5,252 research outputs found

    Theory of weakly nonlinear self sustained detonations

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    We propose a theory of weakly nonlinear multi-dimensional self sustained detonations based on asymptotic analysis of the reactive compressible Navier-Stokes equations. We show that these equations can be reduced to a model consisting of a forced, unsteady, small disturbance, transonic equation and a rate equation for the heat release. In one spatial dimension, the model simplifies to a forced Burgers equation. Through analysis, numerical calculations and comparison with the reactive Euler equations, the model is demonstrated to capture such essential dynamical characteristics of detonations as the steady-state structure, the linear stability spectrum, the period-doubling sequence of bifurcations and chaos in one-dimensional detonations and cellular structures in multi- dimensional detonations

    A quantum heat engine with coupled superconducting resonators

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    We propose a quantum heat engine composed of two superconducting transmission line resonators interacting with each other via an optomechanical-like coupling. One resonator is periodically excited by a thermal pump. The incoherently driven resonator induces coherent oscillations in the other one due to the coupling. A limit cycle, indicating finite power output, emerges in the thermodynamical phase space. The system implements an all-electrical analog of a photonic piston. Instead of mechanical motion, the power output is obtained as a coherent electrical charging in our case. We explore the differences between the quantum and classical descriptions of our system by solving the quantum master equation and classical Langevin equations. Specifically, we calculate the mean number of excitations, second-order coherence, as well as the entropy, temperature, power and mean energy to reveal the signatures of quantum behavior in the statistical and thermodynamic properties of the system. We find evidence of a quantum enhancement in the power output of the engine at low temperatures.Comment: 15 pages, 14 figures, new references adde

    Resonating Experiences of Self and Others enabled by a Tangible Somaesthetic Design

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    Digitalization is penetrating every aspect of everyday life including a human's heart beating, which can easily be sensed by wearable sensors and displayed for others to see, feel, and potentially "bodily resonate" with. Previous work in studying human interactions and interaction designs with physiological data, such as a heart's pulse rate, have argued that feeding it back to the users may, for example support users' mindfulness and self-awareness during various everyday activities and ultimately support their wellbeing. Inspired by Somaesthetics as a discipline, which focuses on an appreciation of the living body's role in all our experiences, we designed and explored mobile tangible heart beat displays, which enable rich forms of bodily experiencing oneself and others in social proximity. In this paper, we first report on the design process of tangible heart displays and then present results of a field study with 30 pairs of participants. Participants were asked to use the tangible heart displays during watching movies together and report their experience in three different heart display conditions (i.e., displaying their own heart beat, their partner's heart beat, and watching a movie without a heart display). We found, for example that participants reported significant effects in experiencing sensory immersion when they felt their own heart beats compared to the condition without any heart beat display, and that feeling their partner's heart beats resulted in significant effects on social experience. We refer to resonance theory to discuss the results, highlighting the potential of how ubiquitous technology could utilize physiological data to provide resonance in a modern society facing social acceleration.Comment: 18 page

    Non-parametric comparison of histogrammed two-dimensional data distributions using the Energy Test

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    When monitoring complex experiments, comparison is often made between regularly acquired histograms of data and reference histograms which represent the ideal state of the equipment. With the larger HEP experiments now ramping up, there is a need for automation of this task since the volume of comparisons could overwhelm human operators. However, the two-dimensional histogram comparison tools available in ROOT have been noted in the past to exhibit shortcomings. We discuss a newer comparison test for two-dimensional histograms, based on the Energy Test of Aslan and Zech, which provides more conclusive discrimination between histograms of data coming from different distributions than methods provided in a recent ROOT release.The Science and Technology Facilities Council, U

    Theory of weakly nonlinear self-sustained detonations

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    We propose a theory of weakly nonlinear multidimensional self-sustained detonations based on asymptotic analysis of the reactive compressible Navier-Stokes equations. We show that these equations can be reduced to a model consisting of a forced unsteady small-disturbance transonic equation and a rate equation for the heat release. In one spatial dimension, the model simplifies to a forced Burgers equation. Through analysis, numerical calculations and comparison with the reactive Euler equations, the model is demonstrated to capture such essential dynamical characteristics of detonations as the steady-state structure, the linear stability spectrum, the period-doubling sequence of bifurcations and chaos in one-dimensional detonations and cellular structures in multidimensional detonations

    An Investment Framework To Help Equity Financiers Select Tech SMEs In Malaysia

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    The research is geared towards understanding the development cycle of technology based companies especially in the small and medium sized sector and refer to a model to help private investors in Malaysia evaluate business proposals to make funding decisions. There is always confusión when technology entrepreneurs want to evaluate the right investors to approach for fund, becuase not all specialize in funding start-ups and risky ventures. Indept investigation of past research indicates that not much have been written on venture capital financing of small and medium sized companies in Malaysia, and this work aims to shed more light and to add to literature on venture capital. Past research have failed to recommend appropriate and a simplified framework for growth firms.However, there is need to understand the relationship between investment evaluation criteria and the development cycle.The research focusses on secondary sources available from literatures on venture capital activities. Findings from this research will be of interest to investors, investees, academics and government

    Insecticidal Effect of the Extracts of Cladonia foliacea (Huds.) Willd. and Flavoparmelia caperata (L.) Hale AgainstAdults of the Grain Weevil, Sitophilus granarius (L.) (Coleoptera: Curculionidae)

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    Four different concentrations of extracts, obtained from the two lichen species (Cladonia foliacea (Huds.) Willd. and Flavoparmelia caperata (L.) Hale), were tested against the grain weevil, Sitophilus granaries (L.) under laboratory conditions. Mortality rate of adults was determined at 24, 48, and 96 h. Obtained results showed that the extracts of C. foliacea and F. caperata had insecticidal effects on the adults of S. granarius in comparison with control. The insecticidal effect was influenced by the concentration of the extract and the exposure time. Higher concentrations and longer exposure time resulted to highest toxicity levels on S. granarius. Mortality rates after 96 h of treatment with highest concentration (20 mg.ml-1) of the extracts of F. caperata and C. foliacea were determined as 91 and 83%, respectively. Bioassay revealed that 96 h LC50 values were 0.107 and 0.354 mg.ml-1, respectively. The results suggest that lichen compounds could be useful as alternatives of pesticides
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