Adiabatic compression testing - part I : historical development and evaluation of fluid dynamic processes including shock-wave considerations

Adiabatic compression testing of components in gaseous oxygen is a test method that is utilized worldwide and is commonly required to qualify a component for ignition tolerance under its intended service. This testing is required by many industry standards organizations and government agencies. This paper traces the background of adiabatic compression testing in the oxygen community and discusses the thermodynamic and fluid dynamic processes that occur during rapid pressure surges. This paper is the first of several papers by the authors on the subject of adiabatic compression testing and is presented as a non-comprehensive background and introduction.

Theoretical investigation of mechanisms of formation and interaction of nanoparticles

In this thesis an investigation into theoretical models for formation and interaction of nanoparticles is presented. The work presented includes a literature review of current models followed by a series of five chapters of original research. This thesis has been submitted in partial fulfilment of the requirements for the degree of doctor of philosophy by publication and therefore each of the five chapters consist of a peer-reviewed journal article. The thesis is then concluded with a discussion of what has been achieved during the PhD candidature, the potential applications for this research and ways in which the research could be extended in the future. In this thesis we explore stochastic models pertaining to the interaction and evolution mechanisms of nanoparticles. In particular, we explore in depth the stochastic evaporation of molecules due to thermal activation and its ultimate effect on nanoparticles sizes and concentrations. Secondly, we analyse the thermal vibrations of nanoparticles suspended in a fluid and subject to standing oscillating drag forces (as would occur in a standing sound wave) and finally on lattice surfaces in the presence of high heat gradients. We have described in this thesis a number of new models for the description of multicompartment networks joined by a multiple, stochastically evaporating, links. The primary motivation for this work is in the description of thermal fragmentation in which multiple molecules holding parts of a carbonaceous nanoparticle may evaporate. Ultimately, these models predict the rate at which the network or aggregate fragments into smaller networks/aggregates and with what aggregate size distribution. The models are highly analytic and describe the fragmentation of a link holding multiple bonds using Markov processes that best describe different physical situations and these processes have been analysed using a number of mathematical methods. The fragmentation of the network/aggregate is then predicted using combinatorial arguments. Whilst there is some scepticism in the scientific community pertaining to the proposed mechanism of thermal fragmentation,we have presented compelling evidence in this thesis supporting the currently proposed mechanism and shown that our models can accurately match experimental results. This was achieved using a realistic simulation of the fragmentation of the fractal carbonaceous aggregate structure using our models. Furthermore, in this thesis a method of manipulation using acoustic standing waves is investigated. In our investigation we analysed the effect of frequency and particle size on the ability for the particle to be manipulated by means of a standing acoustic wave. In our results, we report the existence of a critical frequency for a particular particle size. This frequency is inversely proportional to the Stokes time of the particle in the fluid. We also find that for large frequencies the subtle Brownian motion of even larger particles plays a significant role in the efficacy of the manipulation. This is due to the decreasing size of the boundary layer between acoustic nodes. Our model utilises a multiple time scale approach to calculating the long term effects of the standing acoustic field on the particles that are interacting with the sound. These effects are then combined with the effects of Brownian motion in order to obtain a complete mathematical description of the particle dynamics in such acoustic fields. Finally, in this thesis, we develop a numerical routine for the description of "thermal tweezers". Currently, the technique of thermal tweezers is predominantly theoretical however there has been a handful of successful experiments which demonstrate the effect it practise. Thermal tweezers is the name given to the way in which particles can be easily manipulated on a lattice surface by careful selection of a heat distribution over the surface. Typically, the theoretical simulations of the effect can be rather time consuming with supercomputer facilities processing data over days or even weeks. Our alternative numerical method for the simulation of particle distributions pertaining to the thermal tweezers effect use the Fokker-Planck equation to derive a quick numerical method for the calculation of the effective diffusion constant as a result of the lattice and the temperature. We then use this diffusion constant and solve the diffusion equation numerically using the finite volume method. This saves the algorithm from calculating many individual particle trajectories since it is describes the flow of the probability distribution of particles in a continuous manner. The alternative method that is outlined in this thesis can produce a larger quantity of accurate results on a household PC in a matter of hours which is much better than was previously achieveable.

Framework and processes for enhancing sustainability deliverables in Australian road infrastructure projects

Road and highway infrastructure provides the backbone for a nation’s economic growth. The versatile dispersion of population in Australia and its resource boom, coupled with improved living standards and growing societal expectations, calls for continuing development and improvement of road infrastructure under the current local, state and federal governments’ policies and strategic plans. As road infrastructure projects involve huge resources and mechanisms, achieving sustainability not only on economic scales but also through environmental and social responsibility becomes a crucial issue. While sustainability is a logical link to infrastructure development, literature study and consultation with the industry found that there is a lack of common understanding on what constitutes sustainability in the infrastructure context. Its priorities are often interpreted differently among multiple stakeholders. For road infrastructure projects which typically span over long periods of time, achieving tangible sustainability outcomes during the lifecycle of development remains a formidable task. Sustainable development initiatives often remain ideological as in macro-level policies and broad-based concepts. There were little elaboration and exemplar cases on how these policies and concepts can be translated into practical decision-making during project implementation. In contrast, there seemed to be over commitment on research and development of sustainability assessment methods and tools. Between the two positions, there is a perception-reality gap and mismatch, specifically on how to enhance sustainability deliverables during infrastructure project delivery. Review on past research in this industry sector also found that little has been done to promote sustainable road infrastructure development; this has wide and varied potential impacts. This research identified the common perceptions and expectations by different stakeholders towards achieving sustainability in road and highway infrastructure projects. Face to face interviews on selected representatives of these stakeholders were carried out in order to select and categorize, confirm and prioritize a list of sustainability performance targets identified through literature and past research. A Delphi study was conducted with the assistance of a panel of senior industry professionals and academic experts, which further considered the interrelationship and influence of the sustainability indicators, and identified critical sustainability indicators under ten critical sustainability criteria (e.g. Environmental, Health & Safety, Resource Utilization & Management, Social & Cultural, Economic, Public Governance & Community Engagement, Relations Management, Engineering, Institutional and Project Management). This presented critical sustainability issues that needed to be addressed at the project level. Accordingly, exemplar highway development projects were used as case studies to elicit solutions for the critical issues. Through the identification and integration of different perceptions and priority needs of the stakeholders, as well as key sustainability indicators and solutions for critical issues, a set of decision-making guidelines was developed to promote and drive consistent sustainability deliverables in road infrastructure projects.

Venture creation and resource processes : using Bricolage sustainability ventures

Principal Topic: Resource decisions are critical to the venture creation process, which has important subsequent impacts on venture creation and performance (Boeker, 1989). Most entrepreneurs however, suffer substantial resource constraints in venture creation and during venture growth (Shepherd et al., 2000). Little is known about how high potential, sustainability ventures (the ventures of interest in this research), despite resource constraints, achieve continued venture persistence and venture success. One promising theory that explicitly links to resource constraints is a concept developed by Levi Strauss (1967) termed bricolage. Bricolage aligns with notions of resourcefulness: using what's on hand, through making do, and recombining resources for new or novel purposes (Baker & Nelson 2005). To the best of our knowledge, previous studies have not systematically investigated internal and external constraints, their combinations, and subsequent bricolage patterns. The majority of bricolage literature focuses on external environmental constraints (e.g. Wieck 1989; Baker & Nelson 2005), thereby paying less attention to in evaluating internal constraints (e.g. skills and capabilities) or constraint combinations. In this paper we focus on ventures that typically face resource-poor environments. High potential, nascent and young sustainability ventures are often created and developed with resource constraints and in some cases, have greater resource requirements owing to higher levels of technical sophistication of their products (Rothaermel & Deeds 2006). These ventures usually have high aspirations and potential for growth who ''seeks to meet the needs and aspirations without compromising the ability to meet those of the future'' (Brundtland Commission 1983). High potential ventures are increasingly attributed with a central role in the development of innovation, and employment in developed economies (Acs 2008). Further, increasing awareness of environmental and sustainability issues has fostered demand for business processes that reduce detrimental environmental impacts of global development (Dean & McMullen 2007) and more environmentally sensitive products and services: representing an opportunity for the development of ventures that seek to satisfy this demand through entrepreneurial action. These ventures may choose to ''make do'' with existing resources in developing resource combinations that produce the least impact on the environment. The continuous conflict between the greater requirements for resources and limited resource availability in high potential sustainable ventures, with the added complexity of balancing this with an uncompromising focus on using ''what's on hand'' to lessen environment impacts may make bricolage behaviours critical for these ventures. Research into bricolage behaviour is however, the exception rather than the rule (Cunha 2005). More research is therefore needed to further develop and extend this emerging concept, especially in the context of sustainability ventures who are committed to personal and social goals of resourcefulness. To date, however, bricolage has not been studied specifically among high potential sustainable ventures. This research seeks to develop an in depth understanding of the impact of internal and external constraints and their combinations on the mechanisms employed in bricolage behaviours in differing dynamic environments. The following research question was developed to investigate this: How do internal, external resource constraints (or their combinations) impact bricolage resource decisions in high potential sustainability ventures? ---------- Methodology/Key Propositions: 6 case studies will be developed utilizing survey data from the Comprehensive Australian Study of Entrepreneurial Emergence (CAUSEE) large-scale longitudinal study of new venture start-ups in Australia. Prior to commencing case studies, 6 scoping interviews were conducted with key stakeholders including industry members, established businesses and government to ensure practical relevance in case development. The venture is considered the unit of analysis with the key informant being the entrepreneur and other management team members where appropriate. Triangulation techniques are used in this research including semi-structured interviews, survey data, onsite visits and secondary documentation website analysis, resumes, and business plans. These 6 sustainability ventures have been selected based on different environmental dynamism conditions including a traditionally mature market (building industry) and a more dynamic, evolving industry (renewable energy/solar ventures). In evaluating multidisciplinary literature, we expect the following external constraints are critical including: technology constraints (seen through lock-in of incumbents existing technology), institutional regulation and standards, access to markets, knowledge and training to nascent and young venture bricolage processes. The case studies will investigate internal constraints including resource fungability, resource combination capabilities, translating complex science/engineering knowledge into salient, valuable market propositions, i.e. appropriate market outcomes, and leveraging relationships may further influence bricolage decisions. ---------- Results and Implications: Intended ventures have been identified within the CAUSEE sample and have agreed to participate and secondary data collection for triangulation purposes has already commenced. Data collection of the case studies commenced 27th of May 2009. Analysis is expected to be completed finalised by 25th September 2009. This paper will report on the pattern of resource constraints and its impact on bricolage behaviours: its subsequent impact on resource deployment within venture creation and venture growth. As such, this research extends the theory of bricolage through the systematic analysis of constraints on resource management processes in sustainability ventures. For practice, this research may assist in providing a better understanding of the resource requirements and processes needed for continued venture persistence and growth in sustainability ventures. In these times of economic uncertainty, a better understanding of the influence on constraints and bricolage: the interplay of behaviours, processes and outcomes may enable greater venture continuance and success.

Bootstrap approaches for estimation and confidence intervals of long term memory processes

In this work, we investigate an alternative bootstrap approach based on a result of Ramsey [F.L. Ramsey, Characterization of the partial autocorrelation function, Ann. Statist. 2 (1974), pp. 1296-1301] and on the Durbin-Levinson algorithm to obtain a surrogate series from linear Gaussian processes with long range dependence. We compare this bootstrap method with other existing procedures in a wide Monte Carlo experiment by estimating, parametrically and semi-parametrically, the memory parameter d. We consider Gaussian and non-Gaussian processes to prove the robustness of the method to deviations from normality. The approach is also useful to estimate confidence intervals for the memory parameter d by improving the coverage level of the interval.

How Novices Model Business Processes

In this paper, we examine the design of business process diagrams in contexts where novice analysts only have basic design tools such as paper and pencils available, and little to no understanding of formalized modeling approaches. Based on a quasi-experimental study with 89 BPM students, we identify five distinct process design archetypes ranging from textual to hybrid, and graphical representation forms. We also examine the quality of the designs and identify which representation formats enable an analyst to articulate business rules, states, events, activities, temporal and geospatial information in a process model. We found that the quality of the process designs decreases with the increased use of graphics and that hybrid designs featuring appropriate text labels and abstract graphical forms are well-suited to describe business processes. Our research has implications for practical process design work in industry as well as for academic curricula on process design.