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The aim of this study was to determine the effect of ultrasound waves on mechanical properties of organic bread. Mixed grain bread baked at a local bakery according to its original recipe was the material subjected to testing. Prior to baking, the dough was sonicated at frequencies of 20 kHz and 40 kHz for 3 minutes, and at a frequency of 100 kHz for 3 minutes and 6 minutes. The mechanical properties of the bread (compression test, penetration test and TPA) were examined after 24 h, 48 h and 72 h following the baking process. The maximum work obtained in the compression test after 24 h following the baking ranged from 616 N to 668 N. On the next day following the baking, the maximum work value ranged from 750 N to 898 N, while after 72 hours, it ranged from 988 N to 1135 N. In the penetration test, the following results were obtained: after 24 hours, the force value ranged from 2.71 N to 3.17 N; after 48 hours following the baking, it ranged from 4.90 N to 6.35 N; and after 72 hours following the baking, from 3.98 N to 6.88 N. As regards elasticity, the obtained results fell within the following ranges: after 24 hours following the baking, from 0.53 to 0.58; after 48 hours following the baking, from 0.43 to 0.55; and after 72 hours following the baking, from 0.40 to 0.45. Gumminess measured after 24 hours following the baking ranged from 8.75 N to 18.71 N; after 48 hours, from 10.83 N to 15.48 N; and after 72 hours, the gumminess values ranged from 15.57 N to 19.06 N. As regards chewiness, the following results were obtained: after 24 hours following the baking, from 8.00 N to 17.59 N; after 48 hours following the baking, from 9.77 N to 13.87 N; and after 72 hours following the baking, from 12.56 N to 16.85 N. The frequencies and durations of sonication applied changed no mechanical properties of the tested bread.

An analysis of the risk of failure in the safety valve – tank with propane-butane (LPG) system has been conducted. An uncontrolled outflow of liquid LPG, caused by a failure of the above mentioned system has been considered as a threat. The main research goal of the study is the hazardous analysis of propane-butane gas outflow for the safety valve – LPG tank system. The additional goal is the development of an useful method to fast identify the hazard of a mismatched safety valve. The results of the research analysis have confirmed that safety valves are basic protection of the installation (tank) against failures that can lead to loss of life, material damage and further undesired costs of their unreliability. That is why a new, professional computer program has been created that allows for the selection of safety valves or for the verification of a safety valve selection in installations where any technical or technological changes have been made.