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- Bhiwapurkar, M. K., et al.
(författare)
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Effect of magnitudes and directions (mono-axis and multi-axis) of whole body-vibration exposures and subjects postures on the sketching performance
- 2011
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Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - 0954-4097 .- 2041-3017. ; 225:F1, s. 71-83
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Tidskriftsartikel (refereegranskat)abstract
- 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/s(2) rms (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.
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| 2. |
- Bhiwapurkar, M. K., et al.
(författare)
-
Influence of Mono-axis Random Vibration on Reading Activity
- 2010
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Ingår i: Industrial Health. - 0019-8366 .- 1880-8026. ; 48:5, s. 675-681
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies on train passengers' activities found that many passengers were engaged in some form of work, e.g., reading and writing, while traveling by train. A majority of the passengers reported that their activities were disturbed by vibrations or motions during traveling. A laboratory study was therefore set up to study how low-frequency random vibrations influence the difficulty to read. The study involved 18 healthy male subjects of 23 to 32 yr of age group. Random vibrations were applied in the frequency range (1-10 Hz) at 0.5, 1.0 and 1.5 m/s(2) rms amplitude along three directions (longitudinal, lateral and vertical). The effect of vibration on reading activity was investigated by giving a word chain in two different font types (Times New Roman and Anal) and three different sizes (10, 12 and 14 points) of font for each type. Subjects performed reading tasks under two sitting positions (with backrest support and leaning over a table). The judgments of perceived difficulty to read were rated using 7-point discomfort judging scale. The result shows that reading difficulty increases with increasing vibration magnitudes and found to be maximum in longitudinal direction, but with leaning over a table position. In comparison with Times New Roman type and sizes of font, subjects perceived less difficulty with Anal type for all font sizes under all vibration magnitude.
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| 3. |
- Bhiwapurkar, M. K., et al.
(författare)
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Study of human comfort under thermal and vibratory environment using physiological indices
- 2009
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Ingår i: 16th International Congress on Sound and Vibration 2009, ICSV 2009. - 9781615677368 ; , s. 4376-4383
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Konferensbidrag (refereegranskat)abstract
- Besides the vibrations, passenger discomfort is influenced by various other factors such as, the environmental factors of noise, temperature, humidity and visual stimuli, etc. The discomfort can be measured both subjectively and objectively. Rammohan25 studied the influence of backrest support and handgrip contractions on acute metabolic, respiratory, and cardiovascular responses during exposure to whole-body vibration (WBV). In the present work, discomfort of passengers subjected to whole body random vibrations, environmental factors such as temperature, humidity and noise level variations by assessing their effect on various physiological parameters like, Pulse Rate, Respiration Rate, Galvanic Skin Response, Skin Temperature, Heart Rate, Heart Rate Variability and ECG values has been studied. The study was conducted on the three axes vibration simulator developed in the Laboratory, IIT Roorkee, India as a mock-up of a railway vehicle. The simulator room has a controlled temperature and humidity environment and its noise level can also be controlled. A BIOPAC system was used for data acquisition along with various modules for measuring physiological parameters. The mean and standard deviation of physiological parameters, possibly indicating the human comfort or discomforts for the 12 subject is found out. The design of experiment (ANOVA) was employed to quantify the relationships between measured responses and the input factors. The results show that some physiological parameters viz, pulse rate, SKT and HR show variation in vibration condition at 0.6 m/s2. It is also found that all the parameters affected by noise level and temperature show significant variation between no vibration condition and vibration condition.
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