Nacrtak Despite technological advancements in machinery for timber harvesting, chainsaws are fre­ quently used in forest operations. In Austria 85% of the wood volume harvested (15 million m3) are cut by chainsaws. The two most frequently documented ergonomic threats during motor manual felling include exposure to noise and vibration. This paper presents the results of exposure to hand-arm vibr...

This paper presents a reduce roll vibration of the full vehicle model with passive suspension systems using vibration absorber to change the dynamic system matrix stat’s eigenvalue. Since using the controller system has been splurged and required to energy consuming, in this research the vehicle body roll vibration has been reduced and supplied vehicle stability using a vibration absorber for t...

The paper deals with the problem of angular vibration measurements in time history of rotation angle, angular velocity or angular acceleration. The source of information about angular vibrations is an encoder producing an impulse signal. It is supposed that the impulse frequency is changed proportionally to the rotational frequency. A time record of an impulse signal is transformed to an analyt...

This article presents the development of a system integrated to a ZigBee network to measure whole-body vibration. The developed system allows distinguishing human vibrations of almost 400Hz in three axes with acceleration of almost 50g. The tests conducted in the study ensured the correct functioning of the system for the project's purpose.

Flowing gel plugging and low-frequency vibration oil extraction technology have been widely applied in low-permeability formation. High probability of overlapping in action spheres of two technologies might lead to poor operating efficiency during gel injection. Study on flowing gel rheological properties under low-frequency vibration was essential, which was carried out indoor with viscosity m...

OBJECTIVES The purpose of this study was to compare various effects on the hand-arm system of vibration exposure from a chipping hammer and a grinder with the same frequency weighted acceleration. Grip and push forces were measured and monitored during the exposure. The various effects were: muscle activity (measured with surface electrodes), discomfort ratings for different parts of the hand-a...

Multi-point independent simultaneous force measurements were made to investigate the vibration force distribution on the palm and to determine one representative point on it for the purpose of field survey. The phase relationships between the force and the acceleration were also pursued. In connection with vibration force transmission, important effects such as vector, bypassing and mechanical ...

Mechanical stimulation is an essential factor affecting the metabolism of bone cells and their precursors. We hypothesized that vibration loading would stimulate differentiation of human adipose stem cells (hASCs) towards bone-forming cells and simultaneously inhibit differentiation towards fat tissue. We developed a vibration-loading device that produces 3g peak acceleration at frequencies of ...

OBJECTIVES To investigate the occurrence of disorders associated with the hand arm vibration syndrome in a large population of stone workers in Italy. The dose-response relation for vibration induced white finger (VWF) was also studied. METHODS The study population consisted of 570 quarry drillers and stonecarvers exposed to vibration and 258 control stone workers who performed only manual ac...

− A piezoelectric accelerometer output voltage with zero shift was induced by the low-frequency response of the charge amplifier. So we designed a virtual amplifier with same input-output characteristic as the charge amplifier, and shock sensitivities of a piezoelectric accelerometer were evaluated by applying the input acceleration to the virtual amplifier. The shock sensitivities were compara...