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Preliminary assessment of vibration impacts generated by the public transport systems on pregnant women based on subjective reactions

Kromka-Szydek M., Dziechciowski Z., Tyrpin P.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 1

79--92

EN

Research efforts summarised in this study were a part of preliminary investigation to evaluate the impact of pregnant women’s exposure to vibrations generated by public transport system when using. Methods: The assessment of the problem and discomfort for pregnant women, caused by the public transportation is based on a questionnaire including questions relating to the women’s subjective feelings on well-being or discomfort when exposed to vibration during the ride in passenger cars or when using means of public transport. In the second stage of investigation, vibrations transmitted onto a sitting person during the tram or car ride were measured. Results: The survey shows that when travelling on a tram the women complained mostly of digestive or neurological disorders, during the car ride they suffered most acutely from digestive disorders, sensed enhanced foetus movements and reported problems with the osteoarticular system. Amplitude-frequency characteristics of the investigated vehicle types reveal that vibration amplitudes registered during the ride in a motor vehicle are higher than on tram (in the analysed frequency range). Furthermore, vibration accelerations in the z-axis direction registered during the tram ride exceed the vibration discomfort threshold, particularly for the 1/3 octave bands 5 and 6.3 Hz. These are frequency ranges corresponding to resonance frequencies of vital organs in the abdominal cavity (4.5–10 Hz). Conclusions: Correlating these results with frequencies reported in literature associated with subjective human responses to vibration, shows that pregnant women using public transport are likely to suffer from a variety of ailments caused by vibrations generated during the ride.

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Uncertainty analysis of the determination noise source direction using the tetrahedron hydrophone array

Gloza I., Józwiak R., Pawlik P., Bartko W.

Hydroacoustics

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2015

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Vol. 18

59-68

EN

The analysis of the uncertainty of the determination of the noise source direction in the aquatic environment is presented in this paper. The type A uncertainty of the bearing algorithm was determined on the bases of multiple measurements of the hydroacoustic pressure by means of the TC4032 type hydrophones and the GPS device data. The influence of the non-linearity of the amplitude-frequency characteristic on the uncertainty of the determination of the noise source direction, was also described. The influence of water density, electromagnetic disturbances and irregular noises on the final uncertainty was determined. On the bases of the determined uncertainty components the uncertainty budget, of the determination of the angle showing the direction from which hydroacoustic waves are coming, was prepared.

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Experimental research on the influence of the production quality of tooth operation surfaces of cylindrical gearwheels and torque on a gear oscillation amplitude

Vasyljeva O., Kuzio I.

ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes

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2014

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Vol. 3, No 2

79--86

EN

For carrying out experimental research a proving stand with closed power flow was designed. For the determination of oscillation process parameters (amplitude and frequency) the devices with input signals from strain sensors were used. Planning the experimental research and mathematical treatment of the results obtained was performed with the use of a full factorial experiment. The results of the experiment allowed for obtaining a nonlinear mathematical model for determining the oscillation amplitude and the amplitudefrequency characteristic of gear box oscillations (first harmonic). It then is used for determining the harmonic of the oscillating process caused by the inaccuracy of a tooth operating profile, which influences the smoothness of gear operation. The dependences taking into account internal and external dynamic loads from oscillating processes during the calculations of teeth gear hardness were obtained.