This paper is the first half of a two-part publication. In these papers the well-known low Mach number edge tone configuration is investigated which is one of the canonical selfsustained flow configurations leading to simple aeroacoustic flow phenomena. The configuration consist of a planar free jet that impinges on a wedge shaped object. Under certain circumstances the jet starts to oscillate more or less periodically thereby creating an oscillating force on the wedge that acts as a dipole sound source. This first part contains a detailed literature overview and the qualitative discussion of the authors' results of a detailed parametric study. The formulae in the literature describing the dependence of the frequency on exit velocity and nozzle-wedge distance show a broad scatter, although similar in form. In this paper a systematic and thorough study is made by experimental and numerical means and remarkable agreement is found.

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The bifurcation structure of a periodically driven spherical gas/vapour bubble is examined by means of methods of nonlinear analysis. The study of Behnia and his coworkers [1] revealed that the bifurcation structures with the pressure amplitude of the excitation as control parameter are structurally similar provided that R E ω is kept constant. In the present paper, this problem is revisited. Analytical and numerical investigations of the bubble oscillator, which is the Keller-Miksis equation, are presented. It is shown that the validity range of Behnia's condition is governed by the viscosity and the surface tension, and holds only for relatively large bubbles. In water, the effect of viscosity is negligible, and the surface tension plays significant role at bubble size lower than approximately 5 µm.

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In this paper, two scenarios for the formation of shrimp-shaped domains [1] are presented. The employed test model is the Keller-Miksis equation that is a second order, harmonically forced nonlinear oscillator describing the dynamics of a single spherical gas bubble placed in a liquid domain. The results have shown that with an increasing dissipation rate (liquid viscosity), shrimp-shaped domains are evolved within the complex structure of each subharmonic resonances in the amplitude-frequency parameter plane of the external forcing. The mechanism is the coalescence and interaction of two pairs of a period-doubling and a saddle-node codimension-two bifurcation curves.

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In this paper, we present the main parts of a complete lung diagnostic system using digital tomosynthesis, and the first results obtained analyzing real tomosynthesis (DTS) images. In a DTS system first coronal image slices are reconstructed from projections using iterative and MITS reconstruction algorithms. Nodule detection is based on 2D image processing on the separated slice images, and a joint further analysis of the 2D results. We propose efficient, domain-specific filters for the enhancement and classification of bright, rounded structures. Also we develop a vessel enhancing algorithm based on strain energy filters. Vessel enhancement is required because most of the false positive findings come from nodule-like vessel shadows in the images. To reduce false positive findings SVM-based classifiers are applied, where features obtained from the vessel enhancement module are used as inputs. The system was evaluated on the first DTS scans, obtained from our experimental DTS system. The database contains ~2000 nodule candidates. 97% of nodules could be detected, while producing on average 31 false positives per scan. Keywords-Digital tomosynthesis (DTS), CAD, lung nodule detection, lung diagnostic systemThis work was partly sponsored by the project of Ministry of National Development under KMR-12-1-2012-0122.This full text paper was peer-reviewed at the direction of IEEE Instrumentation and Measurement Society prior to the acceptance and publication.978-1-4799-6477-2/15/$31.00 ©2015 IEEE

A parameter identification technique of an underlying bubble model of an experimentally observed single bubble in a cluster under dual-frequency external forcing is presented. The measurements are carried out via high-speed camera recordings at a rate of 162750 frames per second. The used frequencies during the experiment are 25 kHz and 50 kHz. With a digital image processing technique, the measured bubble radius as a function of time is determined. The employed governing equation for the parameter fitting is the Keller–Miksis equation being a second order ordinary differential equation. The unknown four-dimensional parameter space is composed by the two pressure amplitudes, the phase shift of the dual-frequency driving and the equilibrium size of the bubble. In order to obtain an optimal parameter set within reasonable time, an in-house initial value problem solver is used running on a graphics processing unit (GPU). The error function measuring the distance between the numerical simulations and the measurement is based on the identification of the maximum bubble radii during each subsequent period of the external forcing. The results show a consistent estimation of both pressure amplitudes. The optima of phase shift and equilibrium bubble size are less significant due to a valley-like shape of the error function. Nevertheless, reasonable values are found that lead to estimations of pressure and temperature peaks during bubble collapse.