Электрооборудование и электропривод механизма напора экскаватора ЭКГ-15

В работе произведён расчёт и выбор силового оборудования для электропривода механизма напора карьерного экскаватора.Произведен расчет силовой части электропривода. Рассчитаны и построены характеристики электропривода, построены переходные процессы.In operation, calculation and selection of power equipment for electric drive of pressure mechanism of mine excavator was performed. Electric drive power part was calculated. The characteristics of the electric drive have been calculated and built, and transitional processes have been built

Progenitor cells of the testosterone-producing Leydig cells revealed

The cells responsible for production of the male sex hormone testosterone, the Leydig cells of the testis, are post-mitotic cells with neuroendocrine characteristics. Their origin during ontogeny and regeneration processes is still a matter of debate. Here, we show that cells of testicular blood vessels, namely vascular smooth muscle cells and pericytes, are the progenitors of Leydig cells. Resembling stem cells of the nervous system, the Leydig cell progenitors are characterized by the expression of nestin. Using an in vivo model to induce and monitor the synchronized generation of a completely new Leydig cell population in adult rats, we demonstrate specific proliferation of vascular progenitors and their subsequent transdifferentiation into steroidogenic Leydig cells which, in addition, rapidly acquire neuronal and glial properties. These findings, shown to be representative also for ontogenetic Leydig cell formation and for the human testis, provide further evidence that cellular components of blood vessels can act as progenitor cells for organogenesis and repair

Critical Behaviour of Non-Equilibrium Phase Transitions to Magnetically Ordered States

We describe non-equilibrium phase transitions in arrays of dynamical systems with cubic nonlinearity driven by multiplicative Gaussian white noise. Depending on the sign of the spatial coupling we observe transitions to ferromagnetic or antiferromagnetic ordered states. We discuss the phase diagram, the order of the transitions, and the critical behaviour. For global coupling we show analytically that the critical exponent of the magnetization exhibits a transition from the value 1/2 to a non-universal behaviour depending on the ratio of noise strength to the magnitude of the spatial coupling.Comment: 4 pages, 5 figure

Anomalous stress relaxation in random macromolecular networks

Within the framework of a simple Rouse-type model we present exact analytical results for dynamical critical behaviour on the sol side of the gelation transition. The stress-relaxation function is shown to exhibit a stretched-exponential long-time decay. The divergence of the static shear viscosity is governed by the critical exponent $k=\phi -\beta$, where $\phi$ is the (first) crossover exponent of random resistor networks, and $\beta$ is the critical exponent for the gel fraction. We also derive new results on the behaviour of normal stress coefficients.Comment: 13 pages, 6 figures; contribution to the proceedings of the Minerva International Workshop on Frontiers In The Physics Of Complex Systems (25-28 March 2001) - to appear in a special issue of Physica

Анализ средств измерений количества и показателей качества нефти на примере приемно-сдаточного пункта Томской области

Объектом исследования является: система измерений количества и показателей качества нефти на примере приемо-сдаточного пункта Томской области. Цель работы: провести анализ средств измерений, участвующих в товаро-коммерческих операциях, а также рассмотреть основное оборудование по автоматическому контролю за качественными и количественными характеристиками на ПСП Томской области. В процессе работы проводился: Анализ средств измерений количества и показателей качества нефти на примере приемо-сдаточного пункта Томской области. Произведен расчет погрешностей измерений при прямом методе динамических измерений массы нефти.The object of study is: a system for measuring the quantity and quality indicators of oil on the example of an acceptance point of the Tomsk region. Purpose of work: to analyze the measuring instruments involved in commodity-commercial operations, as well as to consider the basic equipment for automatic control of qualitative and quantitative characteristics at the border crossing point of the Tomsk region. In the process of work was carried out: Analysis of measuring instruments for the quantity and quality indicators of oil on the example of the acceptance point of the Tomsk region. The measurement errors were calculated with the direct method of dynamic measurements of oil mass

Hepcidin Is an Antibacterial, Stress-Inducible Peptide of the Biliary System

BACKGROUND/AIMS: Hepcidin (gene name HAMP), an IL-6-inducible acute phase peptide with antimicrobial properties, is the key negative regulator of iron metabolism. Liver is the primary source of HAMP synthesis, but it is also produced by other tissues such as kidney or heart and is found in body fluids such as urine or cerebrospinal fluid. While the role of hepcidin in biliary system is unknown, a recent study demonstrated that conditional gp130-knockout mice display diminished hepcidin levels and increased rate of biliary infections. METHODS: Expression and localization of HAMP in biliary system was analyzed by real time RT-PCR, in-situ hybridization, immunostaining and -blotting, while prohepcidin levels in human bile were determined by ELISA. RESULTS: Hepcidin was detected in mouse/human gallbladder and bile duct epithelia. Biliary HAMP is stress-inducible, in that it is increased in biliary cell lines upon IL-6 stimulation and in gallbladder mucosa of patients with acute cholecystitis. Hepcidin is also present in the bile and elevated prohepcidin levels were observed in bile of primary sclerosing cholangitis (PSC) patients with concurrent bacterial cholangitis compared to PSC subjects without bacterial infection (median values 22.3 vs. 8.9; p = 0.03). In PSC-cholangitis subjects, bile prohepcidin levels positively correlated with C-reactive protein and bilirubin levels (r = 0.48 and r = 0.71, respectively). In vitro, hepcidin enhanced the antimicrobial capacity of human bile (p<0.05). CONCLUSION: Hepcidin is a stress-inducible peptide of the biliary epithelia and a potential marker of biliary stress. In the bile, hepcidin may serve local functions such as protection from bacterial infections

Critical behaviour of the Rouse model for gelling polymers

It is shown that the traditionally accepted "Rouse values" for the critical exponents at the gelation transition do not arise from the Rouse model for gelling polymers. The true critical behaviour of the Rouse model for gelling polymers is obtained from spectral properties of the connectivity matrix of the fractal clusters that are formed by the molecules. The required spectral properties are related to the return probability of a "blind ant"-random walk on the critical percolating cluster. The resulting scaling relations express the critical exponents of the shear-stress-relaxation function, and hence those of the shear viscosity and of the first normal stress coefficient, in terms of the spectral dimension $d_{s}$ of the critical percolating cluster and the exponents $\sigma$ and $\tau$ of the cluster-size distribution.Comment: 9 pages, slightly extended version, to appear in J. Phys.

Die Untersuchung der paläolithischen Freilandstation von Salzgitter-Lebenstedt

researc