http://nopr.niscair.res.in/handle/123456789/1011 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/4144 Title: Dynamic permanent deformation testing of asphalt mixes and deformation waveform analysis <br/> <br/>Authors: Tigdemir, Mesut <br/> <br/>Abstract: In this study, different specimens of hot mix asphalt (HMA) have been constructed in the laboratory and tested under repeated loading; first permanent deformation and later fatigue tests using Suleyman Demirel University Asphalt Tester equipment (SDU-Asphalt Tester). This study reports evaluation of available information about relationship between permanent deformation and fatigue cracking. Analysis of data shows that the fatigue life of the pavement may be modelled in terms of data obtained from repeated loading axial permanent deformation test results. Based on the analysis of the estimation model for fatigue life from permanent deformation testing, it is concluded that for the evaluation of HMA in fatigue characterization, repeated load axial test for permanent testing can be used in a very satisfactory manner. To be able to model the fatigue lives, in addition to conventional fatigue model parameters new parameters from repeated load permanent deformation test are taken into consideration. Hence, only by examining the permanent deformation tests, it may be possible to predict the fatigue lives of the specimens without carrying out time-consuming fatigue tests. <br/> <br/>Page(s): 29-35 Tue, 29 Jan 2008 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/1034 Title: Properties of adhesive joint of inorganic nano-filler composite adhesive <br/> <br/>Authors: Ghosh, P K; Nukala, S K <br/> <br/>Abstract: The characteristics of adhesive joints of aluminium sheet containing epoxy based composite adhesives containing nano-filler of ZrO₂ powder have been studied. The composite adhesives containing 10, 15 and 20wt.% of about 20±3 nm size ZrO₂ powder are applied to mechanically treated aluminium substrates. The single lap joints of the composite adhesive are characterized by their tensile lap shear strength as a function of the bond-line thickness as well as the amount of filler. The characteristics of the composite adhesive joint have been compared to those of the conventional epoxy adhesive joints. The bond-line thickness of the adhesive with respect to the amount of the ZrO₂ nano-filler has been optimised for maximum tensile single lap shear strength of the adhesive joint of mechanically treated aluminium substrate. In comparison to conventional epoxy adhesive joints, the nano-filler epoxy based adhesive joint of aluminium shows significantly improved lap shear strength as a function of bond line thickness of adhesive and amount of filler in it. <br/> <br/>Page(s): 68-74 Tue, 29 Jan 2008 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/1033 Title: Synthesis and characterization of Mn doped PZT ceramics <br/> <br/>Authors: Yadav, K L; Sharma, Pallavi <br/> <br/>Abstract: In the present work, the effect of Mn doped PZT ceramics with composition Pb(Zr₀․₅₂Ti₀․₄₈)O₃ + x wt.% of MnO₂, (where x =0, 1, 2 and 3) has been reported. The samples are prepared by employing a simple co-precipitation technique using nitrates of lead, zirconium and titanium isopropoxide. X-ray diffraction studies confirm the formation of pure phase and homogeneous ceramics of tetragonal symmetry. Scanning electron micrographs shows a uniform grain distribution and the grain size and shape are modified upon Mn addition. Increase in Mn content causes a decrease in average grain size of the material. Dielectric measurements demonstrate a decrease in the dielectric constant and increase in dielectric loss with increase in Mn. The dielectric dispersion is large for the higher concentration of Mn ions in PZT at lower frequencies and is attributed to the space charge accumulation. The undoped and Mn doped PZT ceramics exhibit the hysteresis loops which confirms the ferroelectric behaviour. The prepared ceramics have very low dielectric loss, high dielectric constant and high transition temperature which may be useful for device application. <br/> <br/>Page(s): 61-67 Tue, 29 Jan 2008 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/1032 Title: Synthesis and characterization of Mn₀․₄Zn₀․₆Al₀․₁Fe₁․₉O₄nano-ferrite for high frequency applications <br/> <br/>Authors: Mathur, Preeti; Thakur, Atul; Singh, M <br/> <br/>Abstract: Nano-ferrite of composition Mn₀․₄Zn₀․₆Al₀․₁Fe₁․₉O₄ synthesized by co-precipitation method has been reported. The structural studies have been made by using X-ray diffraction (XRD) technique and scanning electron microscopy (SEM), which confirms the formation of single spinel phase and nanostructure. The dc resistivity is studied as a function of temperature and values are found about two times more than those for the samples prepared by the other chemical methods due to stoichiometric composition and better crystal structure of the ferrite. Even at nanolevel, the value of initial permeability is found to be 495 and low magnetic losses make these ferrites especially suitable for high frequency applications. The particle size is calculated using Scherrer’s equation for Lorentzian peak, which comes out between 32-43 nm. Possible mechanisms contributing to these processes have been discussed. <br/> <br/>Page(s): 55-60 Tue, 29 Jan 2008 22:58:59 GMT