http://nopr.niscair.res.in/handle/123456789/14637 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/14656 Title: Free vibration analysis of thick plates on elastic foundations using modified Vlasov model with higher order finite elements <br/> <br/>Authors: Ozgan, Korhan <br/> <br/>Abstract: <span style="mso-ansi-language:EN-US" lang="EN-US">This study is concerned with the free vibration analysis of thick plates on elastic foundation using modified Vlasov model. The effects of the subsoil depth, aspect ratios, the ratio of subsoil depth to span of the plate and the value of the vertical deformation parameter within the subsoil on the frequency parameters of plates on elastic foundations are investigated. An eight-noded, 24 degrees of freedom quadrilateral finite element (PBQ8) based on Mindlin plate theory is used for the analysis. The first six natural frequency parameters are presented to show the effects of the parameters considered in the study. It is concluded that the subsoil depth is more effective on the frequency parameters of plates resting on elastic foundation than the other parameters considered in this study. </span> <br/> <br/>Page(s): 279-291 Sun, 29 Jul 2012 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/14655 Title: Estimation of the flash points of saturated and unsaturated hydrocarbons <br/> <br/>Authors: Keshavarz, M H <br/> <br/>Abstract: This work introduces a novel, reliable and simple correlation for predicting the flash point of various types of saturated and unsaturated hydrocarbons containing cyclic and acyclic paraffins, olefins, alkynes and aromatic hydrocarbons. It is shown that the new method is based on the number of carbon and hydrogen atoms and some specific molecular moieties, which can easily be used for any types of hydrocarbons. The largest available experimental data consisting of 441 diverse hydrocarbons are used here in order to derive and test the general correlation. For a data set containing 423 of these 441 hydrocarbons, the root mean square (rms) and average absolute deviations are 7.7 and 5.7 K, respectively. The estimated flash points for 18 further hydrocarbons containing complex molecular structures have been compared with one of the best available new group additivity methods, which give much lower values of the rms and average absolute deviations. <br/> <br/>Page(s): 269-278 Sun, 29 Jul 2012 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/14654 Title: Simulation of non-linear viscoelastic behavior of cross-linked mesoporous silica aerogels by depth-sensing indentation <br/> <br/>Authors: Kucuk, Yilmaz <br/> <br/>Abstract: Aerogels are ultra-lightweight nanoporous materials with high thermal insulation value for industrial applications. Recently, a reinforcing process referred to as ‘crosslinking’ has been implemented to improve their mechanical properties via coating the pore structure with a nano-thin conformal polymer layer. In this study, ordered mesoporous, monolithic silica aerogels obtained by templating with a tri-block co-polymer used as surfactant, is tested by depth-sensing indentation at the room temperature, and the results are compared with simulations using the ABAQUS software package. Assuming that polymer crosslinked aerogels have non-linear viscoelastic properties due to their polymer encapsulated mesoporous structure, the Burgers model is implemented as a user-defined subroutine in the ABAQUS environment. The results clearly show that the loading-unloading curves obtained from the nanoindentation tests are in good agreements with simulation. Therefore, predictions using different loads and loading rates can be modeled by implementing Burger's model. <br/> <br/>Page(s): 260-268 Sun, 29 Jul 2012 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/14653 Title: <span style="font-size:11.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">Microstructural development on AISI 1060 steel by FeW/B₄C composite coating produced by using tungsten inert gas (TIG) process</span> <br/> <br/>Authors: Islak, Serkan; Buytoz, Soner; Karagöz, Muzaffer <br/> <br/>Abstract: <span style="mso-ansi-language: EN-US" lang="EN-US">This study discusses the effects of B₄C addition on the morphologies of primary carbides and eutectic colonies in FeW weld-surfacing alloys.<span style="mso-ansi-language:EN-US;mso-fareast-language: ZH-TW" lang="EN-US"> Results reveal that a series of FeW <span style="mso-ansi-language:EN-US" lang="EN-US">weld-surfacing<span style="mso-ansi-language:EN-US;mso-fareast-language:ZH-TW" lang="EN-US"> alloys with different B₄C contents are successfully fabricated onto AISI 1060 steel by using <span style="mso-ansi-language:EN-US; mso-bidi-font-weight:bold" lang="EN-US">tungsten inert gas (TIG) <span style="mso-ansi-language:EN-US;mso-fareast-language:ZH-TW" lang="EN-US">arc welding. <span style="mso-ansi-language:EN-US;mso-bidi-font-weight:bold" lang="EN-US">SEM observations show that the obtained coating sheet has a smooth and uniform surface, as well as a metallurgical combination with the AISI 1060 steel substrate without cracks and pores at the interface. Fe₂₃(C,B)₆, Fe₃(C,B), FeW₂B₂ and FeW₃C boride and carbides are determined in the microstructure. The microhardness values of the coating results show a difference <span style="mso-ansi-language: EN-US" lang="EN-US">depending on the<span style="mso-bidi-font-weight:bold"> rate of B₄C and coating conditions. The maximum microhardness value of the coating is about 1095 HV.<span style="mso-bidi-font-weight:bold"> </span></span></span></span></span></span></span></span></span></span> <br/> <br/>Page(s): 253-259 Sun, 29 Jul 2012 22:58:59 GMT