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101.
Cantilever steel beams of uniform strength are having various industrial applications. In particular when it is used as leaf
spring it undergoes very large deflection in comparison to beam of uniform cross section. The damage occurs in these beams
mainly due to fatigue loading. Early detection of damage in such type of beams is very essential to avoid a major failure
or accident. In this paper, firstly formulation of an objective function for the genetic search optimization procedure along
with the residual force method are presented for the identification of macroscopic structural damage in an uniform strength
beam. Two cases have been investigated here. In the first case the width is varied keeping the strength of beam uniform throughout
and in the second case both width and depth are varied to represent a special case of uniform strength beam. The developed
model require experimentally determined data as input and detect the location and extent of the damage in the beam. Here,
experimental data are simulated numerically by using finite element models of structures with inclusion of random noise on
the vibration characteristics. It has been shown that the damage may be identified for the said problems with a good accuracy. 相似文献
102.
Grain growth behaviour of fine (∼3 μm) and attrition milled nanocrystalline (∼32 nm) titanium powers during sintering have been studied. The activation energies of grain growth (Q
g) in fine titanium were found to be 192.9 and 142.4 kJ/mol at lower and higher temperature ranges, respectively. The nanocrystalline titanium showed very low values of Q
g (54.6 kJ/mol) at lower temperatures and it increased to 273.2 kJ/mol at higher temperatures. The constant (n) in nano Ti system was found to have unusually very high values of 6.5–8.2. The grain boundary rotation along with the diffusional processes could be the grain growth mechanism in nanocrystalline and in fine titanium powders. 相似文献
103.
The light-like linear dilaton background presents a simple time dependent solution of type II supergravity equations of motion that preserves 1/2 supersymmetry in ten dimensions. We construct supergravity D-brane solutions in a linear dilaton background starting from the known intersecting brane solutions in string theory. By applying a Penrose limit on the intersecting (NS1–NS5–NS5′)-brane solution, we find out a D5-brane in a linear dilaton background. We solve the Killing spinor equations for the brane solutions explicitly, and show that they preserve 1/4 supersymmetry. We also find a M5-brane solution in eleven-dimensional supergravity. 相似文献
104.
Sudipa Panigrahi Subrata Kundu Sujit Ghosh Sudip Nath Tarasankar Pal 《Journal of nanoparticle research》2004,6(4):411-414
Sugar-assisted stable monometallic nanoparticles were synthesized by wet chemical method following a general scheme. Judicious manipulation of the reducing capabilities of different sugars has shown to have a bearing on the particle size that corroborates the shift of the absorbance peak positions and TEM analysis. Evaporation of the precursor solutions on the solid surface (strong metal--support interaction), led to the formation of smaller particles. Under the experimental condition, spherical nanoparticles of approximately 1, 3, 10 and 20 nm sizes were prepared reproducibly for gold, platinum, silver and palladium, respectively. Fructose has been found to be the best suited sugar for the synthesis of smaller particles and remained stable for months together. 相似文献
105.
The Aurivillius phase-based composition bearing chemical formula Bi4Pb2Zr2TiFeNbO18 (termed as BPZTFNO) was synthesized by a solid-state method. The structural analysis as obtained from the X-ray pattern has depicted an orthorhombic phase. The various size and morphology of grains are distributed throughout the natural surface as revealed from microstructure analysis. The dielectric and electrical study of the BPZTFNO is taken at a various sweep of frequency (1 kHz–1 MHz) and temperatures (25–400 °C). The ferroelectric-paraelectric phase transition is well illustrated from the temperature-dependent dielectric constant. The complex impedance analysis suggests the association of grain effect. The relaxation of non-Debye nature is shown in the impedance study. The formed sample is subjected to an electric field and further its excitation performance is examined suggesting its possible usage in devices. 相似文献
106.
Sudip Nath Sujit Kumar Ghosh Subrata Kundu Snigdhamayee Praharaj Sudipa Panigrahi Tarasankar Pal 《Journal of nanoparticle research》2006,8(1):111-116
A detailed comparison of the softness of gold and silver has been reported in the light of hard soft acid base (HSAB) principle. Gold and silver nanoparticles in organic media (i.e., organosol) have been exploited individually to establish the principle. Sulfur and nitrogen were employed as soft and borderline donating atoms to examine the metal-ligand interactions. In this regard, thiols and amines have been considered as interacting ligands with sulfur and nitrogen donor atoms respectively. The stronger affinity of gold towards softer sulfur donor as compared to nitrogen and conversely a reasonable interaction of silver nanoparticles with both the atoms authenticate the softer nature of gold nanoparticle as compared to silver one. 相似文献
107.
Pratima Panigrahi 《Designs, Codes and Cryptography》1998,13(2):187-198
The result of the title was conjectured by F. De Clerck and V. D. Tonchev (Partial geometries and Quadrics, Sankhya, special volume 54 (1992), 137–145). We prove it here. 相似文献
108.
Several supergravity solutions corresponding to bothDp, as well asDp—Dp′ systems, inNS-NS andR-R pp-wave background originating fromAdS
3 xS
3 xR
4 are presented. The supersymmetry properties of these solutions are analysed along with a brief outline of the world sheet
construction for thep — p′ branes. 相似文献
109.
110.
N. Suriyamurthy B. S. Panigrahi K. Dukenbayev Annapurna Rout S. K. Sekatskii G. Dietler 《辐射效应与固体损伤》2013,168(2):146-152
Photostimulable phosphor CsBr:Eu2+ is prepared through a solid-state reaction. The effect of annealing atmosphere on photoluminescence and photostimulated luminescence was investigated. Optimum luminescence intensity was obtained when samples were prepared at 350°C in air atmosphere. The effect of irradiation of gamma and neutron had resulted in the formation of optically stimulable traps with different trap depths. The role of monovalent and divalent dopants on thermoluminescence dosimetric properties has been discussed. 相似文献