957 resultados para Plantar pressures
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At the 2012 CDIO conference, it was clear to all that engineering for 21st Century challenges and opportunities will be critical to the success of society over the next 2-3 decades, in dealing with pressures including climate change, resource depletion and urban densification. Within this context there is a growing imperative for rapid curriculum renewal towards education for sustainable development across all types and disciplines of engineering education, around the world. Building on a paper presented by these authors at the 2012 CDIO conference, this 2013 roundtable will draw on participants’ experiences to discuss how sustainability knowledge and skills can be embedded within a CDIO-based program using a holistic approach to curriculum renewal. The highly interactive and dynamic session will include two parts: 1) a short presentation from the chairs of the roundtable on an emergent model for rapid curriculum renewal; and 2) a facilitated discussion with participants about challenges and opportunities for action. Session notes will be recorded for distribution among participants following the conference.
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In this paper, the inherent mechanism of social benefits associated with smart grid development is examined based on the pressure state response (PSR) model from resource economics. The emerging types of technology brought up by smart grid development are regarded as pressures. The improvements of the performance and efficiency of power system operation, such as the enhanced capability of accommodating renewable energy generation, are regarded as states. The effects of smart grid development on society are regarded as responses. Then, a novel method for evaluating social benefits from smart grid development is presented. Finally, the social benefits from smart grid development in a province in northwest China are carried out by using the developed evaluation system, and reasonable evaluation results are attained.
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Aim To evaluate emergency nurse practitioner service effectiveness on outcomes related to quality of care and service responsiveness. Background Increasing service pressures in the emergency setting have resulted in the adoption of service innovation models; the most common and rapidly expanding of these is the emergency nurse practitioner. The delivery of high quality patient care in the emergency department is one of the most important service indicators to be measured in health services today. The rapid uptake of emergency nurse practitioner service in Australia has outpaced the capacity to evaluate this model in outcomes related to safety and quality of patient care. Design Pragmatic randomized controlled trial at one site with 260 participants. Methods This protocol describes a definitive prospective randomized controlled trial, which will examine the impact of emergency nurse practitioner service on key patient care and service indicators. The study control will be standard emergency department care. The intervention will be emergency nurse practitioner service. The primary outcome measure is pain score reduction and time to analgesia. Secondary outcome measures are waiting time, number of patients who did not wait, length of stay in the emergency department and representations within 48 hours. Discussion Scant research enquiry evaluating emergency nurse practitioner service on patient effectiveness and service responsiveness exists currently. This study is a unique trial that will test the effectiveness of the emergency nurse practitioner service on patients who present to the emergency department with pain. The research will provide an opportunity to further evaluate emergency nurse practitioner models of care and build research capacity into the workforce.
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Addresses often unanswered questions about the costs and benefits of resource-based development The first book to offer a suitably comprehensive critique of Western Australia's development path Provides a multi-facetted perspective thanks to its truly cross-disciplinary and cross-institutional authorship Globalisation and rapid social and environmental change in recent decades have brought into sharper focus not only the benefits but also the costs of economic development. The once assumed link between economic development and societal well-being is being increasingly questioned in the face of growing social and environmental problems and unfulfilled expectations concerning political and commercial decision-makers. The orthodox development dogma is being tested in particular in resource-based economies such as Western Australia, where globalisation pressures and the concomitant rise in the demand for natural resources highlight the difficulties of effectively balancing broader societal interests with those of industry and the state. This book provides a critical review of the socio-political, environmental and cultural state of play in Western Australia, offering an analysis of how resource-based developments are shaping the state and its people.
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Aims Although suctioning is a standard airway maintenance procedure, there are significant associated risks, such as loss of lung volume due to high negative suction pressures. This study aims to assess the extent and duration of change in end-expiratory level (EEL) resulting from endotracheal tube (ETT) suction and to examine the relationship between EEL and regional lung ventilation in ventilated preterm infants with respiratory distress syndrome. Methods A prospective observational clinical study of the effect of ETT suction on 20 non-muscle-relaxed preterm infants with respiratory distress syndrome (RDS) on conventional mechanical ventilation was conducted in a neonatal intensive care unit. Ventilation distribution was measured with regional impedance amplitudes and EEL using electrical impedance tomography. Results ETT suction resulted in a significant increase in EEL post-suction (P < 0.01). Regionally, anterior EEL decreased and posterior EEL increased post-suction, suggesting heterogeneity. Tidal volume was significantly lower in volume-guarantee ventilation compared with pressure-controlled ventilation (P = 0.04). Conclusions ETT suction in non-muscle-relaxed and ventilated preterm infants with RDS results in significant lung volume increase that is maintained for at least 90 min. Regional differences in distribution of ventilation with ETT suction suggest that the behaviour of the lung is heterogeneous in nature.
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The occurrence of extreme water level events along low-lying, highly populated and/or developed coastlines can lead to devastating impacts on coastal infrastructure. Therefore it is very important that the probabilities of extreme water levels are accurately evaluated to inform flood and coastal management and for future planning. The aim of this study was to provide estimates of present day extreme total water level exceedance probabilities around the whole coastline of Australia, arising from combinations of mean sea level, astronomical tide and storm surges generated by both extra-tropical and tropical storms, but exclusive of surface gravity waves. The study has been undertaken in two main stages. In the first stage, a high-resolution (~10 km along the coast) hydrodynamic depth averaged model has been configured for the whole coastline of Australia using the Danish Hydraulics Institute’s Mike21 modelling suite of tools. The model has been forced with astronomical tidal levels, derived from the TPX07.2 global tidal model, and meteorological fields, from the US National Center for Environmental Prediction’s global reanalysis, to generate a 61-year (1949 to 2009) hindcast of water levels. This model output has been validated against measurements from 30 tide gauge sites around Australia with long records. At each of the model grid points located around the coast, time series of annual maxima and the several highest water levels for each year were derived from the multi-decadal water level hindcast and have been fitted to extreme value distributions to estimate exceedance probabilities. Stage 1 provided a reliable estimate of the present day total water level exceedance probabilities around southern Australia, which is mainly impacted by extra-tropical storms. However, as the meteorological fields used to force the hydrodynamic model only weakly include the effects of tropical cyclones the resultant water levels exceedance probabilities were underestimated around western, northern and north-eastern Australia at higher return periods. Even if the resolution of the meteorological forcing was adequate to represent tropical cyclone-induced surges, multi-decadal periods yielded insufficient instances of tropical cyclones to enable the use of traditional extreme value extrapolation techniques. Therefore, in the second stage of the study, a statistical model of tropical cyclone tracks and central pressures was developed using histroic observations. This model was then used to generate synthetic events that represented 10,000 years of cyclone activity for the Australia region, with characteristics based on the observed tropical cyclones over the last ~40 years. Wind and pressure fields, derived from these synthetic events using analytical profile models, were used to drive the hydrodynamic model to predict the associated storm surge response. A random time period was chosen, during the tropical cyclone season, and astronomical tidal forcing for this period was included to account for non-linear interactions between the tidal and surge components. For each model grid point around the coast, annual maximum total levels for these synthetic events were calculated and these were used to estimate exceedance probabilities. The exceedance probabilities from stages 1 and 2 were then combined to provide a single estimate of present day extreme water level probabilities around the whole coastline of Australia.
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A multiscale, multiphase thermokinetic model is used to show the effective control of the growth orientation of thin Si NWs for nanoelectronic devices enabled by nanoscale plasma chemistry. It is shown that very thin Si NWs with [110] growth direction can nucleate at much lower process temperatures and pressures compared to thermal chemical vapor deposition where [111]-directed Si NWs are predominantly grown. These findings explain a host of experimental results and offer the possibility of energy- and matter-efficient, size- and orientation-controlled growth of [110] Si NWs for next-generation nanodevices.
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Graphene grown on metal catalysts with low carbon solubility is a highly competitive alternative to exfoliated and other forms of graphene, yet a single-layer, single-crystal structure remains a challenge because of the large number of randomly oriented nuclei that form grain boundaries when stitched together. A kinetic model of graphene nucleation and growth is developed to elucidate the effective controls of the graphene island density and surface coverage from the onset of nucleation to the full monolayer formation in low-pressure, low-temperature CVD. The model unprecedentedly involves the complete cycle of the elementary gas-phase and surface processes and shows a precise quantitative agreement with the recent low-energy electron diffraction measurements and also explains numerous parameter trends from a host of experimental reports. These agreements are demonstrated for a broad pressure range as well as different combinations of precursor gases and supporting catalysts. The critical role of hydrogen in controlling the graphene nucleation and monolayer formation is revealed and quantified. The model is generic and can be extended to even broader ranges of catalysts and precursor gases/pressures to enable the as yet elusive effective control of the crystalline structure and number of layers of graphene using the minimum amounts of matter and energy.
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Thunderstorm downbursts are important for wind engineers as they have been shown to produce the design wind speeds for mid to high return periods in many regions of Australia [1]. In structural design codes (e.g. AS/NZS1170.02-02) an atmospheric boundary layer (ABL) is assumed, and a vertical profile is interpolated from recorded 10 m wind speeds. The ABL assumption is however inaccurate when considering the complex structure of a thunderstorm outflow, and its effects on engineered structures. Several researchers have shown that the downburst, close to its point of divergence is better represented by an impinging wall jet profile than the traditional ABL. Physical modelling is the generally accepted approach to estimate wind loads on structures and it is therefore important to physically model the thunderstorm downburst so that its effects on engineered structures may be studied. An advancement on the simple impinging jet theory, addressed here is the addition of a pulsing mechanism to the jet which allows not only the divergent characteristics of a downburst to be produced, but also it allows the associated leading ring vortex to be developed. The ring vortex modelling is considered very important for structural design as it is within the horizontal vortex that the largest velocities occur [2]. This paper discusses the flow field produced by a pulsed wall jet, and also discusses the induced pressures that this type of flow has on a scaled tall building.
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The wind loading on most structural elements is made up of both an external and internal pressure. Internal pressures are also important for the design of naturally ventilated buildings. The internal pressure is the interaction between the external pressure propagating through the building envelope and any internal plant causing building pressurization. Although the external pressure field can be well defined through a series of wind tunnel tests, modeling complexities makes accurate prediction of the internal pressure difficult. For commercial testing for the determination of design cladding pressures, an internal pressure coefficient is generally assumed from wind loading standards. Several theories regarding the propagation of internal pressures through single and multiple dominant openings have been proposed for small and large flexible buildings (Harris (1990), Holmes, (1979), Liu & Saathoff (1981 ), Vickery (1986, 1994), Vickery & Bloxham (1992), Vickery & Georgiou (1991))...
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Multiscale, multiphase numerical modeling is used to explain the mechanisms of effective control of chirality distributions of single-walled carbon nanotubes in direct plasma growth and suggest effective approaches to further improvement. The model includes an unprecedented combination of the plasma sheath, ion/radical transport, species creation/loss, plasma–surface interaction, heat transfer, surface/bulk diffusion, graphene layer nucleation, and bending/lift-off modules. It is shown that the constructive interplay between the plasma and the Gibbs–Thomson effect can lead to the effective nucleation and lift-off of small graphene layers on small metal catalyst nanoparticles. As a result, much thinner nanotubes with narrower chirality distributions can nucleate at much lower process temperatures and pressures compared to thermal CVD. This approach is validated by a host of experimental results, substantially reduces the amounts of energy and atomic matter required for the nanotube growth, and can be extended to other nanoscale structures and materials systems, thereby nearing the ultimate goal of energy- and matter-efficient nanotechnology.
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This review paper presents historical perspectives, recent advances and future directions in the multidisciplinary research field of plasma nanoscience. The current status and future challenges are presented using a three-dimensional framework. The first and the largest dimension covers the most important classes of nanoscale objects (nanostructures, nanofeatures and nanoassemblies/nanoarchitectures) and materials systems, namely carbon nanotubes, nanofibres, graphene, graphene nanoribbons, graphene nanoflakes, nanodiamond and related carbon-based nanostructures; metal, silicon and other inorganic nanoparticles and nanostructures; soft organic nanomaterials; nano-biomaterials; biological objects and nanoscale plasma etching. In the second dimension, we discuss the most common types of plasmas and plasma reactors used in nanoscale plasma synthesis and processing. These include low-temperature non-equilibrium plasmas at low and high pressures, thermal plasmas, high-pressure microplasmas, plasmas in liquids and plasma–liquid interactions, high-energy-density plasmas, and ionized physical vapour deposition as well as some other plasma-enhanced nanofabrication techniques. In the third dimension, we outline some of the 'Grand Science Challenges' and 'Grand Socio-economic Challenges' to which significant contributions from plasma nanoscience-related research can be expected in the near future. The urgent need for a stronger focus on practical, outcome-oriented research to tackle the grand challenges is emphasized and concisely formulated as from controlled complexity to practical simplicity in solving grand challenges.
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Characteristics of electrical breakdown of a planar magnetron enhanced with an electromagnet and a hollow-cathode structure, are studied experimentally and numerically. At lower pressures the breakdown voltage shows a dependence on the applied magnetic field, and the voltage necessary to achieve the self-sustained discharge regime can be significantly reduced. At higher pressures, the dependence is less sensitive to the magnetic field magnitude and shows a tendency of increased breakdown voltage at the stronger magnetic fields. A model of the magnetron discharge breakdown is developed with the background gas pressure and the magnetic field used as parameters. The model describes the motion of electrons, which gain energy by passing the electric field across the magnetic field and undergo collisions with neutrals, thus generating new bulk electrons. The electrons are in turn accelerated in the electric field and effectively ionize a sufficient amount of neutrals to enable the discharge self-sustainment regime. The model is based on the assumption about the combined classical and near-wall mechanisms of electron conductivity across the magnetic field, and is consistent with the experimental results. The obtained results represent a significant advance toward energy-efficient multipurpose magnetron discharges.
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Structural stability, electronic, and optical properties of InN under high pressure are studied using the first-principles calculations. The lattice constants and electronic band structure are found consistent with the available experimental and theoretical values. The pressure of the wurtzite-to-rocksalt structural transition is 13.4 GPa, which is in an excellent agreement with the most recent experimental values. The optical characteristics reproduce the experimental data thus justifying the feasibility of our theoretical predictions of the optical properties of InN at high pressures.
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This article quantifies the effect of the operating pressure of the H 2 + C 2H 4 gas mixture on the current density and threshold voltage of the electron emission from dense forests of multiwalled carbon nanotubes synthesized using thermal catalytic Chemical Vapor Deposition under near atmospheric pressure process conditions. The results suggest that in the pressure range of interest 400-700 Torr the field emission properties can be substantially improved by operating the process at lower gas pressures when the nanostructure aspect ratios are higher. The obtained threshold voltage ∼1.75 V/μm and the emission current densities ∼10 mA/cm 2 offer competitive advantages compared with the results reported by other authors. Copyright