Generalized gap function in the dynamic interaction problems of elements of vibrational technological machines with “not holding” ties

Issues of formation of rational modes of dynamic interaction of contacting elements of vibrating machines in problems of increase in quality of technological vibrohardening processes are considered. Mathematical models and criteria of an estimation of forms of movement with “not holding” ties are developed. For analytical research of “not holding” ties the concept of the generalized gap function is entered. The model of dynamic interaction of a solid with a vibrating surface is developed at introduction of additional external forces and elastic interactions. On the basis of a method of gap function criteria of a separation are formulated and forms of movement of a material particle in dynamic interaction with a vibrating surface are proved. The generalized approach for problems of dynamic synthesis of the vibrating technologies realized in modes continuous tossing is offered. Conditions of realization of multiple modes continuous tossing when the period of free flight of a material particle makes an integer of the periods of a basic vibrating surface are formulated. Generalization of considered models on a compound solid, interaction between which elements has “not holding” character is offered. The problem of definition of gapless conditions of movements at vibrating influence on a compound solid by a surface is posed. Conditions of formation of reaction in the oscillatory system formed by several solid elements with “not holding” ties, connected among themselves by means of elastic interaction and power factors are defined. In respect of practical appendices, the problem of development and experimental approbation of the measuring devices fixing modes of continuous tossing is posed

Somatotypes and hand-grip strength analysis of elite cadet sambo athletes

The objectives of this research were to establish somatotype and hand-grip strength between elite cadet male and female sambo athletes divided by weight categories. A total of 97 elite cadet sambo athletes, participants of the World Cadets Sambo Championships 2018 participated in the study. Male and female sambo athletes were divided by official weight categories. Anthropometrical variables were taken in order to calculate somatotypes and hand-grip strength. A one-way analysis of variance and Tukey's post hoc tests were used to compare group differences by weight categories. Results of this study provide the first description of somatotype and hand-grip strength of elite male and female cadet sambo athletes in relation to weight category. A typical somatotype in male sambo athletes was endomorphic mesomorphs with a predominance of musculoskeletal tissue, while female athletes differed concerning weight category. Overall, an increase in handgrip strength across weight categories was noted. Hand-grip strength increases linearly from the lightest to the heaviest weight category except in -66 and -84 kg in male athletes. Differences in handgrip strength of female athletes were detected between the lightest group and last six groups in all three variables in favor of last six as well as -44 and kg -48 kg compared with the heaviest. To the best of our knowledge, this study provides the first normative data of somatotype and hand-grip strength analyses in relation to age, gender, and weight categories of cadet sambo athletes. The anthropometric profile of sambo athletes changed according to their weight category. Mesomorphy was the most dominant somatotype component in male athletes, while female had three different types of somatotype component in relation to weight category. In conclusion, we found differences in hand-grip strength related to weight category, which can be linked to the muscle mass of athletes. Future studies should focus on somatotype and strength handgrip values of international compared to national level sambo athletes

Localization of vibration effects: the possibilities of dynamic damping of vibrations

. The possibilities of changing the dynamic state of mechanical oscillatory systems are considered on the basis of using additional connections that are implemented by introducing lever mechanisms. Through the example of the problem of the dynamics of a solid body with two degrees of freedom and elastic supports, it is shown that the kinematic impact on the side of the bearing surface can be greatly reduced by a deliberate displacement of the concentrated masses on the elements of the lever device. The method for developing mathematical models is proposed. The results of the experiment are presented

The optimization method of the integrated management system security audit

Nowadays the application of integrated management systems (IMS) attracts the attention of top management from various organizations. However, there is an important problem of running the security audits in IMS and realization of complex checks of different ISO standards in full scale with the essential reducing of available resources

Diffusion doping route to plasmonic Si/SiOx nanoparticles

International audienceSemiconductor nanoparticles (SNPs) are a valuable building block for functional materials. Capabilities for engineering of electronic structure of SNPs can be further improved with development of techniques of doping by diffusion, as post-synthetic introduction of impurities does not affect the nucleation and growth of SNPs. Diffusion of dopants from an external source also potentially allows for temporal control of radial distribution of impurities. In this paper we report on the doping of Si/SiOx SNPs by annealing particles in gaseous phosphorus. The technique can provide efficient incorporation of impurities, controllable with precursor vapor pressure. HRTEM and X-ray diffraction studies confirmed that obtained particles retain their nanocrystallinity. Elemental analysis revealed doping levels up to 10%. Electrical activity of the impurity was confirmed through thermopower measurements and observation of localized surface plasmon resonance in IR spectra. The plasmonic behavior of etched particles and EDX elemental mapping suggest uniform distribution of phosphorus in the crystalline silicon cores. Impurity activation efficiencies up to 34% were achieved, which indicate high electrical activity of thermodynamically soluble phosphorus in oxide-terminated nanosilicon

Potassium Ions are More Effective than Sodium Ions in Salt Induced Peptide Formation

Prebiotic peptide formation under aqueous conditions in the presence of metal ions is one of the plausible triggers of the emergence of life. The salt-induced peptide formation reaction has been suggested as being prebiotically relevant and was examined for the formation of peptides in NaCl solutions. In previous work we have argued that the first protocell could have emerged in KCl solution. Using HPLC-MS/MS analysis, we found that K(+) is more than an order of magnitude more effective in the L-glutamic acid oligomerization with 1,1'-carbonyldiimidazole in aqueous solutions than the same concentration of Na(+), which is consistent with the diffusion theory calculations. We anticipate that prebiotic peptides could have formed with K(+) as the driving force, not Na(+), as commonly believed

Observation of a low-lying metastable electronic state in highly charged lead by Penning-trap mass spectrometry

Highly charged ions (HCIs) offer many opportunities for next-generation clock research due to the vast landscape of available electronic transitions in different charge states. The development of XUV frequency combs has enabled the search for clock transitions based on shorter wavelengths in HCIs. However, without initial knowledge of the energy of the clock states, these narrow transitions are difficult to be probed by lasers. In this Letter, we provide experimental observation and theoretical calculation of a long-lived electronic state in Nb-like Pb$^{41+}$ which could be used as a clock state. With the mass spectrometer Pentatrap, the excitation energy of this metastable state is directly determined as a mass difference at an energy of 31.2(8) eV, corresponding to one of the most precise relative mass determinations to date with a fractional uncertainty of $4\times10^{-12}$. This experimental result agrees within 1 $\sigma$ with two partially different \textit{ab initio} multi-configuration Dirac-Hartree-Fock calculations of 31.68(13) eV and 31.76(35) eV, respectively. With a calculated lifetime of 26.5(5.3) days, the transition from this metastable state to the ground state bears a quality factor of $1.1\times10^{23}$ and allows for the construction of a HCI clock with a fractional frequency instability of $<10^{-19}/\sqrt{\tau}$

The decay energy of the pure s-process nuclide ¹²³ Te

A direct and high-precision measurement of the mass difference of ¹²³Te and ¹²³Sb has been performed with the Penning-trap mass spectrometer SHIPTRAP using the recently introduced phase-imaging ioncyclotron-resonance technique. The obtained mass difference is 51.912(67) keV/c². Using the masses of the neutral ground states and the energy difference between the ionic states an effective half-life of ¹²³Te has been estimated for various astrophysical conditions. A dramatic influence of the electron capture process on the decay properties of ¹²³Te in hot stellar conditions has been discussed