On the self-excitation of vibrations of a boring bar in the process of deep boring

The article presents equivalent mathematical models of a boring bar designed for deep boring, in a distributed and a discrete idealizations. A mathematical model describing coupled torsional and lateral vibrations of a boring bar is constructed in the form of a set of differential equations with lagging of the cutting process dynamics. A methodology for studying stability in small of the deep boring process using a characteristic quasi-polynomial is presented. The numerical-analytical results of the studies made it possible to discern stability regions in the parameter space of the model and to obtain relations for maximal cutting depth as a function of geometrical and technological parameters (stiffness, cutting velocity, feeding etc.) of the boring bar considered. It is noted that the obtained numerical-analytical results are in good agreement with experimental data

A First Principle Approach to Rescale the Dynamics of Simulated Coarse-Grained Macromolecular Liquids

We present a detailed derivation and testing of our approach to rescale the dynamics of mesoscale simulations of coarse-grained polymer melts (I. Y. Lyubimov et al. J. Chem. Phys. \textbf{132}, 11876, 2010). Starting from the first-principle Liouville equation and applying the Mori-Zwanzig projection operator technique, we derive the Generalized Langevin Equations (GLE) for the coarse-grained representations of the liquid. The chosen slow variables in the projection operators define the length scale of coarse graining. Each polymer is represented at two levels of coarse-graining: monomeric as a bead-and-spring model and molecular as a soft-colloid. In the long-time regime where the center-of-mass follows Brownian motion and the internal dynamics is completely relaxed, the two descriptions must be equivalent. By enforcing this formal relation we derive from the GLEs the analytical rescaling factors to be applied to dynamical data in the coarse-grained representation to recover the monomeric description. Change in entropy and change in friction are the two corrections to be accounted for to compensate the effects of coarse-graining on the polymer dynamics. The solution of the memory functions in the coarse-grained representations provides the dynamical rescaling of the friction coefficient. The calculation of the internal degrees of freedom provides the correction of the change in entropy due to coarse-graining. The resulting rescaling formalism is a function of the coarse-grained model and thermodynamic parameters of the system simulated. The rescaled dynamics obtained from mesoscale simulations of polyethylene, represented as soft colloidal particles, by applying our rescaling approach shows a good agreement with data of translational diffusion measured experimentally and from simulations. The proposed method is used to predict self-diffusion coefficients of new polyethylene samples.Comment: 21 pages, 6 figures, 6 tables. Submitted to Phys. Rev.

Математическое моделирование влияния механических свойств аппарата вентиляции на форму отношений поток-объем маневра форсированной жизненной емкости легких выдоха

The mathematical model of mechanics of forced expiration is based on one-component interpretation of the lung but with including their specific mechanical features. Interpretation of lung as a porous body made possible to show the relationships between alveolar and pleural pressures as a dynamic equation, defining changes of lung volume as function of compliant, vicous and relaxation properties of their parenchima. In absence of expiratory stenosis of airways dynamic of Raw is described by law of dependence of its values on deformation airways under maximal Pa. Local resistence of expiratory stenosis was calculated by means of dynamic equation taking into account elastic and viscous properties of the compressed segment of airways. The effort of forced expiration was expressed by individual features of observed man and functions of manoeuver. The model testing showed that by it‘s using influence of phisical ventilation parameters changes on expiratory flow-volume curves could be assessed.Описана математическая модель механики форсированного выдоха, основанная на однокомпонентном представлении легких, но с учетом особенностей физических свойств аппарата вентиляции. Представление легких как упругой пористой среды позволило выразить связь между плевральным и альвеолярным давлениями в виде динамического уравнения, описывающего изменения объема легких с учетом не только упругих, но и вязкостных, а также релаксационных свойств их паренхимы. Для описания динамики аэродинамического сопротивления дыхательных путей в отсутствии экспираторного стеноза и спользованзакон, учитывающий их деформацию в процессе маневра. Местное сопротивление экспираторного стеноза рассчитано по динамическому уравнению с учетом вязко-упругих свойств стенки дыхательных путей в месте сужения. Усилие дыхательных путей, обеспечивающее форсированный выдох, выражено через индивидуальные характеристики испытуемого и функции маневра, определяющие характер его выполнения. Проведенное тестирование модели показало, что с ее помощью можно оценить влияние изменений отдельных параметров аппарата вентиляции на форму отношения поток – объем маневра ФЖЕЛ

Neutral Particles in Light of the Majorana-Ahluwalia Ideas

The first part of this article (Sections I and II) presents oneself an overview of theory and phenomenology of truly neutral particles based on the papers of Majorana, Racah, Furry, McLennan and Case. The recent development of the construct, undertaken by Ahluwalia [{\it Mod. Phys. Lett. A}{\bf 9} (1994) 439; {\it Acta Phys. Polon. B}{\bf 25} (1994) 1267; Preprints LANL LA-UR-94-1252, LA-UR-94-3118], could be relevant for explanation of the present experimental situation in neutrino physics and astrophysics. In Section III the new fundamental wave equations for self/anti-self conjugate type-II spinors, proposed by Ahluwalia, are re-casted to covariant form. The connection with the Foldy-Nigam-Bargmann-Wightman- Wigner (FNBWW) type quantum field theory is found. The possible applications to the problem of neutrino oscillations are discussed.Comment: REVTEX file. 21pp. No figure

Effect of short PSG peptide fragments on the cytokine profile in Wistar rats during allogeneic transplantation <i>in vivo</i>

Pregnancy-specific beta-1-glycoprotein (PSG) is a protein with pleiotropic biological effects, particularly immunoregulatory and immunosuppressive potential. The use of recombinant PSG may exert therapeutic effects in experimental animals with induced autoimmune diseases. Recently, a search for the biological effects of short linear motifs (SLiMs) has become a new strategy for designing the pharmacological compounds. Tetrapeptide regions have been identified in the primary structure of several PSGs: YQCE, YECE and YACS, these SLiMs exhibit immunomodulatory activity. The aim of our study was to evaluate the prospectives for usage of PSG peptide fragments as pharmacological agents to modulate transplant immunity. We used an original model of host-versus-graft response in male Wistar rats transplanted with bone marrow, without prior conditioning treatment of recipients. We used a cocktail of the PSG peptide fragments administered to Wistar rats in the course of allogeneic bone marrow transplantation (BM) in dynamic manner, evaluating the cytokine profile as an integral index of immune response. Cytokine levels were determined by multiplex method using Bio-Plex ProTM Rat 23-Plex kit. Statistical processing of the data was performed by means of two-way analysis of variance and Tukey’s post hoc test for multiple comparisons. We have found that the levels of pro-inflammatory cytokines (IFNγ, IL-1α, IL-1β, IL-18), as well as the contents of G-CSF, GM-CSF and IL-7 were increased in the animals injected with BM only. In the group of animals injected with BM + PSG peptides, an increase in IFNγ, IL-6, TNFα was observed, which decreased by the end of the experiment. Increased levels of antiinflammatory cytokines IL-4 and IL-13 were detected in blood serum of the animals on day +14. Moreover, administration of PSG peptides also led to increase in IL-2, M-CSF, MCP-1, and RANTES levels on day 14 from the beginning of the experiment, and to a gradual decrease in their levels till the end of the experiment. Meanwhile, control group showed a marked tendency for increase of these and other cytokines. Thus, it was shown that the use of PSG peptides upon development of immune response to BM allograft may promote a return to normal levels for the most cytokines studied, thus presuming the immunopharmacological potential of these peptides. The obtained data can be used to develop a pharmacological preparation of the studied peptides to correct the imbalance of immune system

Dark matter and structure formation a review

This paper provides a review of the variants of dark matter which are thought to be fundamental components of the universe and their role in origin and evolution of structures and some new original results concerning improvements to the spherical collapse model. In particular, I show how the spherical collapse model is modified when we take into account dynamical friction and tidal torques

An insight into imbalanced Big Data classification: outcomes and challenges

Big Data applications are emerging during the last years, and researchers from many disciplines are aware of the high advantages related to the knowledge extraction from this type of problem. However, traditional learning approaches cannot be directly applied due to scalability issues. To overcome this issue, the MapReduce framework has arisen as a “de facto” solution. Basically, it carries out a “divide-and-conquer” distributed procedure in a fault-tolerant way to adapt for commodity hardware. Being still a recent discipline, few research has been conducted on imbalanced classification for Big Data. The reasons behind this are mainly the difficulties in adapting standard techniques to the MapReduce programming style. Additionally, inner problems of imbalanced data, namely lack of data and small disjuncts, are accentuated during the data partitioning to fit the MapReduce programming style. This paper is designed under three main pillars. First, to present the first outcomes for imbalanced classification in Big Data problems, introducing the current research state of this area. Second, to analyze the behavior of standard pre-processing techniques in this particular framework. Finally, taking into account the experimental results obtained throughout this work, we will carry out a discussion on the challenges and future directions for the topic.This work has been partially supported by the Spanish Ministry of Science and Technology under Projects TIN2014-57251-P and TIN2015-68454-R, the Andalusian Research Plan P11-TIC-7765, the Foundation BBVA Project 75/2016 BigDaPTOOLS, and the National Science Foundation (NSF) Grant IIS-1447795