Study of passenger subjective response to ideal and real-vehicle vibration environments

The stimulus received by subjects tested on the passenger ride quality apparatus (PRQA) is defined. Additional analyses on the data collected from field tests using buses, were conducted to assess the relation between subjective ratings of ride quality and vibrations measured on the buses, and to better define the vibration stimulus measured in the field. The relation of subjective evaluation of simulations of bus rides produced by the DRQA to subjective evaluations of the actual bus rides is discussed. The relative contribution of the seat and floor vibration to human comfort in a simulated aircraft ride environment is discussed along with the determination of equal comfort curves through magnitude estimation

Development of ride comfort criteria for mass transit systems

Two studies were conducted on the effects of simultaneous sinusoidal vibration in the vertical and lateral axes on ratings of discomfort in human subjects in a simulated passenger aircraft. In the first experiment each of 24 subjects experienced each of ten levels of vertical frequency in combination with each of ten levels of lateral frequency vibration and rated the discomfort produced on a nine-point, unipolar scale. In the second experiment 72 subjects experienced one of four levels of vertical frequency at each of four levels of vertical amplitude combined with 16 (or 4 x 4) lateral frequency and amplitude conditions. The results of these two studies strongly suggest that there are effects on discomfort that occur when subjects are vibrated in several axes at once that cannot be assessed with research using vibration in only one axis

Numerical Modeling of Magnetic Field Deformation as Related to Susceptibility Measured with an MR System

The possibility is studied of numerical modeling of magnetic field deformations in the environment of measured diamagnetic and paramagnetic samples for the purposes of studying magnetic resonance (MR) image deformations owing to the susceptibility of heterogeneous materials (objects). The verification was realized using a simple sample configuration (circular plate), and the numerically modeled cross-sections were compared with the experimentally obtained values of the magnetic field measured by the MR gradient echo technology. The results show that it is possible – via a technical calculation – to determine a magnetic field deformation in the environment of complex-shaped or non-homogeneous structures in the MR experiments

Effect of vibration in combined axes on subjective evaluation of ride quality

The effects of simultaneous sinusoidal vibration in the vertical and lateral axes on ratings of discomfort were investigated. The first experiment concentrated on the effects of variation of frequency in the two axes, and the second study concentrated on the effects of amplitude variation in the two axes

MRI-Based Visualization of the Relaxation Times of Early Somatic Embryos

The large set of scientific activities supported by MRI includes, among others, the research of water and mineral compounds transported within a plant, the investigation of cellular processes, and the examination of the growth and development of plants. MRI is a method of major importance for the measurement of early somatic embryos (ESE) during cultivation, and in this respect it offers several significant benefits discussed within this paper. We present the following procedures: non-destructive measurement of the volume and content of water during cultivation; exact three-dimensional differentiation between the ESEs and the medium; investigation of the influence of ions and the change of relaxation times during cultivation; and multiparametric segmentation of MR images to differentiate between embryogenic and non-embryogenic cells. An interesting technique consists in two-parameter imaging of the relaxation times of the callus; this method is characterized by tissue changes during cultivation at a microscopic level, which can be monitored non-destructively