17,960 research outputs found

    Pion Charge Exchange on Deuterium

    Full text link
    We investigate quantum corrections to a classical intranuclear cascade simulation of pion single charge exchange on the deuteron. In order to separate various effects the orders of scattering need to be distinguished and, to that end, we develop signals for each order of scattering corresponding to quasi-free conditions. Quantum corrections are evaluated for double scattering and are found to be large. Global agreement with the data is good.Comment: 30 pages, 12 figure

    Under pressure: pulmonary hypertension associated with left heart disease.

    Get PDF
    © ERS 2015.Pulmonary hypertension (PH) associated with left heart disease (PH-LHD) is the most common type of PH, but its natural history is not well understood. PH-LHD is diagnosed by right heart catheterisation with a mean pulmonary arterial pressure ⩾25 mmHg and a pulmonary capillary wedge pressure >15 mmHg. The primary causes of PH-LHD are left ventricular dysfunction of systolic and diastolic origin, and valvular disease. Prognosis is poor and survival rates are low. Limited progress has been made towards specific therapies for PH-LHD, and management focuses on addressing the underlying cause of the disease with supportive therapies, surgery and pharmacological treatments. Clinical trials of therapies for pulmonary arterial hypertension in patients with PH-LHD have thus far been limited and have provided disappointing or conflicting results. Robust, long-term clinical studies in appropriate target populations have the potential to improve the outlook for patients with PH-LHD. Herein, we discuss the knowledge gaps in our understanding of PH-LHD, and describe the current unmet needs and challenges that are faced by clinicians when identifying and managing patients with this disease

    Mesospheric scatter and its microstructure

    Get PDF
    The difference in character between mesospheric returns from about 70 and about 80 km was noted. The 69-km echo is characterized by a single return with about .1 Hz width, while the 82.5 km return extends over more than 3 Hz bandwidth; this difference is also perceptible, but to a lesser degree, on the fading curves. The conclusion seems inescapable that internal random velocities of a few m/s are present within the scattering volume for the 82.5-km echo. The most likely source for these rather large velocities is convective instability arising from deformations of the temperature profile by breaking gravity waves. The distinction between the two types of scatter at these altitudes probably accounts for the behavior with frequency of the nightime fading period at low and very low frequencies. The fading period of D-region reflections at night was constant at about 7 min from 16 to 43 kHz, but that at frequencies of 70 kHz and above, the fading period decreased in such a way as to indicate the presence of irregularities smaller than about 1 km in size. This suggests that frequencies of 48 kHz and above, the fading period decreased in such a way as to indicate the presence of irregularities smaller than about 1 km in size. This suggests that frequencies of 48 kHz and below were reflected primarily from the region below 80 km where the narrow spectral irregularities dominate

    Anisotropic imbibition on surfaces patterned with polygonal posts

    Full text link
    We present and interpret lattice Boltzmann simulations of thick films spreading on surfaces patterned with polygonal posts. We show that the mechanism of pinning and depinning differs with the direction of advance, and demonstrate that this leads to anisotropic spreading within a certain range of material contact angles.Comment: DSFD Proceedings 201

    Pion double charge exchange on 4He

    Get PDF
    The doubly differential cross sections for the 4^4He(π+,π−)4p(\pi^+,\pi^-) 4p reaction were calculated using both a two-nucleon sequential single charge exchange model and an intranuclear cascade code. Final state interactions between the two final protons which were the initial neutrons were included in both methods. At incident pion energies of 240 and 270 MeV the low-energy peak observed experimentally in the energy spectrum of the final pions can be understood only if the contribution of pion production is included. The calculated cross sections are compared with data.Comment: 25 pages, 9 figure

    The evaluation of waste tyre pulverised fuel for NOx reduction by reburning

    Get PDF
    The combustion of coal for power generation will continue to play a major role in the future, however, this must be achieved using cleaner technologies than we use at present. Scrap tyre arisings in the UK are 400,000 tonnes per year amounting to 30 million tyres and in the EU as a whole, more than 2.5 million tonnes of tyres per year are scrapped. The recent EC Waste Landfill Directive (1999) sets a deadline for the banning of whole and shredded tyres from landfill sites by 2006. Consequently, there is an urgent need to find a mass disposal route for tyres. We describe, in this paper, a novel use for tyre rubber pulverised fuel in a NOx reburning process which may have an application in power station boilers. This method of disposal could represent a way of combining waste disposal, energy recovery and pollution control within one process. A preliminary study of micronised tyre combustion was undertaken to identify the suitable size ranges for application in NOx reduction by reburning. Tests were performed in a down-fired, pulverised fuel combustor (PFC) operating at about 80 kW. Superior combustion characteristics, i.e. burnout were achieved with particle sizes less than 250 μm. A South African coal was used as the primary fuel in the reburn tests and the tyre was fed pneumatically via a separate feed system. Parameters studied, were, reburn zone stoichiometry and reburn fuel fraction. Additionally, the carbon content of the ash was carefully monitored for any effect on burnout at the fuel rich reburn stoichiometries. The NOx reductions achieved with tyres are compared with reburning with coal. NOx reductions up to 80% were achieved with tyres at half of the reburn fuel feed rate required to achieve the same reductions by coal. The results have been evaluated within the context of other studies available in the literature on NOx reburning by bituminous coal, brown coal, gas and biomass

    Being in the hidden third: Insights into transdisciplinary ontology

    Get PDF
    This paper reflects two transdisciplinary (TD) scholars’ attempts to glean deeper insights into Nicolescu’s transdisciplinary ontology (i.e., multiple Levels of Reality and the Hidden Third). Respecting that Nicolescu’s Hidden Third represents the convergence of quantum physics, philosophy, and inner experiences, one TD scholar explored ‘What is it like to be in the Hidden Third?’ by expanding on Nicolescu’s constructs of cyber-space-time and transhumanism, which are grounded in quantum physics. The other TD scholar tendered philosophical insights by offering the idea of ontological emergence and the act of becoming as informed by the transcendentals. The intent was to understand ‘the being of being’ or perhaps ‘the being of becoming.’ The richness of Nicolescu’s ontological thinking offers a range of interpretation and we are grateful for the opportunity to feed off his methodological genius to respectively flourish through questions, clarification and truth seeking

    Conceptualizing a transdisciplinary nexus for addressing complex problems

    Get PDF
    We envision opening a way of perceiving the transdisciplinary Hidden Third as a transcendental nexus of both passive and active causal powers reflecting and engaged with the external structures that create the complex social realities in which we live. It is in these realities and their possible worlds that the revealing of our relational capacities and activating (actualising) potentialities occurs. We propose that innovative and co-created solutions to complex problems can emerge when something at work within each person helps very differently minded people with a stake in an issue to realise that they have capabilities and potential that can be actualised situationally. To facilitate this idea, we adopt a notion of transindividuality, which is constitutive through relationality. This is a futural process of imaginal thinking and imaginary thinking. We suggest that when temporarily functioning in an intermediate inner universe (mundus imaginalis), and by operating between the empirical (concrete facts) and the abstract (e.g., meditative thinking), active imaginal powers foster emergent solutions unbounded by the positivistic framing problems and their future consequences. We conceptualized a transdisciplinary nexus that draws from the mundus imaginalis and the Hidden Third to provide deeper insights into the role that people’s inner images of the world play when engaging in transdisciplinary problem solving
    • …
    corecore