practitioners and observations of 10 team meetings, and was part of a larger study on factors influencing referral to rehabilitation in the same settings. Analysis revealed that referral decisions were influenced primarily by practitioners' selection and their interpretation of clinical and non-clinical patient factors. Further, practitioners generally considered patient factors concurrently during an ongoing process of decision-making, with the combinations and interactions of these factors forming the basis for interpretations of problems and referral justifications. Key patient factors considered in referral decisions included functional and tracheostomy status, time since injury, age, family, place of residence and Indigenous status. However, rate and extent of progress, recovery potential, safety and burden of care, potential for independence and capacity to cope were five interpretative themes, which emerged as the justifications for referral decisions. The subsequent negotiation of referral based on patient factors was in turn shaped by the involvement of practitioners. While multi-disciplinary processes of decision-making were the norm, allied health professionals occupied a central role in referral to rehabilitation, and involvement of medical, nursing and allied health practitioners varied. Finally, the organizational pressures and resource constraints, combined with practitioners' assimilation of the broader efficiency agenda were central factors shaping referral. (C) 2004 Elsevier Ltd. All rights reserved.

A framework of issues in large process modeling projects

As process management projects have increased in size due to globalised and company-wide initiatives, a corresponding growth in the size of process modeling projects can be observed. Despite advances in languages, tools and methodologies, several aspects of these projects have been largely ignored by the academic community. This paper makes a first contribution to a potential research agenda in this field by defining the characteristics of large-scale process modeling projects and proposing a framework of related issues. These issues are derived from a semi -structured interview and six focus groups conducted in Australia, Germany and the USA with enterprise and modeling software vendors and customers. The focus groups confirm the existence of unresolved problems in business process modeling projects. The outcomes provide a research agenda which directs researchers into further studies in global process management, process model decomposition and the overall governance of process modeling projects. It is expected that this research agenda will provide guidance to researchers and practitioners by focusing on areas of high theoretical and practical relevance.

Semi-global techniques in image matching and change detection with applications to civil and environmental engineering.

This work of thesis wants to present a dissertation of the wide range of modern dense matching algorithms, which are spreading in different application and research fields, with a particular attention to the innovative “Semi-Global” matching techniques. The choice of develop a semi-global numerical code was justified by the need of getting insight on the variables and strategies that affect the algorithm performances with the primary objective of maximizing the method accuracy and efficiency, and the results level of completeness. The dissertation will consist in the metrological characterization of the proprietary implementation of the semi-global matching algorithm, evaluating the influence of several matching variables and functions implemented in the process and comparing the accuracy and completeness of different results (digital surface models, disparity maps and 2D displacement fields) obtained using our code and other commercial and open-source matching programs in a wide variety of application fields.

Strategic development process and complex adaptive systems

The two areas of theory upon which this research was based were „strategy development process?(SDP) and „complex adaptive systems? (CAS), as part of complexity theory, focused on human social organisations. The literature reviewed showed that there is a paucity of empirical work and theory in the overlap of the two areas, providing an opportunity for contributions to knowledge in each area of theory, and for practitioners. An inductive approach was adopted for this research, in an effort to discover new insights to the focus area of study. It was undertaken from within an interpretivist paradigm, and based on a novel conceptual framework. The organisationally intimate nature of the research topic, and the researcher?s circumstances required a research design that was both in-depth and long term. The result was a single, exploratory, case study, which included use of data from 44 in-depth, semi-structured interviews, from 36 people, involving all the top management team members and significant other staff members; observations, rumour and grapevine (ORG) data; and archive data, over a 5½ year period (2005 – 2010). Findings confirm the validity of the conceptual framework, and that complex adaptive systems theory has potential to extend strategy development process theory. It has shown how and why the strategy process developed in the case study organisation by providing deeper insights to the behaviour of the people, their backgrounds, and interactions. Broad predictions of the „latent strategy development? process and some elements of the strategy content are also possible. Based on this research, it is possible to extend the utility of the SDP model by including peoples? behavioural characteristics within the organisation, via complex adaptive systems theory. Further research is recommended to test limits of the application of the conceptual framework and improve its efficacy with more organisations across a variety of sectors.

Person-oriented and process-oriented teachers : an investigation of the links between ESOL teachers' personal belief systems and approaches to teaching

This thesis looks to two traditions in research into language teaching, teacher beliefs and classroom interaction, in order to investigate the question: Do teachers of ESOL have an identifiable and coherent system of beliefs about teaching and learning that may account for different approaches to teaching? A qualitative approach to research is taken, following a case study tradition, in order to carry out an in-depth study into the beliefs of six ESOL teachers. Five teachers participated in an initial pilot study and two subsequently became the main case studies for the research. The beliefs of a sixth teacher were then investigated to verify the findings. Semi-structured interviews and classroom observations were carried out with all the teachers. The teachers in the study were found to have personal belief systems that cohere around two orientations to teaching and learning - a person orientation and a process orientation. Moreover, the findings suggest that underlying the orientations is the perception that teachers have of their teacher identity, in terms of whether this is seen as a separate identity or as part of their personality. It is suggested that the two orientations may offer a powerful tool for teacher education as it is increasingly recognised that, in order to be effective, teacher educators must take into account the beliefs that teachers bring with them to training and development programmes. An initial investigations into the teachers’ classroom behaviour suggests that while their methodologies approach may be very similar there are fundamental differences in their interactions patterns and these differences may be a result of their own orientation. However, while teachers’ personal belief systems undoubtedly underlie their approach to teaching, further research is needed to establish the extent and the nature of the relationship between orientation and classroom interaction.

Developing and evaluating a methodology for business process improvement

Purpose – There appears to be an ever-insatiable demand from markets for organisations to improve their products and services. To meet this, there is a need to provide business process improvement (BPI) methodologies that are holistic, structured and procedural. Therefore, this paper describes research that has formed and tested a generic and practical methodology termed model-based and integrated process improvement (MIPI) to support the implementation of BPI; and to validate its effectiveness in organisations. This methodology has been created as an aid for practitioners within organisations. Design/methodology/approach – The research objectives were achieved by: reviewing and analysing current methodologies, and selecting a few frameworks against key performance indicators. Using a refined Delphi approach and semi-structured interview with the “experts” in the field. Intervention, case study and process research approach to evaluating a methodology. Findings – The BPI methodology was successfully formed and applied by the researcher and directly by the companies involved against the criteria of feasibility, usability and usefulness. Research limitations/implications – The paper has demonstrated a new knowledge on how to systematically assess a BPI methodology in practice. Practical implications – Model-based and integrated process improvement methodology (MIPI) methodology offers the practitioner (experienced and novice) a set of step-by-step aids necessary to make informed, consistent and efficient changes to business processes. Originality/value – The novelty of this research work is the creation of a holistic workbook-based methodology with relevant tools and techniques. It extends the capabilities of existing methodologies.

Limit Theorems for Regenerative Excursion Processes

This work is supported by Bulgarian NFSI, grant No. MM–704/97

Client discourses on the process of seeking same-sex couple counselling

How same-sex couples manage the process of seeking help for their relationships is an under-researched area. Twelve semi-structured interviews were conducted with 16 people who had engaged in same-sex couple counselling, and were analysed using discourse analysis. The ways in which the couples positioned themselves as part of a 'minority group', or part of a generic group of couples struggling with relationship issues, impacted on how they discussed seeking help. We conclude that counsellors and psychotherapists need to be aware of the ways in which couples construct their relationships, and mindful of the tricky navigations around similarity to, and difference from, different-sex relationships. The impact of this on couples seeking therapeutic help is considered. © 2013 Taylor & Francis.

The early career researcher's toolkit:translating tissue engineering, regenerative medicine and cell therapy products

Although the importance of translation for the development of tissue engineering, regenerative medicine and cell-based therapies is widely recognized, the process of translation is less well understood. This is particularly the case among some early career researchers who may not appreciate the intricacies of translational research or make decisions early in development which later hinders effective translation. Based on our own research and experiences as early career researchers involved in tissue engineering and regenerative medicine translation, we discuss common pitfalls associated with translational research, providing practical solutions and important considerations which will aid process and product development. Suggestions range from effective project management, consideration of key manufacturing, clinical and regulatory matters and means of exploiting research for successful commercialization.

Understanding and improving the manufacturing and changeover process in Saudi Arabian business - a multiple case study approach

The importance of the changeover process in the manufacturing industry is becoming widely recognised. Changeover is a complete process of changing between the manufacture of one product to manufacture of an alternative product until specified production and quality rates are reached. The initiatives to improve changeover exist in industry, as better changeover process typically contribute to improved quality performance. A high-quality and reliable changeover process can be achieved through implementation of continuous or radical improvements. This research examines the changeover process of Saudi Arabian manufacturing firms because Saudi Arabia’s government is focused on the expansion of GDP and increasing the number of export manufacturing firms. Furthermore, it is encouraging foreign manufacturing firms to invest within Saudi Arabia. These initiatives, therefore, require that Saudi manufacturing businesses develop the changeover practice in order to compete in the market and achieve the government’s objectives. Therefore, the aim of this research is to discover the current status of changeover process implementation in Saudi Arabian manufacturing businesses. To achieve this aim, the main objective of this research is to develop a conceptual model to understand and examine the effectiveness of the changeover process within Saudi Arabian manufacturing firms, facilitating identification of those activities that affect the reliability and high-quality of the process. In order to provide a comprehensive understanding of this area, this research first explores the concept of quality management and its relationship to firm performance and the performance of manufacturing changeover. An extensive body of literature was reviewed on the subject of lean manufacturing and changeover practice. A research conceptual model was identified based on this review, and focus was on providing high-quality and reliable manufacturing changeover processes during set-up in a dynamic environment. Exploratory research was conducted in sample Saudi manufacturing firms to understand the features of the changeover process within the manufacturing sector, and as a basis for modifying the proposed conceptual model. Qualitative research was employed in the study with semi-structured interviews, direct observations and documentation in order to understand the real situation such as actual daily practice and current status of changeover process in the field. The research instrument, the Changeover Effectiveness Assessment Tool (CEAT) was developed to evaluate changeover practices. A pilot study was conducted by examining the CEAT, proposed for the main research. Consequently, the conceptual model was modified and CEAT was improved in response to the pilot study findings. Case studies have been conducted within eight Saudi manufacturing businesses. These case studies assessed the implementation of manufacturing changeover practice in the lighting and medical products sectors. These two sectors were selected based on their operation strategy which was batch production as well as the fact that they fulfilled the research sampling strategy. The outcomes of the research improved the conceptual model, ultimately to facilitate the firms’ adoption and rapid implementation of a high-quality and reliability changeover during the set-up process. The main finding of this research is that Quality’s factors were considering the lowest levels comparing to the other factors which are People, Process and Infrastructure. This research contributes to enable Saudi businesses to implement the changeover process by adopting the conceptual model. In addition, the guidelines for facilitating implementation were provided in this thesis. Therefore, this research provides insight to enable the Saudi manufacturing industry to be more responsive to rapidly changing customer demands.