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Abstract  

The paper gives a survey of the history of damping methods for balances. Representation on Egyptian drawings demonstrate that the person performing the weighing shortened the measuring time by holding the suspension cords and touching the beam. By means of delimiters, the Romans constricted the deflection amplitudes. In the 19th century, the movements of precision balances were damped with a brush. For analytical balances, locking mechanism were developed, often combined with levers lifting the weighing scales and the beam in order to relieve the knife-edges. Half-arresting was used to curtail weighings. Air damping was invented by Arzberger in 1875, and eddy current damping by Marek in 1906. In electronic balances, lag, lead and filter elements and absorptive attenuators are used. For digital balances, the fast-reacting nullification of eddy signals is applied.

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Scarpa F., Landi F. P., Rongong J. A., DeWitt L., Tomlinson G. Improving the MSE method for viscoelastic damped structures, Smart Structures and Materials Proceedings of SPIE Vol. 4697, 2002, pp. 25

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importance to increase the efficiency and to develop an effective and accurate control depending on the area of application. One particular analogy is the nonlinear behavior of Magneto-Rheological (MR) dampers, in particular its damping properties. From the

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Amer. J. Math. 70 395 399 HATVANI, L., Integral conditions on the asymptotic stability for the damped

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Kurucheve, V. and Padmavathi, R. (1998): Management of damping off of chillies with plant products. Indian Phytopathol. 51, 379–381. Padmavathi R. Management of damping off of chillies

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Summary  

Using the integral average method, we give some new oscillation criteria for the second order differential equation with damped term  (a(t)Ψ(x(t))K(x'(t)))'+p(t)K(x'(t))+q(t)f(x(t))=0, t≧t0. These results improve and generalize the oscillation criteria in[1], because they eliminate both the differentiability of p(t) and the sign of p(t), q(t). As a consequence, improvements of Sobol's type oscillation criteria are obtained.

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Abstract  

This paper is concerned with a class of even order nonlinear damped differential equations

\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage{bbm} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\begin{gathered} {\text{ }}x^{(n)} (t) + p(t)x^{(n - 1)} (t) \hfill \\ + f\left( {t,x[\tau _{01} (t)],...,x[\tau _{0m} (t)],...,x^{(n - 1)} [\tau _{n - 11} (t)],...,x^{{\text{(n - 1)}}} [\tau _{n - 1n} (t)]} \right) = 0 \hfill \\ \end{gathered}$$ \end{document}
where n is even and tt 0. By using the generalized Riccati transformation and the averaging technique, new oscillation criteria are obtained which are either extensions of or complementary to a number of existing results.

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Abstract  

We present some criteria for the oscillation of the second order nonlinear differential equation [a(t)ψ(x(t))x'(t)]' + p(t)x'(t) + q(t)f (x(t)) =0, tt 0> 0 with damping where aC 1 ([t 0,∞)) is a nonnegative function, p, q∈ C([t 0,∞)) are allowed to change sign on [t 0,∞), ψ, f∈C(R) with ψ(x) ≠ 0, xf(x)/ψ(x) > 0 for x≠ 0, and ψ, f have continuous derivatives on R{0} with [f(x) / ψ(x)]' ≧ 0 for x≠ 0. This criteria are obtained by using a general class of the parameter functions H(t,s) in the averaging techniques. An essential feature of the proved results is that the assumption of positivity of the function ψ(x) is not required. Consequently, the obtained criteria cover new classes of equations to which known results do not apply.

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Abstract  

A gas jet system has been developed at the Darmstadt UNILAC for the investigation of products from damped reactions in U targets induced by U, Pb, or Xe. The design of that system accounts especially for the considerable energy loss of very heavy ions in matter and for the extended spatial distributions of damped reaction products stopped in the gas. Production cross sections for -active nuclides have been measured in the reaction U+U with an aerosol-loaded argon jet.

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Metastable effects on martensitic transformation in SMA

Part VIII. Temperature effects on cycling

Journal of Thermal Analysis and Calorimetry
Authors: V. Torra, C. Auguet, A. Isalgue, F. Lovey, A. Sepulveda, and H. Soul

Abstract  

The use of Shape Memory Alloys (SMA) in technical applications as damping in civil engineering structures requires the characterization of the alloy for each specific application. This involves the evolution of the mechanical properties and damping capacity with the number of cycles, frequency, maximum deformation, applied stresses, and the evolution of the alloy with aging time and temperature. In particular, the temperature effects associated to self-heating need to be evaluated. In continuous cycling the effects of latent heat, the associated dissipation induced by the hysteresis, the heat flow to surroundings and the cycling frequency induce different states of temperature in the specimen, which in turn produces changes in the transformation-retransformation stresses. In this article, the temperature effects associated to cycling are outlined for different cycling frequencies. The results show that, for relatively faster frequency the temperature arrives at an oscillatory state superimposed to an exponential increase. For lower frequencies, some parts of the sample attain temperatures below room temperature. The experimental results are represented with an elementary model (the 1-body model or the Tian equation used in calorimetric representation) of heat transfer. For the higher fracture where life requirements are associated to damping in stayed cables for bridges, the results show (for the NiTi alloy) a reduction of the hysteresis width as the frequency increases for deformations up to 8%. For reduced deformation, under 2% appears an asymptotic behavior where the frictional area is practically independent of the cycling frequency (up to 20 Hz). In addition, it is shown that more than 4 million of working cycles can be attained if the maximum applied stress is kept below a threshold of about 200 MPa. Although under this condition the deformation must remain lower than 2% a reasonable damping capacity can still be obtained.

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