5,799 research outputs found

    Continuous wavelet transform and neural network for condition monitoring of rotodynamic machinery

    Get PDF
    This paper describes a novel method of rotodynamic machine condition monitoring using a wavelet transform and a neural network. A continuous wavelet transform is applied to the signals collected from accelerometer. The transformed images are then extracted as unique characteristic features relating to the various types of machine conditions. In the experiment, four types of machine operating conditions have been investigated: a balanced shaft; an unbalanced shaft, a misaligned shaft and a defective bearing. The back propagation neural network (BPNN) is used as a tool to evaluate the performance of the proposed method. The experimental results result in a recognition rate of 90 percent

    Carbon mineralogy and crystal chemistry

    Get PDF
    Carbon, element 6, displays remarkable chemical flexibility and thus is unique in the diversity of its mineralogical roles. Carbon has the ability to bond to itself and to more than 80 other elements in a variety of bonding topologies, most commonly in 2-, 3-, and 4-coordination. With oxidation numbers ranging from āˆ’4 to +4, carbon is observed to behave as a cation, as an anion, and as a neutral species in phases with an astonishing range of crystal structures, chemical bonding, and physical and chemical properties. This versatile element concentrates in dozens of different Earth repositories, from the atmosphere and oceans to the crust, mantle, and core, including solids, liquids, and gases as both a major and trace element (Holland 1984; Berner 2004; Hazen et al. 2012). Therefore, any comprehensive survey of carbon in Earth must consider the broad range of carbon-bearing phases. / The objective of this chapter is to review the mineralogy and crystal chemistry of carbon, with a focus primarily on phases in which carbon is an essential element: most notably the polymorphs of carbon, the carbides, and the carbonates. The possible role of trace carbon in nominally acarbonaceous silicates and oxides, though potentially a large and undocumented reservoir of the mantle and core (Wood 1993; Jana and Walker 1997; Freund et al. 2001; McDonough 2003; Keppler et al. 2003; Shcheka et al. 2006; Dasgupta 2013; Ni and Keppler 2013; Wood et al. 2013), is not considered here. Non-mineralogical carbon-bearing phases treated elsewhere, including in this volume, include C-O-H-N aqueous fluids (Javoy 1997; Zhang and Duan 2009; Jones et al. 2013; Manning et al. 2013); silicate melts (Dasgupta et al. 2007; Dasgupta 2013; Manning et al. 2013); carbonate melts (Cox 1980; Kramers et al. 1981; Wilson and Head 2007; Walter et al. 2008; Jones et al. 2013); a rich variety of organic molecules, including methane and higher hydrocarbons (McCollom and Simoneit 1999; Kenney et al. 2001; Kutcherov et al. 2002; Sherwood-Lollar et al. 2002; Scott et al. 2004; Helgeson et al. 2009; McCollom 2013; Sephton and Hazen 2013); and subsurface microbial life (Parkes et al. 1993; Gold 1999; Chapelle et al. 2002; Dā€™Hondt et al. 2004; Roussel et al. 2008; Colwell and Dā€™Hondt 2013; Schrenk et al. 2013; Meersman et al. 2013; Anderson et al. 2013). / The International Mineralogical Association (IMA) recognizes more than 380 carbon-bearing minerals (http://rruff.info/ima/), including carbon polymorphs, carbides, carbonates, and a variety of minerals that incorporate organic carbon in the form of molecular crystals, organic anions, or clathrates. This chapter reviews systematically carbon mineralogy and crystal chemistry, with a focus on those phases most likely to play a role in the crust. Additional high-temperature and high-pressure carbon-bearing minerals that may play a role in the mantle and core are considered in the next chapter on deep carbon mineralogy (Oganov et al. 2013)

    Monitoring Impacts of Urbanisation and Industrialisation on Air Quality in the Anthropocene Using Urban Pond Sediments

    Get PDF
    This is the final version of the article. Available from Frontiers Media via the DOI in this record.The release of toxic atmospheric pollutants since the Industrial Revolution is a major global challenge, driving climate change and damaging human health. Spatial health inequalities highlight the need to explore air pollution in different localities throughout the Anthropocene. Air quality monitoring programmes are spatially and temporally limited. We show how suitable urban sediment archives provide site specific records of long-term particulate matter (PM) releases, in cities and urban landscapes, that are or have been subjected to high pollution levels. High-resolution PM records spanning from the mid-20th century were reconstructed from an urban pond in Chongqing, southwest China, one of the fastest growing Chinese urban centres in the late 20th century. Temporal variations in pollution proxies including geomagnetic, geochemical and spheroidal carbonaceous particle trends correspond to key phases of industrial and urban developments, that are representative of the locality. Observed increases in air pollution proxies post-1960 coincide with the location of military-related industries to Chongqing and industrial intensification. Post-1997 pollution mirrors rapid urbanisation that occurred following the designation of Chongqing as a government-controlled municipality at this time and reveals a steadily increasing pollution trend to present day (2015). In comparison to Chongqing, an atmospheric depositional history was constructed from an urban pond in the Merseyside region of northwest England that has experienced a legacy of contamination since the early 19th century. In northwest England, changing characteristics of pollution are related to the establishment of localised, modern industries, power generation, urban sprawl, increased combustion-derived pollution post-1990 and effective pollution legislations. Whereas a reduction in air pollution has occurred post-2000 in Merseyside, in Chongqing, however, air pollution has continued to increase in spite of national efforts in pollution control. These urban sediments reveal the changing nature of air pollution in different urban landscapes, allowing us to assess air quality impacts of progressive industrial activity, increased road and air travel, urban expansion and the efficacy of pollution controls. It appears that air pollution remains an inevitable consequence of global industrialisation. It is therefore crucial to understand pollution histories in densely populated urban regions to determine environmental burdens of pollution on health over generational timescales.This research was supported by Halton Primary Care Trust (grant number CHCRD001 SE02), Edge Hill University (fund codes: RDWOR04, RDWOR05, RDWOR06, and RDWOR209), and the University of Exeter

    Self-management in early-stage dementia: a pilot randomised controlled trial of the efficacy and cost-effectiveness of a self-management group intervention (the SMART study).

    Get PDF
    Published onlineJournal ArticleRandomized Controlled TrialResearch Support, Non-U.S. Gov'tBACKGROUND: The possibility of living well with a long-term condition has been identified as centrally relevant to the needs of people living with dementia. Growing numbers of people with early-stage dementia are contributing accounts that emphasise the benefits of actively engaging in managing the condition. Self-management interventions share the common objectives of educating about the condition, optimising well-being, enhancing control over the situation and enabling people to take more responsibility for managing the condition. Benefits of such an approach can include improved knowledge, self-efficacy, health status, and better performance of self-management behaviours. However, there is only preliminary evidence that people with early-stage dementia can benefit from such interventions. METHODS: This feasibility study involves the development of a self-management group intervention for people with early-stage Alzheimer's disease, vascular dementia or mixed Alzheimer's and vascular dementia. This study is a single-site pilot randomised-controlled trial. Forty-two people with early stage dementia, each with a caregiver (family member/friend), will be randomised to either the self-management group intervention or to treatment as usual.The self-management group intervention will involve eight weekly sessions, each lasting 90 minutes, held at a memory clinic in North Wales. All participants will be re-assessed three and six months post-randomisation. This study is intended to supply an early evaluation of the self-management intervention so that a full scale trial may be powered from the best available evidence. It will assess the feasibility of the intervention, the study design and the recruitment strategies. It will estimate the parameters and confidence intervals for the research questions of interest. The primary outcome of interest is the self-efficacy score of the person with dementia at three months post-randomisation. Secondary outcomes for the person with dementia are self-efficacy at six months post-randomisation and cognitive ability, mood and well-being at three and six months post-randomisation. Secondary outcomes for caregivers are their distress and stress at three and six months post-randomisation. The cost-effectiveness of the intervention will also be examined. DISCUSSION: This study will provide preliminary information about the feasibility, efficacy and cost-effectiveness of a self-management group intervention for people in the early stages of dementia. TRIAL REGISTRATION: Current Controlled Trials, ISRCTN02023181.NISCHRERDF Ireland Wales Programme 2007ā€“13National Health ServiceHigher Education Funding Council for Wale

    Detection of negative pickup ions at Saturn's moon Dione

    Get PDF
    We investigate a possible negative ion feature observed by the Cassini Plasma Spectrometer (CAPS) during a flyby of Saturn's moon Dione that occurred on April 7, 2010. By examining possible particle trajectories, we find that the observed particles are consistent with negative pickā€up ions originating near the moon's surface. We find that the mass of the negative pickā€up ions is in the range of 15 ā€“ 25 u and tentatively identify this species as Oā€, likely resulting from ionization and subsequent pickā€up from Dione's O2ā€CO2 exosphere. Our estimates show that the negative ion density is ~3 x 10ā€3 cmā€3. This is comparable to, but slightly smaller than, that previously reported for the density of O2+ pickā€up ions for the same flyby, indicating that negative pickā€up ions may represent a major loss channel for Dione's exosphere

    Differential attraction in mosquito-human interactions and implications for disease control: Differential attraction to mosquitoes

    Get PDF
    Mosquito-borne diseases are a major burden on human health worldwide and their eradication through vector control methods remains challenging. In particular, the success of vector control interventions for targeting diseases such as malaria is under threat, in part due to the evolution of insecticide resistance, while for other diseases effective control solutions are still lacking. The rate at which mosquitoes encounter and bite humans is a key determinant of their capacity for disease transmission. Future progress is strongly reliant on improving our understanding of the mechanisms leading to a mosquito bite. Here, we review the biological factors known to influence the attractiveness of mosquitoes to humans, such as body odour, the skin microbiome, genetics and infection by parasites. We identify the knowledge gaps around the relative contribution of each factor, and the potential links between them, as well as the role of natural selection in shaping vector-host-parasite interactions. Finally, we argue that addressing these questions will contribute to improving current tools and the development of novel interventions for the future. This article is part of the theme issue 'Novel control strategies for mosquito-borne diseases'

    Delayed maximum northern European summer temperatures during the Last Interglacial as a result of Greenland Ice Sheet melt

    Get PDF
    This is the author accepted manuscript. The final version is available from the Geological Society of America via the DOI in this record.Here we report a new quantitative mean July temperature reconstruction using non-biting midges (chironomids) from the Danish Last Interglacial (LIG) site Hollerup (spanning 127ā€“116 ka). We find that peak mean July temperatures of 17.5 Ā°C, similar to those of the present day (1961ā€“1990 CE), were reached shortly before the onset of the regional Carpinus pollen zone. Through comparison to terrestrial and marine sequences we demonstrate that peak summer warmth took place some three millennia after the onset of LIG warming in Europe, a marked delay in line with records from the North Atlantic. Crucially, the warmest northern European summer temperatures appear to follow maximum Greenland Ice Sheet mass loss, implying that meltwater substantially reduced Atlantic Meridional Overturning Circulation and depressed European temperatures during the early part of the interglacial.Turney and Fogwill thank the Australian Research Council (grants FL100100195, FT120100004, LP120200724). Thanks to BjĆørn Buchardt for providing the C:N data, Angela Self for help with statistical analysis, David Campbell and Alan Bedford for laboratory work, and three reviewers for their constructive comments

    Aggregates in blood filter chambers used from the plasma donations of anti-D donors: evaluation for monoclonal antibody discovery using phage display.

    Full text link
    BACKGROUND: RhD-immunoglobulin (RhIg) prevents anti-D alloimmunisation in D-negative pregnant women when the fetus is D-positive, reducing the incidence of haemolytic disease of the fetus and newborn. Manufacturing RhIg is reliant on the limited supply of plasma donations with anti-D antibodies. Monoclonal antibody (mAb) development platforms such as phage display, require blood samples to be collected from anti-D donors, which may be a complicated process. The blood filter chamber (BFC) discarded after an anti-D donor's donation might provide a source of Ig-encoding RNA. This study aims to evaluate whether used BFCs are a suitable source of Ig-encoding RNA for phage display. MATERIAL AND METHODS: Haemonetics PCS2 BFCs were obtained from 10 anti-D donors for total RNA extraction, cDNA synthesis and amplification of VH and VL IgG sequences for assembly of single-chain variable fragments (scFvs). A scFv-phage display library was constructed and 3 rounds of biopanning were performed using D-positive and D-negative red blood cells (RBCs). Positive phage clones were isolated, Sanger sequenced and, where possible, reformatted into full-length human IgGs to define specificity. The BFC aggregates from 2 anti-D donors underwent a Wright-Giemsa stain and hematological cell count. RESULTS: Of 10 BFCs, a sufficient yield of total RNA for library construction was obtained from BFCs containing cellular aggregates (n=5). Aggregate analysis showed lymphocytes were the cellular source of Ig-encoding RNA. From the 5 samples with aggregates, scFvs were assembled from amplified IgG variable regions. The library constructed from 1 of these samples resulted in the isolation of clones binding to D-positive RBCs with IGHV3 gene usage. Of the 4 reformatted IgG, 3 were anti-D and 1 had undefined specificity. DISCUSSION: BFC aggregates are a new and convenient source of Ig-encoding RNA which can be used to construct Ig gene libraries for mAb isolation and discovery via antibody phage display

    Early warnings and missed alarms for abrupt monsoon transitions

    Get PDF
    Journal ArticlePalaeo-records from China demonstrate that the East Asian Summer Monsoon (EASM) is dominated by abrupt and large magnitude monsoon shifts on millennial timescales, switching between periods of high and weak monsoon rains. It has been hypothesized that over these timescales, the EASM exhibits two stable states with bifurcation-Type tipping points between them. Here we test this hypothesis by looking for early warning signals of past bifurcations in speleothem Ī“18O records from Sanbao Cave and Hulu Cave, China, spanning the penultimate glacial cycle. We find that although there are increases in both autocorrelation and variance preceding some of the monsoon transitions during this period, it is only immediately prior to the abrupt monsoon shift at the penultimate deglaciation (Termination II) that statistically significant increases are detected. To supplement our data analysis, we produce and analyse multiple model simulations that we derive from these data. We find hysteresis behaviour in our model simulations with transitions directly forced by solar insolation. However, signals of critical slowing down, which occur on the approach to a bifurcation, are only detectable in the model simulations when the change in system stability is sufficiently slow to be detected by the sampling resolution of the data set. This raises the possibility that the early warning "alarms" were missed in the speleothem data over the period 224-150 kyr and it was only at the monsoon termination that the change in the system stability was sufficiently slow to detect early warning signals
    • ā€¦
    corecore