329 research outputs found
Self-Field Effects in Magneto-Thermal Instabilities for Nb-Sn Strands
Recent advancements in the critical current density (Jc) of NbSn conductors, coupled with a large effective filament size, have drawn attention to the problem of magnetothermal instabilities. At low magnetic fields, the quench current of such high Jc NbSn strands is significantly lower than their critical current because of the above-mentioned instabilities. An adiabatic model to calculate the minimum current at which a strand can quench due to magneto-thermal instabilities is developed. The model is based on an 'integral' approach already used elsewhere [1]. The main difference with respect to the previous model is the addition of the self-field effect that allows to describe premature quenches of non-magnetized NbSn strands and to better calculate the quench current of strongly magnetized strands. The model is in good agreement with experimental results at 4.2 K obtained at Fermilab using virgin Modified Jelly Roll (MJR) strands with a low Residual Resistivity Ratio (RRR) of the stabilizing copper. The prediction of the model at 1.9 K and the results of the tests carried out at CERN, at 4.2 K and 1.9 K, on a 0.8 mm Rod Re-Stack Process (RRP) strand with a low RRR value are discussed. At 1.9 K the test revealed an unexpected strand performance at low fields that might be a sign of a new stability regime
Special Values of Generalized Polylogarithms
We study values of generalized polylogarithms at various points and
relationships among them. Polylogarithms of small weight at the points 1/2 and
-1 are completely investigated. We formulate a conjecture about the structure
of the linear space generated by values of generalized polylogarithms.Comment: 32 page
Integrals Over Polytopes, Multiple Zeta Values and Polylogarithms, and Euler's Constant
Let be the triangle with vertices (1,0), (0,1), (1,1). We study certain
integrals over , one of which was computed by Euler. We give expressions for
them both as a linear combination of multiple zeta values, and as a polynomial
in single zeta values. We obtain asymptotic expansions of the integrals, and of
sums of certain multiple zeta values with constant weight. We also give related
expressions for Euler's constant. In the final section, we evaluate more
general integrals -- one is a Chen (Drinfeld-Kontsevich) iterated integral --
over some polytopes that are higher-dimensional analogs of . This leads to a
relation between certain multiple polylogarithm values and multiple zeta
values.Comment: 19 pages, to appear in Mat Zametki. Ver 2.: Added Remark 3 on a Chen
(Drinfeld-Kontsevich) iterated integral; simplified Proposition 2; gave
reference for (19); corrected [16]; fixed typ
Development of the Multi-Analyte Test for Immune-Chromatographic Detection of Botulinum Toxins
Designed is the multi-analyte test for simultaneous immune chromatographic detection of A & B type botulinum neurotoxins (BT), using colloid gold nanoparticles. It is meant for food and environmental samples' analysis. The sensitivity of simultaneous BT detection of the A (30 ng/ml) and B (10 ng/ml) types is as high as that of mono-analytical tests, designed for one type BT detection. The test is demonstrated to be a specific one and can be used for BT detection in food stuffs
Construction of Immune-Chromatographic Indicator Elements for Burnet Rickettsia Detection
mc/ml, and the elapsed time – 20 minutes. The IE is specific to other members of the family Ricketsiaceae, for instance to R. prowazekii , to antigen complexes of R. prowazekii and R. sibirika , as well as to vaccinia virus (L-IVP strain). The IE engineered can be used for rapid indication of Burnet Rickettsia at different stages of laboratory investigation. Span time reduction, lack of necessity to perform any accessory technological operations, visual and (or) automatic registration of the results build up premises to observe immune-chromatographic method for Burnet Rickettsia detection as one of the alternatives for identification of these microorganisms under field conditions when monitoring ambient environment objects
Multiple (inverse) binomial sums of arbitrary weight and depth and the all-order epsilon-expansion of generalized hypergeometric functions with one half-integer value of parameter
We continue the study of the construction of analytical coefficients of the
epsilon-expansion of hypergeometric functions and their connection with Feynman
diagrams. In this paper, we show the following results:
Theorem A: The multiple (inverse) binomial sums of arbitrary weight and depth
(see Eq. (1.1)) are expressible in terms of Remiddi-Vermaseren functions.
Theorem B: The epsilon expansion of a hypergeometric function with one
half-integer value of parameter (see Eq. (1.2)) is expressible in terms of the
harmonic polylogarithms of Remiddi and Vermaseren with coefficients that are
ratios of polynomials. Some extra materials are available via the www at this
http://theor.jinr.ru/~kalmykov/hypergeom/hyper.htmlComment: 24 pages, latex with amsmath and JHEP3.cls; v2: some typos corrected
and a few references added; v3: few references added
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