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The article presents calculations of the theoretical efficiency of the spark ignition engine cycle. Calculations of the efficiency of the Otto cycle were carried out with the use of throttling to a certain value of manifold vacuum in relation to atmospheric pressure, which is to simulate the operation of a real engine in the partial load range. The determined efficiency is the benchmark for determining the efficiency of the same cycle with a decreasing of throttling by adding an inert gas in the form of argon. This approach, apart from limiting the pumping work in the comparative cycle, increases the isentropic exponent in the compression and expansion processes, and thus translates into an increase in the efficiency of the considered cycle. The calculations were performed for various ranges of throttling pressure with the use of air and air with argon addition. The results are compiled in the form of a 3D diagram, taking into account the limiting ranges of throttling pressures and maintaining the ratio of argon mass to air mass at a certain level not exceeding 20% of the air mass involved in the process. Up to about 5.4% increase in the cycle efficiency was observed with an argon addition of 20% by weight. The obtained results are the basis for conducting research on a real object.

Objective Conjugated linoleic acid (CLA) is known as a potent agent for altering body weight and composition. However, its effect on the process digestion is still unknown. The aim of this study has been to elucidate the effect of 3 month supplementation with CLA on starch and fat digestion and absorption in humans. Research methods & procedures The study included 74 obese and overweight adults who were randomized to receive daily 3.0g CLA or sunflower oil as placebo for 3 months. Digestion and absorption of fat and starch was assessed using non-invasive breath tests with a stable lsupg13l/supgC isotope (cumulative percentage dose recovery - CPDR) before and after the supplementation period. To exclude the effect of oxidation, in addition total energy expenditure (TTE) was measured by lsupg13l/supgC bicarbonate breath test. Results The changes in CPDR values (∆CPDR medianlinterquartile rangeg) were not different between subjects from CLA group and placebo group (fat: -0.2 l-9.1 4.1g vs. 0.6 l-7.0 8.0g, pl0.4796; starch: -1.3 l-9.5 2.4g vs. -1.0 l-5.1 1.7g, pl0.5520, respectively). The incidence of negative and positive values of ∆CPDR was not different between groups [for fat: 53.1% vs 46.7%, RR 1.138, (95 % CI 0.689-1.882) and for starch: 67.7% vs 56.7%, RR 1.195, (95 % CI 0.804-1.777)]. The changes of TTE did not differ between CLA and placebo group (respectively 1 l48; 267g vs. -8 l-120;93g kcal; pl0.2728). Conclusion Supplementation of CLA for three months did not affect fat and starch digestion assessed by lsupg13l/supgC mixed triglyceride breath test and lsupg13l/supgC starch breath test.