Study of the heat flux fluctuations intensity during flow around a circular cylinder

An experimental study performed in an air channel using gradient heatmetry is presented, for a configuration of three heated circular cylinders with different distance between them. Cylinders were installed one by one. The main objective is to analyze the heat flux fluctuations, employing gradient heat flux sensor. The behavior of the flow in the wake behind the first cylinder under various regimes, for the specified configuration, changes the fluctuations level at the surface of the second and third cylinders. By visualizing the flow using PIV, it was possible to see areas of stagnation, separation points and other features of flow around the model. The results showed that the fluctuations level for the second cylinder is an order of magnitude lower than for the first. We can say that the first cylinder stabilizes the flow. However, at the third cylinder, this level is comparable and even higher than on the first. Use of gradient heatmetry thus made it possible for the first time to estimate the fluctuating nature of the flow and heat transfer around cylinders.

PENGURANGAN INTENSITAS FLUKTUASI TEKANAN PADA PEMBESARAN MENDADAK ALIRAN UDARA – AIR SEARAH HORISONTAL DENGAN PENEMPATAN RING

This research aims to reduce the effect of pressure fluctuations intensity on the sudden expansion of two phase flow of air - water in the same direction with the horizontal placement of the ring. Measurements done by installing a differential pressure transducer device that is placed on pressure points before and after sudden expansion. Output voltage signal recorded by a digital storage osciloscope. Tests conducted on water discharge 0.000038 m 3 / s; 0.000078 m 3 / s; 0.000116 m 3 / s; 0.000154 m 3 / s; 0.000198 m 3 / s; 0.000244 m 3 / s; 0.000284 m 3 / s and air flow 0.000065 m 3 / s; 0.00013 m 3 / s; 0.000195 m 3 / s; 0.000255 m 3 / s; 0.00032 m 3 / s; 0.000385 m 3 / s; 0.00045 m 3 / s. Results showed that if the total mass flow rate increases the pressure drop increases. Installation of the ring can reduce the pressure fluctuations intensity, the most effective installation of the ring using the ring the same diameter. Flow path is generally slug and plug flow pattern.

Intermittency and Changing Stability of Oxidative Activity of DNA in Chromosomes Inside Living Cells for Medical Diagnostics

We analyze the experimental data on fluorescence of DNA complexes inside neutrophils in flow cytometry with nanometer spatial resolution. Fluorescence visualizes oxidative activity of DNA and unusual statistics for DNA complex of full set of chromosomes. The exponential increasing of high-order central moments for fluctuations of fluorescence intensity characterizes the existence of intermittency in oxidative activity of DNA. Intermittency depends on the scales (on rank) of DNA networks in given cells. In the large-scale networks (with the scales[Formula: see text][Formula: see text][Formula: see text]12% size of the cells), here occurs the switching to the exponential decreasing of high-order central moments for fluctuations intensity, i.e. stable oxidative activity of DNA as it is assumed for small-scale gene networks. Distributions of Hölder’s averages and high-order moments for fluctuations intensity depend on the health status and can be used for high sensitive diagnostics of health. Intermittency of large-scale correlations reflects general natural property of DNA activity and immune response on various perturbations. Intermittency reflects the mutual actions of all large-scale correlations in dense fractal networks for DNA activity and synchronization of all excitations and correlations of all chromosomes in the cells.

Effects of Medium Characteristics on Laser RCS of Airplane with E-Wave Polarization

Plane wave incidence should be postulated to have an authentic target detection. Practically, the plane wave is incapable usually of keeping its power in the far field especially when propagating through an inhomogeneous medium. Consequently, we assume an incident beam wave with a finite width around the target. In this work, we calculate numerically a laser radar cross section (LRCS) of conducting targets having smooth cross sections with inflection points such as airplane in random media. Effects of fluctuations intensity of random media on the LRCS performance are studied in this paper. E-wave polarization (E-wave incidence) is considered while the mean target size is approximately twice the wavelength.