Perception and Psychophysics 17, 460–464

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HUMAN RESPONSE TO VIBRATION

a prototype purpose-built ambulance, and a private car. Moreover the condition of some patients may be affected by the motion of the vehicle either directly or indirectly. Even though they form a small percentage of the total number carried, they represent a very considerable financial risk. A personally conducted survey of ambulance chief officers showed a deep interest and involvement in the upgrading of the service with a general dissatisfaction with many of the vehicles currently available. Hence there is a market for the purpose-built ambulance, which would benefit the patient and the ambulanceman alike, The inadequacies of many vehicles currently in use as ambulances have been shown to work against the interests of the patient requiring life support treatment, and it is suggested that this warrants urgent attention and action. A more extensive research project involving medical observations on the supine sick and injured, attendant task performance, and instrumentation analysis of linear and angular vehicle motions should enable the harmful effects of ride motion to be identified. None of these investigations, however, will be of any value unless they are used in developing future ambulances. Such development must also parallel an increase in the awareness of the importance of ambulance design and its relation to the increased comfort and chance of survival of the patients carried. Topics: Ride (Road Vehicles); Physiological Eflects (in General); Performance Effects; Vibration Measurements (Road Vehicles). L. F. Strikeleather 1973 Society of Automotive Engineers Paper 730823. Evaluating the vibration and shock isolation qualities of operator seats for construction machinery. (14 pages, 24 figures, 1 table, 17 references) Author’s Abstract. Since vehicle seats interact dynamically with the human body, testing the response characteristics of such seats for proper application is important. Likewise, the methods and techniques used for such evaluations are equally important if meaningful results are to be obtained. This paper discusses two quantitative test procedures applicable primarily to judging the relative performance of several seats with regard to dynamic characteristics. In particular, the equipment and procedures necessary to plot seat transmissibility are discussed and specific example data are shown for two suspension seats and a static cushion seat. Also, equipment and procedures assessing the relative dynamic response index (DRI) are discussed and example results for a suspension seat and a cushion are included. Topics : Seating; Complex Vibration (Impulse). M. Guirao and J. A. Valciukas 197.5 Perception and Psychophysics 17, 460464. Perceived vibration and the loudness of low-frequency tones. (5 pages, 6 figures, 22 references) Authors’ Abstract. Vibration and low-frequency tones were scaled for loudness by two numerical estimation procedures and by cross-modality matching. The same ranges of frequencies, from 30 to 250 Hz, were delivered to the ear and to the fingertip. For vibratory loudness, two sets of power functions were obtained, of which the low-frequency set was somewhat steeper. Tonal loudness gave a family of power functions of approximately the same slope at all frequencies tested. For frequencies above 100 Hz, the growth of loudness is about the same for both modalities. Below this frequency, vibratory loudness grows more rapidly than tonal loudness. Topics : Vibration Sense (in General); Subjective Assessment (Magnitude Estimation, Magnitude Production); Combined Stress (Vibration and Noise). D. E. Johnston, R. H. Klein and R. H. Hoh 1976 NASA-CR-2677. Manual and automatic flight control during severe turbulence penetration. (110 pages, 55 figures, 6 tables, 17 references) Authors’ Abstract. An analytical and experimental investigation of possible contributing factors in jet aircraft turbulence upsets was conducted. Major contributing factors identified