9,356 research outputs found
The performance and application of cross flow fans for automotive engine cooling systems
No full textThe work reported centres on the application of cross flow fan units to provide forced air flow over the radiator used for engine cooling. It is shown that a cooling system in which the airflow is ducted through the vehicle would lead to a significant reduction in vehicle drag. A ducted system allows more exact prediction of performance, and can be more easily designed in conjunction with across flow fan, that has rectangular inlet and outlet sections, and an ability to form 'S', 'L' and 'U' airflow geometries. This shape advantage of the cross flow fan also allows the use of radiators with a higher aspect ratio that could in turn permit lower bonnet lines on vehicles with a further reduction in aerodynamic drag. At higher vehicle speeds adequate cooling is usually provided by ram airflow through the cooling system. An airflow by-pass arrangement controlled by a balance valve has been devised and tested. The operation of this valve was found to be stable and smooth, and extremely beneficial in reducing the total system resistance and increasing fan performance under ram airflow conditions. A computer model has been developed and a programme produced to facilitate matching of the air circuit, fan and motor. Examples illustrate the use of this in the design of a system for a 1,6 litre passenger vehicle, with maximum b.h.p. in second gear being taken as the most critical engine condition for cooling performance
Mangarara Formation: exhumed remnants of a middle Miocene, temperate carbonate, submarine channel-fan system on the eastern margin of Taranaki Basin, New Zealand
No full textThe middle Miocene Mangarara Formation is a thin (1–60 m), laterally discontinuous unit of moderately to highly calcareous (40–90%) facies of sandy to pure limestone, bioclastic sandstone, and conglomerate that crops out in a few valleys in North Taranaki across the transition from King Country Basin into offshore Taranaki Basin. The unit occurs within hemipelagic (slope) mudstone of Manganui Formation, is stratigraphically associated with redeposited sandstone of Moki Formation, and is overlain by redeposited volcaniclastic sandstone of Mohakatino Formation. The calcareous facies of the Mangarara Formation are interpreted to be mainly mass-emplaced deposits having channelised and sheet-like geometries, sedimentary structures supportive of redeposition, mixed environment fossil associations, and stratigraphic enclosure within bathyal mudrocks and flysch. The carbonate component of the deposits consists mainly of bivalves, larger benthic foraminifers (especially Amphistegina), coralline red algae including rhodoliths (Lithothamnion and Mesophyllum), and bryozoans, a warm-temperate, shallow marine skeletal association. While sediment derivation was partly from an eastern contemporary shelf, the bulk of the skeletal carbonate is inferred to have been sourced from shoal carbonate factories around and upon isolated basement highs (Patea-Tongaporutu High) to the south. The Mangarara sediments were redeposited within slope gullies and broad open submarine channels and lobes in the vicinity of the channel-lobe transition zone of a submarine fan system. Different phases of sediment transport and deposition (lateral-accretion and aggradation stages) are identified in the channel infilling. Dual fan systems likely co-existed, one dominating and predominantly siliciclastic in nature (Moki Formation), and the other infrequent and involving the temperate calcareous deposits of Mangarara Formation. The Mangarara Formation is an outcrop analogue for middle Miocene-age carbonate slope-fan deposits elsewhere in subsurface Taranaki Basin, New Zealand
Selective chlorination of CaO from titania slag by CO+Cl-2 mixtures in fluidized bed
No full text
This paper presents a facile approach to selectively decrease the CaO content in titania slag from 1.09 to 0.18 wt.% under a selective chlorination atmosphere of Cl-2 and CO. Thermodynamic analysis indicated that a predominance area exists to selectively chlorinate CaO with a low reduction potential. The intrinsic chlorination kinetics indicated that both the high partial pressure of chlorine and high temperature were advantageous to increase the chlorination selectivity,of CaO. Under the guidance of the thermodynamic and intrinsic kinetics, selective chlorination kinetics of CaO from titania slag were conducted at 1173-1273 K and were represented by the pore-blocking rate law. The present study indicated that a high concentration of reactant gases with a low reduction potential at high temperature could simultaneously overcome the inner mass transfer resistance while maintaining a high chlorination selectivity. The optimized partial pressures of Cl-2 and CO were 0.8 and 0.2 atm, respectively, and the temperature was 1273 K. (C) 2016 Elsevier B.V. All rights reserved.</p
Debris-flow erosion and deposition dynamics
No full textDebris flows are a major natural hazard in mountains world wide, because of their destructive
potential. Prediction of occurrence, magnitude and travel distance is still a scientific challenge,
and thus research into the mechanics of debris flows is still needed. Poor understanding of the
processes of erosion and deposition are partly responsible for the difficulties in predicting debrisflow
magnitude and travel distance. Even less is known about the long-term evolution of debrisflow
fans because the sequential effects of debris-flow erosion and deposition in thousands of flows
are poorly documented and hence models to simulate debris-flow fans do not exist. Here I address
the specific issues of the dynamics of erosion and deposition in single flows and over multiple
flows on debris-flow fans by terrain analysis, channel monitoring and fan evolution modeling.
I documented erosion and deposition dynamics of debris flows at fan scale using the Illgraben
debris-flow fan, Switzerland, as an example. Debris flow activity over the past three millenia in
the Illgraben catchment in south-western Switzerland was documented by geomorphic mapping,
radiocarbon dating of wood and cosmogenic exposure dating of deposits. In this specific case I
also documented the disturbance induced by two rock avalanches in the catchment resulting in
distinct patterns of deposition on the fan surface. Implications of human intervention and the
significance of autogenic forcing of the fan system are also discussed.
Quantification and understanding of erosion and deposition dynamics in debris flows at channel
scale hinges on the ability to detect surface change. But change detection is a fundamental task
in geomorphology in general. Terrestrial laser scanners are increasingly used for monitoring down
to centimeter scale of surface change resulting from a variety of geomorphic processes, as they
allow the rapid generation of high resolution digital elevation models. In this thesis procedures
were developed to measure surface change in complex topography such as a debris-flow channel. From this data high-resolution digital elevation models were generated. But data from laser
scanning contains ambiguous elevation information originating from point cloud matching, surface
roughness and erroneous measurments. This affects the ability to detect change, and results
in spatially variable uncertainties. I hence developed techniques to visualize and quantify these
uncertainties for the specific application of change detection. I demonstrated that use of data filters
(e.g. minimum height filter) on laser scanner data introduces systematic bias in change detection.
Measurement of debris-flow erosion and deposition in single events was performed at Illgraben,
where multiple debris flows are recorded every year. I applied terrestrial laser scanning
and flow hydrograph analysis to quantify erosion and deposition in a series of debris flows. Flow
depth was identified as an important control on the pattern and magnitude of erosion, whereas deposition
is governed more by the geometry of flow margins. The relationship between flow depth
and erosion is visible both at the reach scale and at the scale of the entire fan. Maximum flow depth
is a function of debris flow front discharge and pre-flow channel cross section geometry, and this
dual control gives rise to complex interactions with implications for long-term channel stability,
the use of fan stratigraphy for reconstruction of past debris flow regimes, and the predictability of
debris flow hazards.
Debris-flow fan evolution on time scales of decades up to ten thousands of years is poorly
understood because the cumulative effects of erosion and deposition in subsequent events are
rarely well documented and suitable numerical models are lacking. Enhancing this understanding
is crucial to assess the role of autogenic (internal) and allogenic (external) forcing mechanisms on
building debris-flow fans over long time scales. On short time scales understanding fan evolution
is important for debris-flow hazard assessment. I propose a 2D reduced-complexity model to
assess debris-flow fan evolution. The model is built on a broad range of qualitative and empirical
observations on debris-flow behaviour as well as on monitoring data acquired at Illgraben as part
of this thesis. I have formulated a framework of rules that govern debris-flow behaviour, and that
allows efficient implementation in a numerical simulation. The model is shown to replicate the
general behaviour of alluvial fans in nature and in flume experiments. In three applications it
is demonstrated how fan evolution modeling may improve understanding of inundation patterns,
surface age distribution and surface morphology
Variability in aerobic methane oxidation over the past 1.2 Myrs recorded in microbial biomarker signatures from Congo fan sediments
No full textMethane (CH4) is a strong greenhouse gas known to have perturbed global climate in the past, especially when released in large quantities over short time periods from continental or marine sources. It is therefore crucial to understand and, if possible, quantify the individual and combined response of these variable methane sources to natural climate variability. However, past changes in the stability of greenhouse gas reservoirs remain uncertain and poorly constrained by geological evidence. Here, we present a record from the Congo fan of a highly specific bacteriohopanepolyol (BHP) biomarker for aerobic methane oxidation (AMO), 35-aminobacteriohopane-30,31,32,33,34-pentol (aminopentol), that identifies discrete periods of increased AMO as far back as 1.2 Ma. Fluctuations in the concentration of aminopentol, and other 35-aminoBHPs, follow a pattern that correlates with late Quaternary glacial-interglacial climate cycles, with highest concentrations during warm periods. We discuss possible sources of aminopentol, and the methane consumed by the precursor methanotrophs, within the context of the Congo River setting, including supply of methane oxidation markers from terrestrial watersheds and/or marine sources (gas hydrate and/or deep subsurface gas reservoir). Compound-specific carbon isotope values of -30 ‰ to -40 ‰ for BHPs in ODP 1075 and strong similarities between the BHP signature of the core and surface sediments from the Congo estuary and floodplain wetlands from the interior of the Congo River Basin, support a methanotrophic and likely terrigenous origin of the 35-aminoBHPs found in the fan sediments. This new evidence supports a causal connection between marine sediment BHP records of tropical deep sea fans and wetland settings in the feeding river catchments, and thus tropical continental hydrology. Further research is needed to better constrain the different sources and pathways of methane emission. However, this study identifies the large potential of aminoBHPs, in particular aminopentol, to trace and, once better calibrated and understood, quantify past methane sources and fluxes from terrestrial and potentially also marine sources
Angiostrongylus cantonensis: Apoptosis of inflammatory cells induced by treatment with mebendazole
No full textOpen access self-archiving: An author study
No full textThis, our second author international, cross-disciplinary study on open access had 1296 respondents. Its focus was on self-archiving. Almost half (49%) of the respondent population have self-archived at least one article during the last three years. Use of institutional repositories for this purpose has doubled and usage has increased by almost 60% for subject-based repositories. Self-archiving activity is greatest amongst those who publish the largest number of papers. There is still a substantial proportion of authors unaware of the possibility of providing open access to their work by self-archiving. Of the authors who have not yet self-archived any articles, 71% remain unaware of the option. With 49% of the author population having self-archived in some way, this means that 36% of the total author population (71% of the remaining 51%), has not yet been appraised of this way of providing open access. Authors have frequently expressed reluctance to self-archive because of the perceived time required and possible technical difficulties in carrying out this activity, yet findings here show that only 20% of authors found some degree of difficulty with the first act of depositing an article in a repository, and that this dropped to 9% for subsequent deposits. Another author worry is about infringing agreed copyright agreements with publishers, yet only 10% of authors currently know of the SHERPA/RoMEO list of publisher permissions policies with respect to self-archiving, where clear guidance as to what a publisher permits is provided. Where it is not known if permission is required, however, authors are not seeking it and are self-archiving without it. Communicating their results to peers remains the primary reason for scholars publishing their work; in other words,
researchers publish to have an impact on their field. The vast majority of authors (81%) would willingly comply with a mandate from their employer or research funder to deposit copies of their articles in an institutional or subject-based repository. A further 13% would comply reluctantly; 5% would not comply with such a mandate
Rate Coefficients and Kinetic Isotope Effects of the XCl + Cl (X=H, D, Mu) Reactions from Ring Polymer Molecular Dynamics
No full textThe ring-polymer
molecular dynamics (RPMD) was used to calculate the thermal rate coefficients
and kinetic isotope effects of the heavy-light-heavy abstract reaction Cl + XCl
® XCl
+ Cl (X=H, D, Mu). For the Cl + HCl reaction, the excellent agreement between
the RPMD and experimental values provides a strong proof for the accuracy of
the RPMD theory. And the RPMD results also consistent with results from other theoretical
methods including improved-canonical-variational-theory and quantum dynamics. The
most novel finding is there is a double peak in Cl + MuCl reaction near the
transition state, leaving a free energy well. It comes from the mode softening
of the reaction system at the peak of the potential energy surface. Such an
explicit free energy well suggests strongly there is an observable resonance.
And for the Cl + DCl reaction, the RPMD rate coefficient again gives very
accurate results comparing with experimental values. The only exception is at
the temperature of 312.5 K, at this temperature, results from RPMD and all other
theoretical methods are close to each other but slightly lower than the experimental
value, which indicates experimental or potential energy surface deficiency.</div
Progress of international hydrogen production network for the thermochemical Cu–Cl cycle
No full textThis paper presents recent advances by an international team which is developing the thermochemical copper–chlorine (Cu–Cl) cycle for hydrogen production. Development of the Cu–Cl cycle has been pursued by several countries within the framework of the Generation IV International Forum (GIF) for hydrogen production with the next generation of nuclear reactors. Due to its lower temperature requirements in comparison with other thermochemical cycles, the Cu–Cl cycle is particularly well matched with Canada's Generation IV reactor, SCWR (Super-Critical Water Reactor), as well as other heat sources such as solar energy or industrial waste heat. In this paper, recent developments of the Cu–Cl cycle are presented, specifically involving unit operation experiments, corrosion resistant materials and system integration.Atomic Energy of Canada LimitedOntario Research Excellence FundNatural Sciences and Engineering Research Council of CanadaUniversity Network of Excellence in Nuclear Engineering (UNENE)Canada Research Chairs progra
ŻYCIE UKRYTE W SŁOWIE. "BEKSIŃSCY. PORTRET PODWÓJNY" MAGDALENY GRZEBIAŁKOWSKIEJ W ŚWIETLE POSTSTRUKTURALIZMU
No full textLife Hidden in Words. Magdalena Grzebiałkowska\u27s "Beksińscy. Portret podwójny" and Poststructuralism
The article analyzes Magdalena Grzebiałkowska\u27s biographical "Beksińscy. Portret podwójny" which focuses on the lives of Zdzisław Beksiński and Tomasz Beksiński. The author looks at the construction of the biography and its relationship to poststructuralism, which allows for an appreciation of the literary features of the book. He points to how the specificity of the content, language, a mode of narration in Grzebiałkowska\u27s book make it a full-fledged literary work itself. As such the book departs from a typical biographical scheme. Juxtaposing the book with poststructural ideas leads to the reconsideration of the role of the author in the process of shaping of a biographical narrative
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