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The study presents transmissibility responses of 14 male subjects exposed to vertical sinusoidal vibration (2.0–16.0 Hz) at five vibration magnitudes (0.5–1.5 m s−2r.m.s.). The vibration magnitudes are measured at five body locations: head (at the forehead), sternum, abdomen, thigh, and leg, for which the transmissibility at each body location is statistically analyzed. The nonlinearity in the transmissibility response, that is, decrease in resonance frequency with an increase in vibration magnitude, is evident for the sternum, abdomen, thigh, and leg. The higher vibration magnitude causes greater segmental transmissibility at excitation frequency lower than the resonance frequency. The highest vibration transmissibility has been observed for the abdomen, followed by the thigh, sternum, and head. The findings indicate that the higher energy content associated with the sinusoidal waveform further softens the tissues in contact with the vibrating surface.Practitioner Summary:The present study provides transmissibility responses of the semi-supine posture of humans at the head, sternum, abdomen, thigh, and leg under vertical sinusoidal excitation (2.0–16.0 Hz). Pronounced transmissibility is obtained for the abdomen among the other body segments, followed by the thigh, as both consist of a majority of soft tissues.

This paper presents an autonomous method to diagnose a double-row self-aligning ball bearing for any dynamic misalignment or localized defects, using vibration signals. The frequency spectra from the experimental investigation revealed that irrespective of the health condition of the bearing i.e. either healthy or defective, the frequency spectrum had a clear cage frequency peak whenever the system was under dynamic-misalignment. An improved version of Harmonic Product Spectrum (HPS) called sideband product spectrum (SPS) was used to identify the cage frequency peaks which was preprocessed using kurtosis-based band-pass filter and parameter-optimized variational mode decomposition (VMD) algorithm. A mathematical model is also presented to analyze the dynamic behavior of double-row self-aligning ball bearing under such conditions. From the model, it was realized that during misalignment, the contact load shared by the rolling elements, generates some moment which has a tendency to rotate the bearing’s inner-race about the radial axis and thus resulting in a wobbly rotary motion. This wobbly motion of the inner race in fact characterizes the bearing for dynamic misalignment. The simulated results were in accordance with the experimentally obtained results.

Legumes and pulses are plant foods, where pulses are a subgroup of legumes from the Leguminosae family and are rich in protein and minerals. They are fundamental sources of nutrition primarily for vegetarian and vegan subjects. Proteins are modified to improve properties such as solubility, dispersibility, wettability, water absorption capacity, oil absorption capacity, and emulsifying property thus increasing the range of application of protein in the food industry. The protein properties are modified by different processing techniques such as physical, chemical, and enzymatic treatments. Several non-thermal treatments have been developed to reduce the impact of thermal treatment on the food components. Ultrasonication is an extensively researched method, which is proven to reduce antinutrient levels, enhance protein digestibility, and thus improve its usage as a key functional ingredient in food products. The application of ultrasound to modify the legume proteins has gained significant interest due to its green processing concept and serves as an alternative to conventional modification techniques to improve or modify the undesirable techno-functional, structural, and physico-chemical properties. The sonication enables controlled modification of physical and chemical properties of proteins and can produce high-quality protein-rich foods. Legumes are rich in protein and are used as a key ingredients in food products such as meat analogues, meatballs, and baby foods. Therefore, it is important to improve undesirable functional properties such as texture, whippability, fat binding, and emulsification to enhance its utilization. This review comprehensively discusses the application of ultrasound treatments in modifying the techno-functional, structural, and physico-chemical properties of legume proteins.

The operating clearance in a bearing influences friction, load zone size and fatigue life of a bearing. Hence, an effort is made to investigate the effect of radial internal clearance on the dynamical behavior of a cylindrical roller bearing system with an unbalance present in the system. The differential equations representing the dynamics of the cylindrical roller bearings have been derived using Lagrange’s equations and solved numerically using the fourth-order Runge-Kutta iterative method. The nonlinear vibration signature has been analyzed due to the clearance and the same is represented by various tools like Acceleration-time plots, Poincaré plots and FFT plots. The approximation method is used to calculate the load distribution and deformation of the individual rollers located at a different position in the load zone, for a preloading/interference fit and positive internal clearance. A response surface method is used to analyze the severity involved in the system due to the combined effect of independent variables like rotor speed, radial load, and radial internal clearance. The observations presented here are not only useful to diagnose the bearing health condition with respect to parametric effects but also exhibit their interactive effects on bearing performance.

The dynamic behaviour of cylindrical roller bearings is presented, in both balanced and unbalanced conditions as a function of speed. The stiffness and damping non-linearities at the contact points (due to Hertzian contact force between rollers and races), radial internal clearance and unbalanced rotor force make the bearing system non-linear. Presently, the differential equations representing the dynamics of the cylindrical roller bearings have been obtained using Lagrange’s equation and solved numerically using modified Newmark-β method. The results of the analyses of various motion behaviours are presented as time–displacement responses, orbit plots, phase portraits, Poincaré maps and Fast Fourier Transform plots. The obtained responses revealed the sensitive behaviour of the system from periodic to quasi-periodic and chaotic with speed variations for both balanced and unbalanced rotor conditions. Also, intermittent chaotic behaviour has been observed. A pattern of the interaction between rotational and variable compliance vibration is observed with speed variations. The frequency pattern analysis (with different techniques used like phase/orbit plots and Poincaré plots) for healthy cylindrical bearing and different rotor conditions under different applied non-linearity consideration is a new attempt to analyse dynamic behaviour of the bearing. This analysis is helpful for online monitoring of fault-free cylindrical roller bearings and for studying the impact of speed on system’s dynamical behaviour.

A novel laboratory technique has been used to measure the rolling resistance of tyres using a force transducer. The effect of inflation pressure, normal load and speed has been studied for two different bias-ply tyres—with and without treads. As anticipated, the results indicate that a treaded tyre has higher value of the rolling resistance as compared with a tyre with treads removed.

This work presents the semi-analytical solution of vibration response for functionally graded materials (FGM) plates with bi-linear and parabolic variable thickness. Continuous thickness variation may affect the design of plate structure which permits to modify the stiffness properties in the utmost stressed area within the domain, considering the overall weight parameter of the structure. As a result, a better dynamic response may be revealed. The first order shear deformation theory (FSDT) has been applied for a kinematic model of the variable thick plate. The material properties were calculated by the simple power law. Accuracy of this model is confirmed by various comparisons with outcomes available in the preceding literature. Frequency factor of the plates with boundary conditions are found by changing the various parameter like material volume exponent, aspect ratio, tapered ratio and thickness ratio.

Whole-body vibrations in trains are known to affect the performance of sedentary activities such as reading, writing, sketching, working on a computer, etc. The objective of the study was to investigate the extent of disturbance perceived in sketching task by seated subjects in two postures under mono- and multi-axis Gaussian random vibration environment. The study involved 21 healthy male subjects in the age group of 23—32 years. Random vibrations were generated both in mono- and multi-axial directions in the frequency range of 1—10 Hz at 0.5, 1.0, and 1.5 m/s2rms (root mean square) amplitude. The subjects were required to sketch given geometric figures such as a circle, triangle, rectangle, and square with the help of ball-point pen under given vibration stimuli in two postures (sketch pad on lap and sketch pad on table). The deviation in distortion with respect to the given figure is represented in terms of percentage distortion. The influence of vibrations on the sketching activity was investigated both subjectively and by two specifically designed objective methods, namely, RMS (root mean square methodology) and area methods. The judgements of perceived difficulty to sketch were rated using seven-point semantic judgement scale. The percentage distortion and difficulty in sketching activity increased with an increase in vibration magnitude. Both subjective evaluation and the RMS method revealed that the task was affected more while sketching on the table. The percentage distortion was affected similarly and maximum in all the vibration directions except for the vertical, while sketching difficulty was found to be higher only with longitudinal and multi-axis vibration direction. The subjective evaluation also revealed that there was no effect of the type of entity chosen on the sketching difficulty.