907 resultados para Multi-Photon Processes
Resumo:
The importance of applying unsaturated soil mechanics to geotechnical engineering design has been well understood. However, the consumption of time and the necessity for a specific laboratory testing apparatus when measuring unsaturated soil properties have limited the application of unsaturated soil mechanics theories in practice. Although methods for predicting unsaturated soil properties have been developed, the verification of these methods for a wide range of soil types is required in order to increase the confidence of practicing engineers in using these methods. In this study, a new permeameter was developed to measure the hydraulic conductivity of unsaturated soils using the steady-state method and directly measured suction (negative pore-water pressure) values. The apparatus is instrumented with two tensiometers for the direct measurement of suction during the tests. The apparatus can be used to obtain the hydraulic conductivity function of sandy soil over a low suction range (0-10 kPa). Firstly, the repeatability of the unsaturated hydraulic conductivity measurement, using the new permeameter, was verified by conducting tests on two identical sandy soil specimens and obtaining similar results. The hydraulic conductivity functions of the two sandy soils were then measured during the drying and wetting processes of the soils. A significant hysteresis was observed when the hydraulic conductivity was plotted against the suction. However, the hysteresis effects were not apparent when the conductivity was plotted against the volumetric water content. Furthermore, the measured unsaturated hydraulic conductivity functions were compared with predictions using three different predictive methods that are widely incorporated into numerical software. The results suggest that these predictive methods are capable of capturing the measured behavior with reasonable agreement.
Resumo:
Bactrocera dorsalis sensu stricto, B. papayae, B. philippinensis and B. carambolae are serious pest fruit fly species of the B. dorsalis complex that predominantly occur in south-east Asia and the Pacific. Identifying molecular diagnostics has proven problematic for these four taxa, a situation that cofounds biosecurity and quarantine efforts and which may be the result of at least some of these taxa representing the same biological species. We therefore conducted a phylogenetic study of these four species (and closely related outgroup taxa) based on the individuals collected from a wide geographic range; sequencing six loci (cox1, nad4-3′, CAD, period, ITS1, ITS2) for approximately 20 individuals from each of 16 sample sites. Data were analysed within maximum likelihood and Bayesian phylogenetic frameworks for individual loci and concatenated data sets for which we applied multiple monophyly and species delimitation tests. Species monophyly was measured by clade support, posterior probability or bootstrap resampling for Bayesian and likelihood analyses respectively, Rosenberg's reciprocal monophyly measure, P(AB), Rodrigo's (P(RD)) and the genealogical sorting index, gsi. We specifically tested whether there was phylogenetic support for the four 'ingroup' pest species using a data set of multiple individuals sampled from a number of populations. Based on our combined data set, Bactrocera carambolae emerges as a distinct monophyletic clade, whereas B. dorsalis s.s., B. papayae and B. philippinensis are unresolved. These data add to the growing body of evidence that B. dorsalis s.s., B. papayae and B. philippinensis are the same biological species, which poses consequences for quarantine, trade and pest management.
Resumo:
Energy prices are highly volatile and often feature unexpected spikes. It is the aim of this paper to examine whether the occurrence of these extreme price events displays any regularities that can be captured using an econometric model. Here we treat these price events as point processes and apply Hawkes and Poisson autoregressive models to model the dynamics in the intensity of this process.We use load and meteorological information to model the time variation in the intensity of the process. The models are applied to data from the Australian wholesale electricity market, and a forecasting exercise illustrates both the usefulness of these models and their limitations when attempting to forecast the occurrence of extreme price events.
Resumo:
Packaged software is pre-built with the intention of licensing it to users in domestic settings and work organisations. This thesis focuses upon the work organisation where packaged software has been characterised as one of the latest ‘solutions’ to the problems of information systems. The study investigates the packaged software selection process that has, to date, been largely viewed as objective and rational. In contrast, this interpretive study is based on a 21⁄2 year long field study of organisational experiences with packaged software selection at T.Co, a consultancy organisation based in the United Kingdom. Emerging from the iterative process of case study and action research is an alternative theory of packaged software selection. The research argues that packaged software selection is far from the rationalistic and linear process that previous studies suggest. Instead, the study finds that aspects of the traditional process of selection incorporating the activities of gathering requirements, evaluation and selection based on ‘best fit’ may or may not take place. Furthermore, even where these aspects occur they may not have equal weight or impact upon implementation and usage as may be expected. This is due to the influence of those multiple realities which originate from the organisational and market environments within which packages are created, selected and used, the lack of homogeneity in organisational contexts and the variously interpreted characteristics of the package in question.
Resumo:
Project work has grown significantly in volume and recognition in recent decades as projects have ‘become a common form of work organization in all sectors of the economy’ (Lindgren & Packendorff, 2006: 841). This increase in project-based work is just one of the many changes that have been affecting the nature of work, the employment relationship and the associated conceptualization and experience of careers (Baruch, 2004b; Söderlund & Bredin, 2006). A career can be defined as a process of development along a path of work experience and roles in one or more organizations (Baruch & Rosenstein, 1992), and careers involving project-based work take place within multi layered institutional settings. Projects are generally undertaken by small temporary organizations (Ekstedt, Lundin, Söderholm & Wirdenius, 1999; Pettigrew, 2003; Söderlund, 2012) which in turn may form part of larger, permanent entities; involve people drawn from a number of disciplines and organizations; or be formed as partnerships, joint ventures or strategic alliances between two or more organizations (Scott, 2007).
Resumo:
Within a growing awareness of design as central to the strategic success and the sustained competitive advantage of firms, this paper examines how companies pursue design driven innovation (Verganti, 2008, 2009) and respond to design led innovation initiatives (Matthews & Bucolo 2013). Specifically, this paper reports the findings of a collaborative research project where CEO sponsored senior managers from five multi-national organisations, met regularly over a twelve-month period, to discuss their progress on applying a design led approach in their firms. This longitudinal research project traced the process and progress of change instigated by the senior management representatives, as well as the deeper investigation of the barriers and challenges to re-frame design more strategically in their organisation. Data were collected through workshops and interviews throughout the twelve-month period, regarding the firms’ journeys and also the barriers and challenges firms faced in order to become design led. The findings present a novel set of implications for both designers and management scholars. This paper seeks to contribute to research and practice by investigating the processes and outcomes of a design led innovation program and to propose implications for practice for designers and management.
Resumo:
This paper aims to contribute to an understanding of what actually takes place during consulting engagements. It draws on data collected from a qualitative case study of eight engagements by a niche consultancy in Australia to describe how consultants actively engage boundary crossing processes to address knowledge boundaries encountered during formal interactions with clients. While consultants actively managed knowledge boundary processes during interactions, by applying techniques such as evoking an ‘ideal state’ for clients, the engagements also yielded many missed opportunities for knowledge transformation.