132 research outputs found

    Collaborative Systems Thinking: Towards an Understanding of Team-level Systems Thinking

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    As the engineering workforce ages, skills with long development periods are lost with retiring individuals faster than are younger engineers developing the skills. Systems thinking is one such skill. Recent research, (Davidz 2006), has shown the importance of experiential learning in systems thinking skill development. However, an engineering career begun today has fewer program experiences than in past decades because of extended program lifecycles and a reduction in the number of new large-scale engineering programs. This pattern is clearly visible in the aerospace industry, which (Stephens 2003) cites as already experiencing a systems thinking shortage. The ongoing research outlined in this paper explores systems thinking as an emergent property of teams. Collaborative systems thinking, a term coined by the authors to denote teamlevel systems thinking, may offer an opportunity to leverage and develop a skill in short supply by concentrating on the team in addition to the individual. This paper introduces the proposed definition for collaborative systems thinking, as developed by the authors, and the outlines the structure and progress of ongoing case research into the role of organizational culture and standard process usage in the development of collaborative systems thinking

    Marine Monitoring Program: Annual Report for inshore pesticide monitoring 2018–19

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    [Extract] This component of the Marine Monitoring Program provides an understanding of nearshore pesticide profiles and the exposure risk to marine organisms, as a part of water quality condition on the Great Barrier Reef. Data are collected from eleven fixed monitoring sites located in four Natural Resource Management regions — the Wet Tropics (five sites: Low Isles, High Island, Normanby Island, Dunk Island and Lucinda), Burdekin (one site: Barratta Creek), Mackay-Whitsundays (four sites: Repulse Bay, Flat Top Island, Sandy Creek and Sarina Inlet) and Fitzroy (one site: North Keppel Island). The suite of pesticides monitored includes photosystem II (PSII) inhibiting herbicides (such as diuron, atrazine (and its metabolites), ametryn, hexazinone, tebuthiuron), which all affect photosynthesis, and are commonly detected due to their high usage in adjacent catchments, and their high solubility. Other pesticides monitored include those that have non-photosynthetic effects (such as imidacloprid and metolachlor) and knockdown herbicides (such as 2,4-D)

    Turbulent thermal diffusion in a multi-fan turbulence generator with the imposed mean temperature gradient

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    We studied experimentally the effect of turbulent thermal diffusion in a multi-fan turbulence generator which produces a nearly homogeneous and isotropic flow with a small mean velocity. Using Particle Image Velocimetry and Image Processing techniques we showed that in a turbulent flow with an imposed mean vertical temperature gradient (stably stratified flow) particles accumulate in the regions with the mean temperature minimum. These experiments detected the effect of turbulent thermal diffusion in a multi-fan turbulence generator for relatively high Reynolds numbers. The experimental results are in compliance with the results of the previous experimental studies of turbulent thermal diffusion in oscillating grids turbulence (Buchholz et al. 2004; Eidelman et al. 2004). We demonstrated that turbulent thermal diffusion is an universal phenomenon. It occurs independently of the method of turbulence generation, and the qualitative behavior of particle spatial distribution in these very different turbulent flows is similar. Competition between turbulent fluxes caused by turbulent thermal diffusion and turbulent diffusion determines the formation of particle inhomogeneities.Comment: 9 pages, 9 figure, REVTEX4, Experiments in Fluids, in pres

    Current-Use Pesticides in New Zealand Streams: Comparing Results From Grab Samples and Three Types of Passive Samplers

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    New Zealand uses more than a ton of pesticides each year; many of these are mobile, relatively persistent, and can make their way into waterways. While considerable effort goes into monitoring nutrients in agricultural streams and programs exist to monitor pesticides in groundwater, very little is known about pesticide detection frequencies, concentrations, or their potential impacts in New Zealand streams. We used the ‘Polar Organic Chemical Integrative Sampler’ (POCIS) approach and grab water sampling to survey pesticide concentrations in 36 agricultural streams in Waikato, Canterbury, Otago and Southland during a period of stable stream flows in Austral summer 2017/18. We employed a new approach for calculating site-specific POCIS sampling rates. We also tested two novel passive samplers designed to reduce the effects of hydrodynamic conditions on sampling rates: the ‘Organic-Diffusive Gradients in Thin Films’ (o-DGT) aquatic passive sampler and microporous polyethylene tubes (MPTs) filled with Strata-X sorbent. Multiple pesticides were found at most sites; two or more were detected at 78% of sites, three or more at 69% of sites, and four or more at 39% of sites. Chlorpyrifos concentrations were the highest, with a maximum concentration of 180 ng/L. Concentrations of the other pesticides were generally below 20 ng/L. Mean concentrations of individual pesticides were not correlated with in-stream nutrient concentrations. The majority of pesticides were detected most frequently in POCIS, presumably due to its higher sampling rate and the relatively low concentrations of these pesticides. In contrast, chlorpyrifos was most frequently detected in grab samples. Chlorpyrifos concentrations at two sites were above the 21-day chronic ‘No Observable Effect Concentration’ (NOEC) values for fish and another two sites had concentrations greater than 50% of the NOEC. Otherwise, concentrations were well-below NOEC values, but close to the New Zealand Environmental Exposure Limits in several cases

    Tuning the binding affinity and selectivity of perfluoroaryl-stapled peptides by cysteine-editing.

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    A growing number of approaches to 'staple' α-helical peptides into a bioactive conformation using cysteine cross-linking are emerging. Here we explore the replacement of L-cysteine with 'cysteine analogues' in combinations of different stereochemistry, side chain length and beta-carbon substitution, to examine the influence that the thiol-containing residue(s) has on target protein-binding affinity in a well explored model system, p53-MDM2/MDMX. In some cases, replacement of one or more L-cysteine residues afforded significant changes in the measured binding affinity and target selectivity of the peptide. Computationally constructed homology models indicate that some modifications, such as incorporating two D-cysteines favourably alter the positions of key functional amino acid side chains, which is likely to cause changes in binding affinity, in agreement with measured SPR data

    Direct Numerical Simulation of Turbulent Heat Transfer Modulation in Micro-Dispersed Channel Flow

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    The object of this paper is to study the influence of dispersed micrometer size particles on turbulent heat transfer mechanisms in wall-bounded flows. The strategic target of the current research is to set up a methodology to size and design new-concept heat transfer fluids with properties given by those of the base fluid modulated by the presence of dynamically-interacting, suitably-chosen, discrete micro- and nano- particles. We run Direct Numerical Simulation (DNS) for hydrodynamically fully-developed, thermally-developing turbulent channel flow at shear Reynolds number Re=150 and Prandtl number Pr=3, and we tracked two large swarms of particles, characterized by different inertia and thermal inertia. Preliminary results on velocity and temperature statistics for both phases show that, with respect to single-phase flow, heat transfer fluxes at the walls increase by roughly 2% when the flow is laden with the smaller particles, which exhibit a rather persistent stability against non-homogeneous distribution and near-wall concentration. An opposite trend (slight heat transfer flux decrease) is observed when the larger particles are dispersed into the flow. These results are consistent with previous experimental findings and are discussed in the frame of the current research activities in the field. Future developments are also outlined.Comment: Pages: 305-32
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