This paper reports the results of experimental investigations on the influence of the addition of cerium oxide in the nanoparticle form on the major physicochemical properties and the performance of biodiesel. The physicochemical properties of the base fuel and the modified fuel formed by dispersing the catalyst nanoparticles by ultrasonic agitation are measured using ASTM standard test methods. The effects of the additive nanoparticles on the individual fuel properties, the engine performance, and emissions are studied, and the dosing level of the additive is optimized. Comparisons of the performance of the fuel with and without the additive are also presented. The flash point and the viscosity of biodiesel were found to increase with the inclusion of the cerium oxide nanoparticles. The emission levels of hydrocarbon and NOx are appreciably reduced with the addition of cerium oxide nanoparticles.

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SUMMARYA review of recent investigations on micro heat pipes of various geometrical designs, fabrication methods, operational environments and applications is presented, along with a comparative analysis of the performance of various designs, based on quantitative design parameters and performance indicators. A comprehensive report of the salient features of these investigations has been presented in a tabular form, in order to provide a quick reference of the state-of-the-art of micro heat pipe research. Both theoretical and experimental investigations have been included in this review, with special attention given to some of the new concepts and proposed designs for micro heat pipes, currently under development.

Nanoparticle suspensions (nanofluids) have been recommended as a promising option for various engineering applications, due to the observed enhancement of thermophysical properties and improvement in the effectiveness of thermal phenomena. A number of investigations have been reported in the recent past, in order to quantify the thermo-fluidic behavior of nanofluids. This review is focused on examining and comparing the measurements of convective heat transfer and phase change in nanofluids, with an emphasis on the experimental techniques employed to measure the effective thermal conductivity, as well as to characterize the thermal performance of systems involving nanofluids.

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W~i r m eu n d S t o f f O b e r t r a g u n g© Springer -Verlag 1990 Experimental studies on steady free convection heat transfer from fins and fin arrays C. B. Sobhan, S. P. Venkateshan and K. N. Seetharamu, Madras, IndiaAbstract. This paper deals with an experimental study of free convective heat transfer from fins and fin arrays attached to a heated horizontal base. The technique of differential interferometry has been utilised and experiments have been carried out under steady state conditions. Local values of heat flux, temperature, heat transfer coefficients, local and overall Nusselt numbers have been estimated. An attempt has been made to discuss in detail the flow and heat transfer mechanisms for three cases namely an isothermal vertical fiat plate, a single fin attached to a heated horizontal base and a fin array in the light of the experimental findings. Correlations are presented relating the overall Nusselt number with the relevant non-dimensional parameters in these cases. Experimenteile Studien iiber station/ire W/irmeiibertragung mittels freier Konvektion an Rippen uud Rippenfelderngusammenfassung. Diese Abhandlung beschfiftigt sich mit einer experimentellen Studie fiber freie konvektive W/irmefibertragung yon Rippen und Rippenfeldern, die an eine erwfirmte horizontale Grundfl/iche angebracht sind. Es wurde die Technik tier differentiellen Interferometrie verwendet. Die Versuche sind unter konstanten Zustandsbedingungen ausgeffihrt worden. Lokale Werte des Wfirmestroms, der Temperatur, des W/irmefibertragungskoeffizienten sowie lokale und mittlere Nusseltzahlen sind bestimmt worden. Der StrSmungs-und W/irmefibertragungsmechanismus wurde an drei F/illen detailliert untersucht: n/imtich eine isotherme vertikale ebene Platte; eine einzelne Rippe, angebracht an einer beheizten horizontalen Grundfl/iche und ein dem Strahlengang entsprechend angeordnetes Rippenfeld. Ffir diese drei F/ille werden die Berechnungen der mittleren Nusseltzahl in Abh/ingigkeit der relevanten dimensionslosen Parameter dargestellt.