The Evaporation of Liquid Micro-Drops on the Heated Substrate

Evaporation of a heated sessile water micro-drop was studied experimentally at the substrate temperature and surrounding atmosphere from 30 to 50 0 C. The studies were performed on the float glass substrate with aluminum nanocoating of optical quality. The research has shown that the specific rate of evaporation (mass loss per unit of the drop surface area) increases with the decrease in droplet volume and at the last stage several times exceeds the initial value

Determination of the patch cords lengths distribution physical layer of the modern automation systems of smart city and smart home by the Monte Carlo method

A method for determining the distribution of patch cord lengths for the formation of the physical layer of modern IP-control systems is proposed. Assuming the formation of the switching field on a regular basis and the equiprobable connection of individual ports, a procedure was developed for determining the probability density function of the cord lengths, taking into account the necessary margin in case of unevenness of the laying. The calculation of the distribution has been performed and it is shown that it is advisable to use patch cords with a length of 1–2 m in control systems

Modeling molecular hydrogen in low metallicity galaxies

We use a suite of hydrodynamics simulations of the interstellar medium (ISM) within a galactic disk, which include radiative transfer, a non-equilibrium model of molecular hydrogen, and a realistic model for star formation and feedback, to study the structure of the ISM and H$_2$ abundance as a function of local ISM properties. We show that the star formation rate and structure of the ISM are sensitive to the metallicity of the gas with a progressively smoother density distribution with decreasing metallicity. In addition to the well-known trend of the HI-H$_2$ transition shifting to higher densities with decreasing metallicity, the maximum achieved molecular fraction in the interstellar medium drops drastically at $Z \lesssim 0.2 \, Z_\odot$ as the formation time of H$_2$ becomes much longer than a typical lifetime of dense regions of the ISM. We present accurate fitting formulae for both volumetric and projected $f_\mathrm{H_2}$ measured on different scales as a function of gas metallicity, UV radiation field, and gas density. We show that when the formulae are applied to the patches in the simulated galaxy the overall molecular gas mass is reproduced to better than a factor of $\lesssim 1.5$ across the entire range of metallicities and scales. We also show that the presented fit is considerably more accurate than any of the previous $f_\mathrm{H_2}$ models and fitting formulae in the low-metallicity regime. The fit can thus be used for modeling molecular gas in low-resolution simulations and semi-analytic models of galaxy formation in the dwarf and high-redshift regimes.Comment: 17 pages, 12 figures; submitted to Ap

Structural Modification of La[2]O[3]-TiO[2]-B Mixture After Mechanical Activation

Accelerators require development of new and more powerful installations, generating the streams of the charged particles, affecting the development of machine building industry, energy power industry and other fields of science and technology. Great attention is paid not only to the modernization of the installations, in whole, but also to their individual elements. Cathode is the most important element of the installations, generating the stream of charged particles. Using lanthanum hexaboride as a cathode material allows getting maximum efficiency of cathode assembly due to the thermodynamic and emission properties of lanthanum hexaboride. This paper studies the properties changes of lanthanum oxide mixture, titanium and boron oxides under the influence of mechanical activation to obtain the final product, based on lanthanum hexaboride and titanium diboride, corresponding to the high performance properties of the emitter. The study resulted in determination of time and frequency of mechanical activation to obtain the particles with the smallest average size of 6.3 microns for the mixture of lanthanum oxide, titanium and boron oxides powders