Diagnostics of Advanced Power Intensive Power Sources Based on the Acoustic Spectroscopy Method

Objective of this article is to develop a method for lithium chemical current sources diagnostics, which would ensure high reliability in assessing their technical state (primarily, the discharge degree) close to potentially achievable introduction of the acoustic spectroscopy method. Today, microcalorimetric studies and methods of impedance and noise spectroscopy make it possible to predict the lithium chemical current sources service life. However, implementation of the microcalorimetric studies result requires a lot of time accompanied by using stationary and large-size equipment, which is practically impossible in the autonomous conditions. Application of the impedance spectroscopy method provides satisfactory results only with high degrees of discharge. In the range of 0--30 %, it is very difficult to determine the discharge degree, since noticeable alteration in the correlate within its deviation from the mean value is missing. In this regard, it is proposed in order to provide diagnostics of the lithium chemical current sources in the region of initial degrees of discharge to introduce the noise diagnostics method. In order to increase reliability of the diagnostic estimates, it is advisable to use acoustic spectroscopy as a physically independent method in diagnosing the state of lithium chemical current sources. Results of the preliminary measurements analysis confirm the prospects of using the acoustic spectroscopy method in assessing the current state of primary lithium chemical current sources. Experimental studies of the lithium chemical current sources response to acoustic (mechanical) action made it possible to determine a set of parameters characterizing the proposed methodological approach. This provided a possibility to search for correlation dependences of the lithium chemical current sources spectral characteristics on the degree of their discharge. This makes it possible to use the method of acoustic spectroscopy in prompt and reliable diagnostics of the primary current sources in the region of low discharge degrees

Conducting Medium Electrical Conductivity at High Current Density

The experimental research example of electrical characteristics of structurally heterogeneous thinlayer conductors (nickel, copper) at high current density (108--109 А/m2) is shown. This current density in conditions of the samples intensive cooling is sufficient for the process of irreversible, nonthermally activated deformation. The experiment results show that the conducting medium at high current density has essential nonlinearities expressed in nonlinear dependence of the samples electrical resistance from current density. With repeated current treatments of the samples the conductors' electrical resistivity decreases. The number of defects removed from the volume of material as a result of nickel foil treatment by electric current is estimated. It is shown that under conditions of highdensity direct electric current flow in microvolumes of homogeneous and inhomogeneous conducting media a volume charge can appear. The appearance of the volume charge in a conducting medium can be caused by interaction forces during the motion of electrons and ions. Due to the interaction forces between ions and electrons of basic material and impurities, additional local ionization occurs which is realized in nano-volumes of a conductor. In the case of heterogeneous medium, the volume charge depends on the nature of the specific conductivity distribution. In a homogeneous conductor the volume charge is proportional to the square of the current density in the sample

Analytical Study of Heat Transfer When Heating or Cooling a Limited Volume of Liquid

The paper shows the results of analytical studies of heat transfer when heating or cooling a limited volume of liquid. The purpose of the research was to determine the size of the heat transfer surface, with the initial parameters of the coolants, the final temperature in the reactor and its thermal equivalent, as well as the flow rate of the second coolant through the heat exchanger corresponding to the water equivalent at a given cooling time τo. Moreover, if intensive mixing is carried out in the vessel, i.e., if the temperature of the second heat carrier practically does not change along the length of the heat transfer surface, then W2 → ∞. The solution was based on the Laplace --- Carson integral transform. The exact solution was converted for special cases of heat transfer. In particular, it should be noted that in many practical cases formulas give a fairly good approximation to the exact solution. Only at low values of the heat transfer coefficient, as well as when the volume occupied by the coolant inside the heat exchanger is commensurate with the volume of the liquid contained in the vessel, it is necessary to apply the given exact solution

Third Harmonic Generation by Focusing Femtosecond Radiation with a Wavelength of 1032 nm in Air

In open publications the results of research on the third harmonic generation in the air by femtosecond laser radiation are presented. Most of the studies have been carried out using a titanium-sapphire laser with a central emission wavelength of 800 nm. This work presents for the first time the results of studies of the third harmonic generation in the air from laser radiation with a wavelength of 1032 nm. The source of the laser radiation was an ytterbium femtosecond laser which generated pulses with duration of ~ 250 fs and a repetition rate of 1 kHz. The average output power of the laser reached 1750 mW. Maximum peak intensity of excitation laser radiation was up to 10 TW/cm2. When focusing the laser radiation its filamentation took place and was accompanied by generation of the third harmonic radiation at wavelength of 344 nm. Spectral, energy and spatial characteristics of the generated third harmonic radiation were investigated. Energy measurements were carried out up to the threshold power of pump radiation at which the competing nonlinear processes in the circuit optical elements of the experimental setup began to occur. The maximum average third harmonic emission power was 1.52 mW with a third harmonic conversion efficiency of about 0.085 %. The far-field beam pattern had a symmetric Gaussian profile with a radiation divergence of 0.11 mrad which corresponds to the diffraction quality of the beam (M2 ≈ 1)

Genetic Inactivation of D-Amino Acid Oxidase Genes in Methylotrophic Yeast Hansenula Polymorpha

Cellular D-amino acid oxidases (ODA-FAD containing flavoproteins) are widely used in biotechnology. In this regard, it is of particular interest to investigate the functional role of the composition and regulation of individual ODA genes. The aim of this work was to investigate physiological and biochemical characteristics of ODA genes of strain DL1x Hansenula (O.) polymorpha in vivo using gene knockout methodology as well as to determine the nature of these genes expression and regulation of ODA activity as a function of nitrogen and carbon source composition in the cultivation medium. H. polymorpha is a thermotolerant methylotrophic yeast. They are used to study the mechanisms of peroxisomal biogenesis and degradation, regulation of methanol metabolism, nitrate assimilation and stress response. A serial dilution method has been used for rapid assessment of strain growth and stress tolerance. Vector design for genetic inactivation of ODA genes in H. polymorpha was performed using yeast vector pAM773. Selection of "knockout" cell clones was performed using PCR analysis. To complete the transformation process, H. polymorpha was deleted from the pAM773 vector and the obtained DNA was used in the experiment. In vitro cultivation of knockout strains of H. polymorpha was found to exhibit substratespecificity of the ODA. According to the authors, the HP2914 gene is important for D-alanine oxidation, while the gene complex 2400 and 2914 is important for ODA activation in the presence of D-Phe in the medium. It is likely that the gene complex 2082 and 2165 regulates ODA activation when cells are cultured in medium with D-Ala and D-Asp. It was found that in the absence of 2165, 2400, 2914 genes, increased ODA activity to D-Ala only was observed in cell culture medium. The presence of D-alanine combined with 1 % glycerol and 1 % methanol in the culture medium stimulated the activity of the three major ODAs of H. polymorpha through the expression of the HP2914 gene, while the presence of glucose and L-alanine in the culture medium suppressed their activity

Study of Dissolution Kinetics of Mefenamic Acid Solid Dispersion with Polyvinylpyrrolidone

The low solubility of a biologically active substance in an aqueous medium is often the main reason for the reduced therapeutic effect of drugs. The most common approach to solve this problem is to obtain a watersoluble salt of the active substance and an appropriate preparatory formulation based on it. In this case, the solubility of the obtained compound in hydrophobic systems decreases dramatically, which decreases the rate of transmembrane transport and changes the pharmacokinetic laws of the process. In practice, not only the dependence of the therapeutic effect on the salt compound properties, but also a complete loss of the drug active ingredient activity can be observed. The use of biologically active compound solid dispersions in watersoluble polymers is the most promising approach to increase the therapeutic effect of drugs while maintaining the hydrophobic nature of the active component, to reduce the dose load on the patient’s body and obtain prolonged action. In experiments we obtained solid dispersions of mefenamic acid in polyvinylpyrrolidone and studied kinetic regularities of solubility of this promising drug form in aqueous solution of phosphate buffer. By means of mathematical modelling it was found that the phenomenon under study is well described by Ritger --- Peppas model, which considers diffusion of biologically active component into solution according to Fick's law with possible influence on mass transfer at swelling and degradation of polymer matrix

Study of Microwave Radiation Influence on Fuel Oil Desulphurization Process

Many chemical processes are intensified by microwave radiation. The main factor determining the usefulness of microwaves in most transformations of organic compounds is the reaction time reduction to obtain the maximum yield of the target product. The presence of sulphur in oil and petroleum products is detrimental to refining equipment, and also has a negative impact on the environment in the form of waste generated during refining. In this connection development of methods on removal of sulphurcontaining compounds from oil products and oil by their transformation (in particular oxidation) and subsequent removal is very significant. Oxidative desulphurisation of fuel oil takes up to several hours depending on the reagents used. In this work an attempt has been made to significantly reduce the duration of the process. Oxidation of sulphur-containing organic compounds in fuel oil under microwave radiation has been considered, which proceeds in the presence of an oxidizer (hydrogen peroxide) and a catalyst (titanium dioxide). It was found that the oxidative desulphurization of fuel oil at microwave radiation proceeds effectively and quickly within 1--5 min. The achieved degree of desulphurization is 66 % when exposed to microwave radiation for 5 min. The influence of the amount of water in the reaction mixture on the efficiency of oxidative desulphurization of fuel oil under microwave radiation has been studied; it was found that the optimum ratio of water : fuel oil was (1--1.2) : 1

Combined Use of Landsat 8 and Sentinel 2A Images for Enhanced Spatial Resolution of Land Surface Temperature

Underlying surface temperature is an important parameter of underlying surface thermal radiation and can be used in monitoring forest fires, coal fires, urban thermal radiation and developing climate models. Ground-based observations provide temperature information for small areas around weather stations and in fact cannot provide a high density of surface temperature data. Remote sensing technologies are promising in this respect. However, due to the low spatial resolution in the infrared channel, the surface temperature calculated from Landsat and Aster images does not always have the required detail needed when studying small areas. The results of images from Sentinel 2A and Landsat 8 satellites combination (joint digital processing) made in order to increase spatial resolution of underlying surface temperature are presented. Comparison of surface temperature extreme values shows that in spite of small difference in extreme values of temperature, the spatial field of temperature in case of combined images was more detailed and variable. This is evidenced by a significant increase in the variability of the temperature standard deviation. Direct visual observations of image fragments also confirm that combining Sentinel 2A and Landsat 8 images increases the spatial resolution of the surface temperature when compared to the Landsat 8 image

Dry Friction and Mechanical System Motion Implicit Equations

It is shown that forces acting on the mechanical system points could depend on accelerations of the system points. Differential equation system of the mechanical system motion appears to be implicit. It is not resolved with respect to senior derivatives. Fundamental mathematical problems appear associated with possibility and uniqueness of these equations' solution with respect to the senior derivatives. Such problems are common in mechanical systems with dry sliding friction and rolling friction. Such problems are missing in the point dynamics. However, such problems are rather typical in more complex mechanical systems appearing in the study of a rigid body motion, which entire mass is concentrated in a single point, as well as in systems with one degree of freedom. Four fairly simple examples of mechanical systems are considered, and their motion is described by implicit differential motion equations. Situations could appear in these systems, when motion equations are not solvable with respect to the senior derivatives (motion equations are missing), as well as situations, when there are several solutions with respect to senior derivatives (there are several different systems of the mechanical system motion equations). At the same time, one of the fundamental principles of mechanics is not fulfilled, i.e., the principle of determinism

4D Investigation of Vortex Fluid Motion Inside the Eyeball

The eye is a complex system of boundaries and fluids with different viscosities within the boundaries. At present, there are no experimental possibilities to thoroughly observe the dynamic 4D processes after one or another method of eye treatment is applied. The complexity of cumulative, i.e., focusing, and dissipative, i.e., scattering, convective and diffusion 4D fluxes of fluids in the eye requires 4D analytical and numerical models of fluid transfer in the human eyeball to be developed. The purpose of the study was to develop and then verify a numerical model of 4D cumulative-dissipative processes of fluid transfer in the eyeball. The study was the first to numerically evaluate the values of the characteristic time of the drug substance in the vitreous cavity until it is completely washed out, depending on the injection site; to visualize the paths of the vortex motion of the drug in the vitreous cavity; to determine the main parameters of the 4D fluid flows of the medicinal substance in the vitreous cavity, depending on the presence or absence of vitreous detachment from the wall of the posterior chamber of the eye. The results obtained are verified by the experimental data available to doctors. In the eye, as a partially open cumulative-dissipative system, Euler regions with high rates of cumulative flows and regions with low speeds or stagnant Lagrange flow zones are defined