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Articoli di riviste sul tema "Stream characterisation":
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Armstrong, Paul W., e Frans Van de Werf. "STREAM characterisation correction". Lancet 389, n. 10084 (maggio 2017): 2102. http://dx.doi.org/10.1016/s0140-6736(17)31335-1.
Reed, Grant W., e Christopher P. Cannon. "STREAM characterisation correction – Authors' reply". Lancet 389, n. 10084 (maggio 2017): 2102–3. http://dx.doi.org/10.1016/s0140-6736(17)31336-3.
Carter, James H., e Graham J. Hutchings. "Recent Advances in the Gold-Catalysed Low-Temperature Water–Gas Shift Reaction". Catalysts 8, n. 12 (5 dicembre 2018): 627. http://dx.doi.org/10.3390/catal8120627.
The low-temperature water–gas shift reaction (LTS: CO + H2O ⇌ CO2 + H2) is a key step in the purification of H2 reformate streams that feed H2 fuel cells. Supported gold catalysts were originally identified as being active for this reaction twenty years ago, and since then, considerable advances have been made in the synthesis and characterisation of these catalysts. In this review, we identify and evaluate the progress towards solving the most important challenge in this research area: the development of robust, highly active catalysts that do not deactivate on-stream under realistic reaction conditions.
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Kawashima, Nobuyuki, Lina Shi, Ning Xu, Jun Li e Andrea R. Gerson. "Characterisation of single-stream Bayer plant heat exchanger scale". Hydrometallurgy 159 (gennaio 2016): 75–86. http://dx.doi.org/10.1016/j.hydromet.2015.10.025.
Strutwolf, Jörg, Grégoire Herzog, Alexandra Homsy, Alfonso Berduque, Courtney J. Collins e Damien W. M. Arrigan. "Potentiometric characterisation of a dual-stream electrochemical microfluidic device". Microfluidics and Nanofluidics 6, n. 2 (20 giugno 2008): 231–40. http://dx.doi.org/10.1007/s10404-008-0319-z.
Ramos, P., C. Mateu, T. Antoja, A. Helmi, A. Castro-Ginard, E. Balbinot e J. M. Carrasco. "Full 5D characterisation of the Sagittarius stream with Gaia DR2 RR Lyrae". Astronomy & Astrophysics 638 (giugno 2020): A104. http://dx.doi.org/10.1051/0004-6361/202037819.
Context. The Sagittarius (Sgr) stream is one of the best tools that we currently have to estimate the mass and shape of our Galaxy. However, assigning membership and obtaining the phase-space distribution of the stars that form the tails of the stream is quite challenging. Aims. Our goal is to produce a catalogue of the RR Lyrae stars of Sgr and obtain an empiric measurement of the trends along the stream in sky position, distance, and tangential velocity. Methods. We generated two initial samples from the Gaia DR2 RR Lyrae catalogue: one selecting only the stars within ±20° of the orbital plane of Sagittarius (Strip), and the other resulting from application of the Pole Count Map (nGC3) algorithm. We then used the model-independent, deterministic method developed in this work to remove most of the contamination by detecting and isolating the stream in distance and proper motions. Results. The output is two empiric catalogues: the Strip sample (higher-completeness, lower-purity) which contains 11 677 stars, and the nGC3 sample (higher-purity, lower-completeness) with 6608 stars. We characterise the changes along the stream in all the available dimensions, namely the five astrometric dimensions plus the metallicity, covering more than 2π rad in the sky, and obtain new estimates for the apocentres and the mean [Fe/H] of the RR Lyrae population. Also, we show the first map of the two components of the tangential velocity thanks to the combination of distances and proper motions. Finally, we detect the bifurcation in the leading arm and report no significant difference between the two branches in terms of metallicity, kinematics, or distance. Conclusions. We provide the largest sample of RR Lyrae candidates of Sgr, which can be used as input for a spectroscopic follow-up or as a reference for the new generation of models of the stream through the interpolators in distance and velocity that we constructed.
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Koppelman, Helmer H., e Amina Helmi. "Time evolution of gaps in stellar streams in axisymmetric Stäckel potentials". Astronomy & Astrophysics 649 (maggio 2021): A55. http://dx.doi.org/10.1051/0004-6361/202039968.
Context. When a subhalo interacts with a cold stellar stream, the otherwise nearly smooth distribution of stars is disturbed, and this creates a gap. The properties of these gaps depend on the interaction parameters. Their characterisation could thus lead to a determination of the mass spectrum of the perturbers and might reveal the existence of dark subhalos orbiting the Milky Way. Aims. Our goal is to construct a fully analytical model of the formation and evolution of gaps embedded in streams orbiting in a realistic Milky Way potential. Methods. To this end, we extended our previous model for spherical potentials and predict the properties of gaps in streams evolving in axisymmetric Stäckel potentials. We used action-angles and their simple behaviour to calculate the divergence of initially nearby orbits that are slightly perturbed by the interaction with a subhalo. Results. Our model, corroborated by N-body experiments, predicts that the size of a gap grows linearly with time. We obtain analytical expressions for the dependences of the growth rate on the orbit of the stream, the properties of the subhalo (mass and scale radius), and the geometry of the encounter (relative velocity and impact parameter). We find that the density at the centre of the gap decreases with time as a power law in the same way as the density of a stream. This causes the density contrast between a pristine and a perturbed stream on the same orbit to asymptotically reach a constant value that only depends on the encounter parameters. Conclusions. We find that at a fixed age, smallish gaps are sensitive mostly to the mass of the subhalo, while gaps formed by subhalo flybys with a low relative velocity, or when the stream and subhalo move in parallel, are degenerate to the encounter parameters.
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Risch, Denise, Nienke van Geel, Douglas Gillespie e Ben Wilson. "Characterisation of underwater operational sound of a tidal stream turbine". Journal of the Acoustical Society of America 147, n. 4 (aprile 2020): 2547–55. http://dx.doi.org/10.1121/10.0001124.
Fritz, Ken M., e Walter K. Dodds. "Harshness: characterisation of intermittent stream habitat over space and time". Marine and Freshwater Research 56, n. 1 (2005): 13. http://dx.doi.org/10.1071/mf04244.
Frequently disturbed environments, such as intermittent streams, are ecologically useful for studying how disturbance characteristics (e.g. frequency, magnitude) affect community structure and succession. We developed a harshness index that quantifies ecologically pertinent spatial and temporal characteristics of prairie intermittent streams that may limit or reduce diversity and abundance to predict benthic macroinvertebrate assemblage characteristics. The index incorporates 11 variables that describe the hydrological regime (e.g. average flow, flow variability, drying and flooding) and distance to perennial surface water. We started with 27 variables, but removed 16 that did not increase the predictive value of the index. The relationships among index values and annual mean macroinvertebrate assemblage characteristics (taxonomic richness, diversity, evenness and abundance) were tested over two years using seven sites that represent a range of flow permanence (recent and historical), flood magnitude (recent and historical) and surface-water connectivity. Mean annual taxonomic richness was significantly related to the harshness index. Evenness and abundance were not related to harshness. Further analyses indicated that distance to the nearest permanent habitat was less important than annual or historical hydrological parameters, even though prior research had documented higher rates of colonisation at sites that were closer to nearest permanent habitat. Both annual factors that can alter abundance and colonisation immediately (e.g. floods, drought in each year) and historical factors (e.g. probability of drying, average length of dry period over decades) may influence assemblage characteristics. Historical factors may influence evolutionary adaptations of invertebrates and may predominate when relative disturbance rates are lower such as in years with less flooding.
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Ward, Sophie L., Peter E. Robins, Matt J. Lewis, Gregorio Iglesias, M. Reza Hashemi e Simon P. Neill. "Tidal stream resource characterisation in progressive versus standing wave systems". Applied Energy 220 (giugno 2018): 274–85. http://dx.doi.org/10.1016/j.apenergy.2018.03.059.
Stokes, Christopher Richard. "The geomorphology of palaeo-ice streams : identification, characterisation and implications for ice stream functioning". Thesis, University of Sheffield, 2001. http://etheses.whiterose.ac.uk/14815/.
Ice streams are the dominant drainage pathways of contemporary ice sheets and their location and behaviour are viewed as key controls on ice sheet stability. Identifying palaeo-ice streams is of paramount importance if we are to produce accurate reconstructions of former ice sheets and examine their critical role in the oceanclimate system. Many workers have invoked palaeo-ice streams from a variety of former ice sheets, despite a limited understanding of their glacial geomorphology. This thesis addresses the problem by predicting several diagnostic geomorphological criteria indicative of ice stream activity. These are developed objectively from the known characteristics of contemporary ice streams and can be summarised as: large flow-set dimensions (>20 km wide and >150 km long), highly convergent flow patterns, highly attenuated subglacial bedforms (length:width >10: 1), Boothia-type dispersal plumes, abrupt lateral margins «2 km), ice stream marginal moraines, evidence of pervasively deformed till, and submarine sediment accumulations (marine-terminating ice streams only). Collectively, the criteria are used to construct conceptual landsystems of palaeo-ice stream tracks. Using satellite imagery and aerial photography to map glacial geomorphology, identification of the criteria is used to validate the location of a previously hypothesised ice stream and identify a hitherto undetected palaeo-ice stream from the former Laurentide Ice Sheet. Implications for ice stream basal processes are explored and their ice sheet-wide significance is assessed. On Victoria Island (Arctic Canada) five of the geomorphological criteria are identified and the extent of the marine-based M'Clintock Channel Ice Stream is reconstructed at 720 km in length and 140 km in width. The ice stream (operating between 10,400 and 10,000 yr BP) was located within a broad topographic trough, but internal glaciological processes, rather than properties of the bed controlled the margin locations. It eroded into pre-existing unconsolidated sediments and left a spectacular pattern of subglacially-produced landforms, recording a snapshot view of the bed prior to ice stream shut-down. Sediment availability appears critical to its functioning (deformable bed?) and the debris flux of the ice stream is inferred to have been high. Frictional shut-down occurred once down-cutting through sediments reached hard bedrock close to the terminus. The presence of four of the geomorphological criteria are used to identify a terrestrial ice stream which drained the Keewatin Sector of the Laurentide Ice Sheet between ca. 10,000 and 8,500 yr BP. Its size is reconstructed at over 450 km in length and 140 km in width, and it left behind a subglacial bedform pattern consisting of highly attenuated drumlins (length:width ratios up to 48: 1) displaying exceptional parallel conformity. This represents an isochronous bedform pattern and variations in lineament elongation ratio are thought to be a useful proxy for ice velocity. Highest elongation ratios occur immediately downstream of a topographic step where the ice stream entered a sedimentary basin. It is inferred that the ice stream was triggered by climatic warming which altered the ice sheet configuration and the thermal state of the bed. A switch from cold to warm-based conditions probably triggered rapid basal sliding. The ice stream (and a tributary) shut down when it ran out of ice, causing widespread thinning of the ice sheet and subsequent deglaciation. These ice streams denote considerable ice sheet instability over both hard and soft (deformable) beds and emphasise the enormous effects that ice streams had in controlling the deglaciation of the Laurentide Ice Sheet.
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Tedds, Sian. "Scale model testing of tidal stream turbines : wake characterisation in realistic flow conditions". Thesis, University of Liverpool, 2014. http://livrepository.liverpool.ac.uk/18673/.
In this thesis the effect of uniform and profiled (non-uniform) steady flows on a scale-model tidal stream turbine (0.5m diameter) are experimentally investigated using the University of Liverpool high-speed recirculating water-channel. The power and thrust coefficients of the turbine with numbers of blades between two and six and various blade-pitch-angles are measured in uniform flow with low levels of turbulence at velocities ranging from 0.45m/s to 1.34m/s. With a three-bladed turbine at optimum blade-pitch-angle the power and thrust coefficients are compared in three different flow conditions of uniform flow with low turbulence intensity (2%), uniform flow with high turbulence intensity (5%) and non-uniform flow with high turbulence intensity (5%). Using an Acoustic Doppler Velocimeter (ADV) measurements of three-dimensional velocities are taken, initially, around the three-bladed turbine with optimum blade-pitch-angle. The velocities at five different heights and up to 7D downstream are probed where the upstream velocity is uniform with low turbulence levels and mean upstream velocity of 0.9m/s. Further ADV measurements are taken downstream of the three-bladed turbine through a horizontal centre-plane at lower velocities of 0.45m/s and 0.68m/s to probe the effect of Reynolds number on the turbine's wake. In addition wake measurements are taken downstream of the two-bladed turbine with optimum and non-optimum blade-pitch-angles to study the effect of differing tip-speed-ratios, thrust and power coefficients. Also the wake of the turbine support structure without blades is investigated. In a flow with high turbulence and mean velocity of 0.9m/s the wake of the three-bladed turbine is studied through a centre-plane equal to the turbine hub height. Further in a profiled flow, representative of a 1/5th velocity power law and upstream integral average velocity of 0.82m/s (over the turbine's swept area), characterisation of the flow downstream of the three-bladed turbine with optimum blade-pitch-angle is taken at five depths up to 5D downstream. These velocities are then compared in detail to those in uniform flow. Finally the ADV technique is used extensively throughout this thesis and, indeed, in most studies concerned with tidal turbine wakes. As issues regarding certain aspects of the ADV came to light during this study, the robustness of this technique is investigated by using two different ADV probe orientations and a comparison to 1D Laser Doppler Velocimetry is made.
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Joshi, Mahesh Raj. "The psychophysical characterisation of dorsal and ventral stream functions with equivalent noise paradigm normal clinical populations". Thesis, Glasgow Caledonian University, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.726786.
Ali, Liaqat. "Gold and base metal exploration studies based on mineralogical and geochemical characterisation of stream sediments from north Pakistan". Thesis, University of Exeter, 2011. http://hdl.handle.net/10036/3290.
North Pakistan represents a highly favourable area for a variety of mineral deposit types, including arc-related porphyry Cu, Au and Mo and arc and backarc epithermal precious metal deposits (Sweatman et al., 1995; PMDC, 2001). However, few deposits have been discovered in the area, mainly due to its remote nature and inaccessibility, and because of a lack of exploration tools for high altitude terrains. From stream sediment sampling campaigns by local and international organizations, including a large dataset provided by the Pakistan Mineral Development Corporation (PMDC), a significant amount of geochemical data now exists for the region. This data has been incorporated into an Arc-GIS 9.2 database, along with stream catchment and geological information, and detail of all known areas of mineralisation. From this, spatial catchment maps together with multi-element geochemical associations have been studied to delineate areas showing anomalous values for Au and base metals. The two most prospective areas were found to be the Shyok Suture Zone and northern Kohistan, with the dominant control on mineralisation being structural rather than lithological. These areas were targeted for detailed stream sediment sampling and mineralogical and geochemical analysis. From studies of Au and Au pathfinder elements in different size fractions of the stream sediments and heavy mineral concentrates (HMC), the catchments of Teru, Asheriat and Pakora (in order of decreasing rank) were identified as most prospective. Morphological and geochemical analyses of native Au grains from panned concentrates has given an indication of proximity to bedrock source (<10 km) and the possible styles of mineralisation in these catchments; porphyry Cu-type in Asheriat and Pb-Sb quartz veins in Teru and Pakora. Automated mineralogical analysis of the stream sediments (<180 µm fraction) and HMC (<180 µm), using a QEMSCANÒ system, confirmed this interpretation. The effectiveness of the developed methodologies for exploration in remote and high altitude terrains of North Pakistan is discussed, and recommendations made for future exploration.
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Cryar, Benjamin Joseph. "Characterisation of the up-stream components in the stretch-induced ERK-1/2 MAP kinase cascade in human myometrial cells". Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/9581.
The mechanisms underlying stretch-induced signalling in the human myometrium are poorly understood. Previous work in the group has demonstrated that in vitro stretch of human myometrial cells leads to increased expression of the pro-labour factors COX-2 and IL-8 via activation of the ERK-1/2 MAPK cascade, however the identities of components upstream in this pathway have yet to be elucidated. I over expressed constitutively active Ras in human myometrial cells, leading to increased ERK-1/2 phosphorylation and elevated COX-2 and IL-8 mRNA expression. I then inhibited Ras using both the chemical inhibitor manumycin A and transfection with dominant-negative mutant Ras. Each resulted in decreased ERK-1/2 phosphorylation and COX-2 expression in response to stretch. I performed immunoprecipitations to investigate which factors associated with Ras and found that stretch increased its association with SOS-1 and Grb-2. I then confirmed that Grb-2 was essential for the propagation of the stretch signal to ERK-1/2 by using siRNA to silence Grb- 2 and found that this resulted in decreased phosphorylation of ERK-1/2 and COX-2 and IL-8 protein synthesis. Silencing of SOS-1 decreased COX-2 protein expression but had little effect on ERK-1/2 phosphorylation. I then investigated the role of FAK, a constituent of stretch sensing focal adhesions, in the transduction of the stretch signal. First I used the inhibitors Y-27632 and PF-573,228, however neither inhibited the stretch-induced increase in ERK-1/2 phosphorylation or COX-2 and IL-8 mRNA expression In contrast, using siRNA to silence FAK expression reduced both the stretch-induced increase in ERK-1/2 phosphorylation and COX-2 and IL-8 protein synthesis. Moreover, transfection with dominant-negative FRNK reduced ERK-1 phosphorylation and COX-2 protein synthesis. Cells were also treated with the Src family kinase inhibitor PP-2 resulting in a decrease in stretch-induced ERK-1/2 phosphorylation and COX-2 protein synthesis. These data suggest that Ras, Grb-2 and FAK all act upstream of ERK-1/2 to mediate stretchinduced up-regulation of COX-2 and IL-8 in human myometrial cells, the role of SOS-1 is less clear, but also appears to be involved in stretch-induced expression of COX-2.
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Hardy, Louis. "Caractérisation d'une lance diphasique et étude de l'impact d'un jet ascendant sur la stratification des fumées d'incendie". Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0013.
Cette thèse s'inscrit dans un ensemble de travaux ayant pour objectif d'étudier les matériels des sapeurs-pompiers et l'effet de leurs actions de lance sur leur environnement. Ce domaine d'étude est encore nouveau avec une première étape essentielle pour les travaux présentés dans ce manuscrit effectué en 2016 avec l'approche performantielle. Nous proposons dans les trois premiers chapitres une étude comparative entre un nouveau matériel de lutte contre l'incendie, la lance diphasique, et les lances utilisées actuellement. Des expérimentations ont permis de déterminer les caractéristiques géométriques mais également l'évolution en fonction de la distance de la taille et de la vitesse des gouttes constituant le jet. Les deux derniers chapitres complètent cette approche par une étude à échelle intermédiaire des phénomènes d'interaction entre un spray et une couche de fumée en utilisant une approche couplée expérimentation/modélisation. Les essais en maquette servent à vérifier la pertinence des simulations numériques du logiciel Fire Dynamics Simulator. L'approche numérique permet de quantifier les échanges thermiques entre le jet et le milieu environnant. Une perspective de ses travaux est l'utilisation des bilans énergétiques, qui ont été établi, pour chercher à optimiser le mode d'action des sapeurs-pompiers This thesis is part of work that aims to study firefighters' equipment and the effect of their fire hose actions on their environment. This field of study is still new with a first essential step for the work presented in this manuscript carried out in 2016 with the performantial approach. In the first three chapters, we propose a comparative study between a new firefighting equipment, the twin-fluid hose, and the currently used hoses. Experiments have made it possible to determine the geometric characteristics and also the evolution of the size and speed of the drops making up the jet as a function of distance. The last two chapters complete this approach with an intermediate-scale study of the interaction phenomena between a spray and a smoke layer using a coupled experimental/modelling approach. The model tests will be used to verify the relevance of the numerical simulations of the Fire Dynamics Simulator software. The numerical approach makes it possible to quantify the heat exchange between the spray and the surrounding environment. One perspective of this work is the use of energy balances, which have been established, to seek to optimise the mode of action of firefighters
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Dawood, Ali M. "Content based processing and modelling of MPEG-1 video streams". Thesis, University of Essex, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298876.
Taylor, Hazel. "Characterisation of the primitive streak promoter of the murine Brachyury gene". Thesis, University of Warwick, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264913.
Boxall, Alistair Bruce Alleyne. "The characterisation and identification of major toxicants in streams receiving road runoff". Thesis, University of Sheffield, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387635.
Capitoli di libri sul tema "Stream characterisation":
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Vo, Dai-Viet N., e Adesoji A. Adesina. "Evaluation of Promoted Mo Carbide Catalysts for Fischer-Tropsch Synthesis: Synthesis, Characterisation, and Time-on-Stream Behaviour". In ACS Symposium Series, 155–84. Washington, DC: American Chemical Society, 2011. http://dx.doi.org/10.1021/bk-2011-1084.ch007.
Köhl, Karin I., e Rainer Lösch. "Experimental Characterisation of Metal Tolerance". In Heavy Metal Stress in Plants, 434–54. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-662-07743-6_17.
Andersen, Kristian Gjerrestad, Gbanaibolou Jombo, Sikiru Oluwarotimi Ismail, Yong Kang Chen, Hom Nath Dhakal e Yu Zhang. "Damage Characterisation in Composite Laminates Using Vibro-Acoustic Technique". In Springer Proceedings in Energy, 275–82. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-63916-7_34.
AbstractThe need to characterise in-service damage in composite structures is increasingly becoming important as composites find higher utilisation in wind turbines, aerospace, automotive, marine, among others. This paper investigates the feasibility of simplifying the conventional acousto-ultrasonic technique set-up for quick and economic one-sided in-service inspection of composite structures. Acousto-ultrasonic technique refers to the approach of using ultrasonic transducer for local excitation while sensing the material response with an acoustic emission sensor. However, this involves transducers with several auxiliaries. The approach proposed herewith, referred to as vibro-acoustic testing, involves a low level of vibration impact excitation and acoustic emission sensing for damage characterisation. To test the robustness of this approach, first, a quasi-static test was carried out to impute low-velocity impact damage on three groups of test samples with different ply stacking sequences. Next, the vibro-acoustic testing was performed on all test samples with the acoustic emission response for the samples acquired. Using the acoustic emission test sample response for all groups, the stress wave factor was determined using the peak voltage stress wave factor method. The stress wave factor results showed an inverse correlation between the level of impact damage and stress wave factor across all the test sample groups. This corresponds with what has been reported in literature for acousto-ultrasonic technique; thus demonstrating the robustness of the proposed vibro-acoustic set-up. Structural health monitoring, impact damage, acousto-ultrasonic testing, non-destructive testing.
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Schoone, Sunny, Tobias Vraetz, Ralph Baltes e Elisabeth Clausen. "Blue Nodules: Use of Acoustic Emission Technology for an Inline Characterisation of Hydraulic Material Streams". In Yearbook of Sustainable Smart Mining and Energy 2021, 213–27. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-84315-1_12.
Gibbens, R. J. "Traffic characterisation and effective bandwidths for broadband network traces". In Stochastic Networks Theory and Applications, 169–80. Oxford University PressOxford, 1996. http://dx.doi.org/10.1093/oso/9780198523994.003.0009.
Abstract The trend of current developments in telecommunication networks is towards systems which will allow a number of widely disparate traffic streams to share common resources through statistical sharing. How efficiently this can be managed depends critically upon the statistical characteristics of the traffic. Our aim in this paper is to investigate the application of a simple and robust graphical descriptor of a given traffic stream, designed to emphasise those aspects of the data that are important for the statistical sharing of common resources. Two examples considered in detail are an MPEG-1 video encoding of the Star Wars movie and traces of ethernet traffic taken at Bellcore.
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Okereafor, Godwin, Elizabeth Makhatha, Lukhanyo Mekuto e Vuyo Mavumengwana. "Mobility of Trace Element Contaminants from Abandoned Gold Mine Dump to Stream Waters in an Agricultural Active Area". In Trace Metals in the Environment - New Approaches and Recent Advances. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.90818.
In this study, the selected streams within the Blesbokspruit located in South Africa were characterised in this study. Because of prolonged mining activities coupled with ineffective management practices, several mine tailing (MT) dumps are widely distributed in this area. Metals and metalloid contamination from these tailing facilities have been reported to be major contributors to environmental hazards such as acid mine drainage (AMD). With increased agricultural activities in this area, an assessment of the general quality of water being utilised for irrigation purposes and feeding of farm animals becomes inevitable. A procedural method was implemented in a bid to identify relations between tailing and stream water contamination. Representative gold tailing sediments and water samples were collected, respectively. With the aid of X-ray fluorescence (XRF) and X-ray diffraction (XRD), the mineralogical characterisation of the tailing sediments was successfully carried out, while acid digestion using inductively coupled plasma-optical emission spectrometry (ICP-OES) was utilised in the determination of trace metal contents. Samples of different water sources were also characterised. There was a clear description of the link between tailings, water contamination and possible implications to animals and humans in the long run.
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"Characterisation of Urban Streams and Urban Flooding". In Advances in Urban Flood Management, 41–70. CRC Press, 2007. http://dx.doi.org/10.1201/9780203945988-8.
Douglas, Ian, Iain White, Nigel Lawson, Mira Kobold e Erik Pasche. "Characterisation of Urban Streams and Urban Flooding". In Advances in Urban Flood Management, 29–58. Taylor & Francis, 2007. http://dx.doi.org/10.1201/9780203945988.ch3.
Seidel, Stefan, Cedric Schirmer, Rüdiger W. Maschke, Lia Rossi, Regine Eibl e Dieter Eibl. "Computational Fluid Dynamics for Advanced Characterisation of Bioreactors Used in the Biopharmaceutical Industry: Part I: Literature Review". In Computational Fluid Dynamics - Recent Advances, New Perspectives and Applications [Working Title]. IntechOpen, 2023. http://dx.doi.org/10.5772/intechopen.109848.
Computational fluid dynamics (CFD) is a widely used tool for investigating fluid flows in bioreactors. It has been used in the biopharmaceutical industry for years and has established itself as an important tool for process engineering characterisation. As a result, CFD simulations are increasingly being used to complement classical process engineering investigations in the laboratory with spatially and temporally resolved results, or even replace them when laboratory investigations are not possible. Parameters that can be determined include the specific power input, Kolmogorov length, hydrodynamic stress, mixing time, oxygen transfer rate, and for cultivations with microcarriers, the NS1 criterion. In the first part of this series, a literature review illustrates how these parameters can be determined using CFD and how they can be validated experimentally. In addition, an overview of the hardware and software typically used for bioreactor characterisation will also be provided, including process engineering parameter investigations from the literature. In the second part of this series, the authors’ research results will be used to show how the process engineering characterisation of mechanically driven bioreactors for the biopharmaceutical industry (stirred, orbitally shaken, and wave-mixed) can be determined and validated using CFD.
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Bihan, Catherine Le, e Jacques Lefebvre. "Stability of BSA stabilised oil-in-water emulsions in relation to interfacial rheology. Influence of pH and ionic strength". In Gums and stabilisers for the Food industry 6, 389–94. Oxford University PressOxford, 1992. http://dx.doi.org/10.1093/oso/9780199632848.003.0050.
Abstract The rheological properties in shear of Bovine Serum Albumin (BSA) films adsorbed atadodecane/water interface are studied in shear at three pH’s (4, 4.8, 8) in the absence or presence of NaCl, in parallel with centrifugation-induced coalescence of BSA stabilised emulsions in similar conditions. Rheological characterisation includes the analysis of flow curves obtained in the shear rate range 2.3xl0-3-10 s-1, and of stress relaxation after shearing at 2.3xl0-3 s-1
Atti di convegni sul tema "Stream characterisation":
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Valencia, Juan D., Juan M. Mejía, Alonso Ocampo e Alejandro Restrepo. "Modelling Dispersed Chemical Droplets Injection in the Gas Stream for EOR Applications". In SPE Reservoir Characterisation and Simulation Conference and Exhibition. Society of Petroleum Engineers, 2019. http://dx.doi.org/10.2118/196620-ms.
Bracquené, Ellen, e Joost R. Duflou. "Waste stream characterisation for industrial symbiosis matchmaking: A case study for ferro metals". In PROCEEDINGS OF THE 22ND INTERNATIONAL ESAFORM CONFERENCE ON MATERIAL FORMING: ESAFORM 2019. AIP Publishing, 2019. http://dx.doi.org/10.1063/1.5112604.
Farahani, Arash, e Peter Childs. "Characterisation of Static Strip Seal Flow". In ASME Turbo Expo 2007: Power for Land, Sea, and Air. ASMEDC, 2007. http://dx.doi.org/10.1115/gt2007-27469.
Strip seals are used in gas turbine engines between two static elements or between components which do not move relative to each other, such as Nozzle Guide Vanes (NGVs). The key role of a strip seal between NGV segments is sealing between the flow through the main stream annulus and the internal air system, a further purpose is to limit the inter-segmental movements. In general the shape of the strip seal is a rectangular strip that fits into two slots in adjacent components. The minimum clearance required for static strip seals must be found by accounting for thermal expansion, misalignment, and application, to allow correct fitment of the strip seals. Any increase in leakage raises the cost due to an increase in the cooling air use, which is linked to specific fuel consumption, and it can also alter gas flow paths and performance. The narrow path within the seal assembly, especially the height has the most significant affect on leakage. The height range of the narrow path studied in this paper is 0.01–0.06 mm. The behaviour of the flow passing through the narrow path has been studied using CFD modelling and measurements in a bespoke rig. The CFD and experimental results show that normalized leakage flow increases with pressure ratio before reaching a maximum. The main aim of this paper is to provide new experimental data to verify the CFD modelling for static strip seals. The typical flow characteristics validated by CFD modelling and experiments can be used to predict the flow behaviour for future static strip seal designs.
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Frith, A. J., E. D. Dickson, J. A. Hewetson e K. McCormick. "Free Release Waste Characterisation During the Decommissioning of Windscale Pile 2 Chimney". In ASME 2003 9th International Conference on Radioactive Waste Management and Environmental Remediation. ASMEDC, 2003. http://dx.doi.org/10.1115/icem2003-4924.
The decommissioning of Windscale Pile 2 Chimney resulted in the removal of one of most historically significant and prominent features of the Sellafield site. The project was the first large scale concrete “free release” operation to be undertaken on the Sellafield nuclear site, producing 4500 tons of concrete of which 3000 tons was demonstrated to be “free release”. The paper describes the radiometric techniques employed in the characterization and segregation of the concrete into Low Level Waste (LLW), Very Low Level Waste (VLLW) and Free Release categories. It examines the robust solutions that were developed to meet the technical and regulatory challenges of the project, which included the definition of free release, the selection of averaging volumes, the testing and validation of the monitoring systems employed for bulk quantities of concrete and the identification and removal of small numbers of fuel particles from the free release waste stream. As a result of interest shown by other BNFL and UKAEA decommissioning projects at Sellafield, the paper finishes by discussing ways in which the system may be developed to assay other waste streams.
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Ramos, V., R. Carballo e John Ringwood. "Exploring the utility and effectiveness of tidal stream energy resource assessment and characterisation standards: A case study". In Proceedings of Renew 2016, 2nd International Conference on Renewable Energies Offshore. Taylor & Francis Group, 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742: CRC Press, 2016. http://dx.doi.org/10.1201/9781315229256-12.
Walsh, P. A., M. R. D. Davies e T. Dalton. "Characterisation of Stability Criteria for Pressure Driven Flows in Small Length Scale Fluidic Devices". In ASME 2005 Summer Heat Transfer Conference collocated with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems. ASMEDC, 2005. http://dx.doi.org/10.1115/ht2005-72426.
This paper develops criteria for the prediction of two distinct instabilities in microflows, one isothermal, the other with heat transfer. The engineering objective is to transport droplets that act as micro-reactors and are carried through various processes in a carrier fluid to prepare sample reactants or complete a chemical reaction. The requirement is that the carrier fluid flow be stable so that droplet trajectories can be accurately controlled. The popular two-dimensional microfluidic geometry of three streamlines merging at a junction is chosen for this analysis. A dimensional analysis of the governing flow-field and boundary conditions is undertaken to derive the non-dimensional groups upon which the flow characteristics of the junction are dependent. The emerging parameters are the Grasshof number (Gr) and Reynolds numbers (Re) of both inlet streams. Experimental flow visualisation images are used to determine the relationship between these scaling groups for both isothermal flow and buoyancy opposing mixed convection. The experimental range of inlet Re’s is from 1 to 100. It is found that the ratio of the inlet Re’s is sufficient to describe isothermal flows and that a parameter referred to as W* (the product of the Richardson number (Ri) and Re of the centreline stream) provides a good correlation for buoyancy opposing mixed convection. Inertia dominated flow regimes are seen to exist for W* values below approximately 2 and re-circulation zones are observed when W* is increased above this value. It was also observed that buckling flow was attainable at a critical Re of 65 for isothermal flow and that this critical Re is significantly reduced as W* is increased. An analogy is drawn from the results between the flow studied in this paper and that of cross flow over bluff objects such as a cylinder. Finally, based on the results of this work a design envelope is developed for predicting the stability of scaled models of the fluidic junction.
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Challita, G., R. Othman, P. Guegan, K. Khalil e A. Poitou. "Dynamic shear stress in a double lap bonded assembly". In MATERIALS CHARACTERISATION 2009. Southampton, UK: WIT Press, 2009. http://dx.doi.org/10.2495/mc090161.
BASU, INDRANIL, VÁCLAV OCELÍK e JEFF TH M. DE HOSSON. "EXPERIMENTAL DETERMINATION AND THEORETICAL ANALYSIS OF LOCAL RESIDUAL STRESS AT GRAIN SCALE". In MATERIALS CHARACTERISATION 2017. Southampton UK: WIT Press, 2017. http://dx.doi.org/10.2495/mc170011.
Sakurai, H. "Analytical solution of a two-dimensional elastostatic problem of functionally graded materials via the Airy stress function". In MATERIALS CHARACTERISATION 2011. Southampton, UK: WIT Press, 2011. http://dx.doi.org/10.2495/mc110111.
Devriese, Cedric, Simon Snijders, Ward De Paepe e Rob Bastiaans. "The Design and Optimisation of a 100% Hydrogen Micro Gas Turbine Micromix Combustor: Preliminary Hydrogen Injection Depth Characterisation Using Cold Flow Steady RANS". In ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/gt2022-80805.
Abstract In a modern electricity grid, with fluctuating renewable energy input and problems linked to construction of large power plants in densely populated areas, local, flexible, and zero-emission electricity and heat production becomes evermore important. Consequently, we research the design and optimisation of a hydrogen fuelled micro Gas Turbine (mGT). This paper focusses on our continued development and optimisation of the low-NOx hydrogen combustion chamber, based on the Micromix principle. Based on previous work, we observed that the hydrogen injection depth was critical in minimising thermal NOx formation. To characterise the hydrogen Jet in Cross Flow (JICF) mechanism more deeply, we first designed a simplified single nozzle variant of the micromix geometry. Using this test geometry, we analysed the relation between the hydrogen injection pressure and the hydrogen injection depth, perpendicularly into the air flow, using both an analytical model and cold flow steady RANS simulations. From these simulation results we obtained a preliminary optimal range for the injection pressure, so that the hydrogen does not protrude too far into the air stream (thereby increasing the residence time and increasing the possibility of higher thermal NOx formation), nor too little (thereby reducing the mixing of both fuel and air and increasing the chance of combustion too near to the wall). Based on these results, we can, using hot flow steady RANS simulations, validate the optimal hydrogen injection pressure range from the single-nozzle, cold flow results, for minimal thermal NOx formation, in a follow-up research.
Rapporti di organizzazioni sul tema "Stream characterisation":
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Stuttard, Thomas Simon. The development, testing and characterisation of a straw tracking detector and readout system for the Fermilab muon g-2 experiment. Office of Scientific and Technical Information (OSTI), gennaio 2017. http://dx.doi.org/10.2172/1484200.
