Analitic Investigation of the Regularities of Changing Dust Concentration During the Abrasive Decrease of Stone Structures

In the process of repair or restoration of building structures, it is often necessary to strengthen building structures from limestone-shell rock, concrete, reinforced concrete, hard materials-granite, basalt, etc. by cutting or making cuts of the required size with detachable circles of synthetic diamond and cubic boron nitride (CA and CBN)The cutting process is accompanied by considerable dust formation, which can be both harmful and dangerous factor in the work.The aim of the work is studying the process of dust sedimentation and the regularity of the change in dust concentration during the abrasive cutting of concrete and stone materials.Mathematical models have been developed – dust emission from under the wheel, speed of sedimentation of dust particles depending on their material, size and shape, and also depending on temperature, pressure and humidity, the concentration of dust in the working space and the concentration change during the cutting cycle are calculated.It is shown that the velocity of the sedimentation of particles depends significantly on the shape. The higher the sphericity, the higher the sedimentation rate. The ambient temperature has little effect on the sedimentation rate, in the temperature range (-20 → + 40 °C) at which the operation takes place.The sedimentation rate of dust particles generated by cutting the most common building stone materials also differs slightly. Almost the same sedimentation rate has dust particles obtained by cutting basalt and concrete. A bit higher is the sedimentation rate of particles from granite.The sedimentation rate of particles of generated dust is about 600-700 cm/h or 10-11 cm/min for particles measuring 6 μm. This means that at a production height of about 2 m (200 cm) during the operating cycle (about 3 min), the dust will remain at an altitude of about 1.5 m, i.е. practically remains in the working area. This gives grounds to assert about a high concentration of dust during the cutting cycle (about 4.8 108/m3)

Simulation of Beam-Beam Effects and Tevatron Experience

Effects of electromagnetic interactions of colliding bunches in the Tevatron had a variety of manifestations in beam dynamics presenting vast opportunities for development of simulation models and tools. In this paper the computer code for simulation of weak-strong beam-beam effects in hadron colliders is described. We report the collider operational experience relevant to beam-beam interactions, explain major effects limiting the collider performance and compare results of observations and measurements with simulations.Comment: 23 pages, 17 figure

The gas phase cyclization of deprotonated N-aryl-2-cyano-2-diazoacetamides

The document attached has been archived with permission from the publisher.1-Aryl-4-cyano-5-hydroxy-1,2,3-triazoles can be obtained in solution by base-catalysed cyclization of N-aryl-2-cyano-2-diazoacetamides. A similar reaction was shown to take place under conditions of negative ion chemical ionization in the ion source of a mass spectrometer. High resolution mass spectrometry, tandem mass spectrometry, charge reversal spectra, synthesis of the ions with known structures and quantum chemical calculations were used to prove the latter statement. The fact of the observed cyclization demonstrates once again the ability of mass spectrometry to study the gas phase chemical reactions that take place in solution.Vladislav V. Lobodin, Yuriy Yu. Morzherin, Tom Blumenthal, Daniel Bilusich, Vladimir V. Ovcharenko, John H. Bowie, and Albert T. Lebede

Feasibility study of the grinding process of grain materials

For a comparative assessment of the effectiveness of various types of grinders of grain materials, various approaches are used. As the main criterion, the correspondence of the crushed material according to the particle size distribution can be taken as an indicator of the reliability of the grinding process. A comparative assessment of rotary crushers is carried out using the technical and economic indicator Eg, which is the ratio of total costs to the implementation of a given amount of work. Under the reliability of the grinding process, we have accepted the condition that the particle size distribution will comply with the requirements for agricultural feeding animals, which is possible while maintaining a rational gap between the stator and rotor riffles. The contradiction manufacturing techniques for the experiment are divided into: option No. 1 – steel 3 (HRC 10–12), option No. 2 – steel 45 (HRC 15–17), option No. 3 – hardened steel 45 (HRC 45–50), option No. 4 – steel 45 hardened and having a thin-film coating of FPH (finish plasma hardening), microhardness of 13 GPa. If reliability of the grinding process equal to 80%, wear on the fourth option, the cost was 1,171 rubles per ton, which is 16% lower than the cost of the first version of the production of a rotor crusher equal to 1,405 rubles per ton, respectively, this all speaks of the possible use of the proposed options for various forms of ownership of agricultural enterprises

Magnetization and susceptibility of ferrofluids

A second-order Taylor series expansion of the free energy functional provides analytical expressions for the magnetic field dependence of the free energy and of the magnetization of ferrofluids, here modelled by dipolar Yukawa interaction potentials. The corresponding hard core dipolar Yukawa reference fluid is studied within the framework of the mean spherical approximation. Our findings for the magnetic and phase equilibrium properties are in quantitative agreement with previously published and new Monte Carlo simulation data.Comment: 8 pages including 4 figure

Age-dependent role of steroids in the regulation of growth of the hen follicular wall

<p>Abstract</p> <p>Background</p> <p>The ovaries are the primary targets of senescence effects in mammalian and avian species. In the present study, relationships between reproductive aging, sex steroids and the growth pattern of the pre-ovulatory follicle wall were investigated using young hens with long clutch (YLC), old hens with long clutch (OLC), old hens with short clutch (OSC), and old hens with interrupted long clutch (OILC).</p> <p>Methods</p> <p>Experiment 1: Hens were sacrificed 1.5 and 14.5 h after ovulation. Experiment 2: YLC and OILC hens were sacrificed 3.5 h after treatments with LH and/or aminoglutethimide (AG), an inhibitor of steroid synthesis. Volumes of pre-ovulatory follicles (F1-F5) and plasma concentrations of ovarian steroids were determined. Experiment 3: Granulosa and theca cells from F3 follicles of OSC and/or YLC hens were exposed in vitro to estradiol-17beta (E₂), testosterone (T) and LH and the proliferative activity of the cells was examined using CellTiter 96 Aqueous One Solution Assay.</p> <p>Results</p> <p>In YLC and OLC groups, the total volume of F1-F5 follicles rose between 1.5 and 14.5 h after ovulation (P < 0.01), negatively correlating with the plasma level of E₂(P < 0.01). There was no growth of pre-ovulatory follicles in the middle of the ovulatory cycle in the OSC group, with a positive correlation being present between E₂and the follicular volume (P < 0.05). In young hens, AG caused a rise in the total follicular volume. This rise was associated with a fall in E₂(r = -0.54, P < 0.05). E₂enhanced proliferation of granulosa cells from YLC and OSC groups. The proliferative activity of granulosa and theca cells of YLC hens depended on the interaction between T and LH (P < 0.01).</p> <p>Conclusions</p> <p>These data indicate for the first time that the growth pattern of pre-ovulatory follicles during the ovulatory cycle changes in the course of reproductive aging. E₂seems to play a dual role in this adjustment; it stimulates the growth of the follicular wall in reproductive aged hens, whereas it may inhibit this process in young birds. T and LH are apparently involved in the growth regulation during the pre-ovulatory surge in young hens.</p

Astrophysical jets: observations, numerical simulations, and laboratory experiments

This paper provides summaries of ten talks on astrophysical jets given at the HEDP/HEDLA-08 International Conference in St. Louis. The talks are topically divided into the areas of observation, numerical modeling, and laboratory experiment. One essential feature of jets, namely, their filamentary (i.e., collimated) nature, can be reproduced in both numerical models and laboratory experiments. Another essential feature of jets, their scalability, is evident from the large number of astrophysical situations where jets occur. This scalability is the reason why laboratory experiments simulating jets are possible and why the same theoretical models can be used for both observed astrophysical jets and laboratory simulations

Correcting for Distortions due to Ionization in the STAR TPC

Physics goals of the STAR Experiment at RHIC in recent (and future) years drive the need to operate the STAR TPC at ever higher luminosities, leading to increased ionization levels in the TPC gas. The resulting ionic space charge introduces field distortions in the detector which impact tracking performance. Further complications arise from ionic charge leakage into the main TPC volume from the high gain anode region. STAR has implemented corrections for these distortions based on measures of luminosity, which we present here. Additionally, we highlight a novel approach to applying the corrections on an event-by-event basis applicable in conditions of rapidly varying ionization sources.Comment: 6 pages, 7 figures, proceedings of the Workshop on Tracking in High Multiplicity Environments (TIME 05) in Zurich, Switzerland, submitted to Nucl. Instr. and Meth.

Invisible Higgs and Scalar Dark Matter

In this proceeding, we show that when we combined WMAP and the most recent results of XENON100, the invisible width of the Higgs to scalar dark matter is negligible(<10%), except in a small region with very light dark matter (< 10 GeV) not yet excluded by XENON100 or around 60 GeV where the ratio can reach 50% to 60%. The new results released by the Higgs searches of ATLAS and CMS set very strong limits on the elastic scattering cross section.Comment: 4 pages, 2 figures, proceeding TAUP2011 References adde

Dynamics of DNA-breathing: Weak noise analysis, finite time singularity, and mapping onto the quantum Coulomb problem

We study the dynamics of denaturation bubbles in double-stranded DNA on the basis of the Poland-Scheraga model. We show that long time distributions for the survival of DNA bubbles and the size autocorrelation function can be derived from an asymptotic weak noise approach. In particular, below the melting temperature the bubble closure corresponds to a noisy finite time singularity. We demonstrate that the associated Fokker-Planck equation is equivalent to a quantum Coulomb problem. Below the melting temperature the bubble lifetime is associated with the continuum of scattering states of the repulsive Coulomb potential; at the melting temperature the Coulomb potential vanishes and the underlying first exit dynamics exhibits a long time power law tail; above the melting temperature, corresponding to an attractive Coulomb potential, the long time dynamics is controlled by the lowest bound state. Correlations and finite size effects are discussed.Comment: 12 pages, 10 figures, revte