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The paper aims to present a new friction modifier (mixture of zinc and copper oleates) proper for industrial running-in of repaired engines.

The method of comparison was used for testing the offered friction modifier, a market product “Renom Engine” and a blank sample of motor oil as an etalon. Running-in time has been established. The mechanical losses change and the relevant coefficients have been determined. Data of the bearings wear have been included.

The benefit of the metal oleates and Renom Engine usage as friction modifiers has been proved. Time for industrial cold running-in of repaired engines decreases by around 20 per cent when friction modifiers are used in comparison with the etalon oil. The coefficient of the mechanical losses reduction at running-in with friction modifiers is higher than the coefficient for the etalon oil. The higher coefficient values indicate that the running-in of the working surfaces occurs more intensively and for a shorter period of time. Lower wear of the bearings is combined with smaller roughness of the friction surface, which secures higher quality of the surfaces run-in with the friction modifiers and greater capacity by around 30 per cent.

This study introduces a new friction modifier for industrial running-in of repaired engines. It would be of interest to the customers and manufacturers of oil additives.

Purpose – The chapter outlines mixed methods as a recursive and co-operative approach to research. In doing so, it challenges the dominant conception of ‘real’ mixed methods research as requiring the use of methods from both qualitative and quantitative frameworks by outlining not only logistic and pragmatic issues requiring the attention of researchers but also the underlying philosophical tensions inherent in mixed method designs.

Design/methodology/approach – The process of designing a mixed methods project that investigated the sociological and phenomenological impact of running shoes is outlined with reference to the various pragmatic and epistemological considerations of the project.

Findings – Many researchers require mixed methods to draw on both quantitative and qualitative techniques. However, this chapter demonstrates that such an understanding of mixed methods marginalises critical and interpretivist techniques. It is argued that studies of sport and physical culture have frequently used more than one research method. However, in order for these to be considered mixed methods studies, an explicit attempt is required to connect each technique of data collection and analysis, regardless of the research paradigm in which they operate.

Research limitations/implications – The limitations of mixed methods designs are discussed in relation to pragmatic and logistic concerns as well as the difficulty of connecting methods that present different underlying philosophical assumptions.

Originality/value – This chapter demonstrates the design of a mixed methods project from the initial process of identifying a research problem through to data collection, analysis and publication.

Conventional tests of the regression discontinuity design’s identifying restrictions can perform poorly when the running variable is discrete. This paper proposes a test for manipulation of the running variable that is consistent when the running variable is discrete. The test exploits the fact that if the discrete running variable’s probability mass function satisfies a certain smoothness condition, then the observed frequency at the threshold has a known conditional distribution. The proposed test is applied to vote tally distributions in union representation elections and reveals evidence of manipulation in close elections that is in favor of employers when Republicans control the NLRB and in favor of unions otherwise.