Cavitation in kinetic pumps causes deterioration of the performance, damage of the pump, vibration in noise. Therefore, cavitation in a pump must be prevented. To prevent cavitation in a pump we have to know the beginning and development of the cavitation in the pump. For this purpose, the emitted noise in the audible range can be used. Experiments have shown that there is a discrete frequency tone within the audible spectra, which can be used to detect the incipient of cavitation and its development as well as to prevent the cavitation process in the pump.
COBISS.SI-ID: 10815771
Experiments have shown that there is a discrete frequency within the audible noise spectra, which is in strong correlation with the development of the cavitation in the pump. In this study, we wanted to clarify the mechanism of noise generation, which is responsible for the discrete frequency component and on which cavitation has an important effect. Experiments have shown that the characteristic discrete frequency, which is in close correlation with the cavitation process, is a result of structural vibrations caused by implosion of bubbles and bombardment of the inner surfaces of the pump.
COBISS.SI-ID: 10947099
Firecracker explosions have characteristics of an impulse noise, therefore they can cause hearing loss, serious personal injuries, fire hazards, annoyance, and even death. Their peak sound pressure levels at a distance of some meters can exceed the limit value of 140 dB, at which hearing protection is necessary. This article deals with some noise aspects resulting from firecracker explosions, which were measured during New Year's Eve. A special emphasis is given to the probability distribution function of peak sound pressure levels, originating from a great number of firecracker explosions.
COBISS.SI-ID: 11151643
This paper deals with the effects of ageing on driving capability. These effects were assessed by using a simulator and some points of view showing a decrease in capability of the older drivers in street traffic. This research makes an important contribution to the study of decreased driving capability with ageing and suggests the need for a selection made by health care institutions, particularly after the age of 65. This is the first research of its kind conducted in Slovenia.
COBISS.SI-ID: 7993929
Information about vibrating modes of noise source surface is needed during the design of noise control measures. In presented article two measurement methods for vibration mode visualization were compared: a surface velocity measurement using an accelerometer and a microphone scanning in a very near field. A 380 mm square steal plate with thickness of 2.9 mm, with completely free boundary conditions, was excited using a shaker. Results of scanning with pressure microphone in a very near acoustic field provide pictures of mode shapes with good spatial resolution.
COBISS.SI-ID: 10963483