Preface

Papers published in this special issue have been presented during the International Conference on Inverse Problems in Engineering 2014 (ICIPE2014) which took place in Kraków, Poland, in May, 2014. The ICIPE2014 was the 24th in the series of national and international meetings on inverse problems that were initiated at Michigan State University in 1988. The 2014 edition is the 8th International Conference. Both the scientific committee members and the participants come from many countries worldwide: USA, Brazil, Russia, Poland and France, among others. The primary purpose of the Conference is to provide a forum of scientist and graduate students in sciences and engineering with recent results of the inverse problems. The topics of the Conference cover inverse problems in all branches of science and engineering including thermal sciences, structure mechanics, fluid flows, medical applications and many others. This special issue of Numerical Methods for Heat & Fluid Flow (NMHFF) contains, however, only papers dealing with inverse thermal problems. During the Conference, six keynote lectures have been delivered by eminent scientists. These lectures were accompanied by presentations of 96 regular papers. The issue containing 13 contributions starts with the paper by McMasters et al., entitled Testing Extremely Small Samples Using the Flash Diffusivity Method. The paper examines the effects of the sample holder and the contact resistance on the measured thermal diffusivity of the sample and includes experimental results of laboratory measurements. In the research, very small-sized samples of approximately 2 mm in diameter are examined. For samples of this size, the holder has to make a good contact with the entire perimeter surface of the sample, and the sample is held in place by means of friction. This requires a mathematical model for the direct solution which accommodates the holder and a contact resistance between the holder and the sample. Second paper entitled An Alternative Approach to Thermal Analysis using Inverse Problems in Aluminum Alloy Welding is by C.P. da Silva. This article proposes an alternative for the thermal analysis of the TIG (tungsten inert gas) welding process on a 6060 T5 aluminium alloy. For this purpose, a C code was developed, based on a transient three-dimensional heat transfer model. To estimate the amount of heat delivered to the plate, the Specification Function technique was used. Laboratory experiments were carried out to validate the methodology. A new experimental methodology is proposed to estimate the emissivity radiation coefficient. The proposed methodology proved to be a cheap way to estimate the heat input to the sample. The estimated power curves for the welding process are presented. The methodology to determine the emissivity coefficient was validated. Next paper by Bozzoli et al. is entitled Estimation of the Local Heat Transfer Coefficient in Coiled Tubes: Comparison Between Tikhonov Regularization Method and Gaussian Filtering Technique. In the paper, the applications of the solution techniques of the inverse heat conduction problem are shown. This enables estimation of the local convective heat transfer coefficient inside a pipe. In the paper, two different techniques were considered and compared: Tikhonov regularization method (TRM) and Gaussian filtering technique (GFT). They were tested considering particular problems within passive heat transfer enhancement techniques: estimating the local convective heat transfer coefficient inside coiled tubes. The comparison carried out using both Preface