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To reduce the heat load of a gas turbine blade, its surface is covered with an outer layer of ceramics with high thermal resistance. The purpose of this paper is the selection of ceramics with such a low heat conduction coefficient and thickness, so that the permissible metal temperature is not exceeded on the metal-ceramics interface due to the loss ofmechanical properties.

Therefore, for given temperature changes over time on the metal-ceramics interface, temperature changes over time on the inner side of the blade and the assumed initial temperature, the temperature change over time on the outer surface of the ceramics should be determined. The problem presented in this way is a Cauchy type problem. When analyzing the problem, it is taken into account that thermophysical properties of metal and ceramics may depend on temperature. Due to the thin layer of ceramics in relation to the wall thickness, the problem is considered in the area in the flat layer. Thus, a one-dimensional non-stationary heat flow is considered.

The range of stability of the Cauchy problem as a function of time step, thickness of ceramics and thermophysical properties of metal and ceramics are examined. The numerical computations also involved the influence of disturbances in the temperature on metal-ceramics interface on the solution to the inverse problem.

The computational model can be used to analyze the heat flow in gas turbine blades with thermal barrier.

A number of inverse problems of the type considered in the paper are presented in the literature. Inverse problems, especially those Cauchy-type, are ill-conditioned numerically, which means that a small change in the inputs may result in significant errors of the solution. In such a case, regularization of the inverse problem is needed. However, the Cauchy problem presented in the paper does not require regularization.

The goal of the research was to check whether the sender communicating in an ambiguous manner can gain the benefits in three aspects: perception of his or her image, evoking agreement with issue stand and intention to support him or her in the election. Impact of ambiguous messages was compared with the impact of messages consistent or inconsistent with participants' opinions.

Two experiments were conducted. Participants were randomly divided into three groups and each of them was presented with (1) a message supporting or (2) opposing given proposition or (3) an ambiguous message not revealing the ultimate opinion of the sender. Participants' initial views on the issues were measured. In experiment 1 an expert message concerned the building of the nuclear power plant was presented. In experiment 2 it was a politician's message about introducing the guaranteed number of parliamentary seats for women.

The results suggest that a strategy of argumentative ambiguity applied by senders may be beneficial if the point is to avoid recipients' objections. However, the consequences of ambiguity for the evaluation of sender's credibility and voters' intentions can be seen to be negative.

This research was looking for the reconcile of the contradictory results of previous research, which may have their source in the various operationalization of ambiguity. It was focused at an argumentative ambiguity (i.e. presenting different points of view without declaring support for any of the options).