Deceleration Tests Research Articles

A new procedure to determine external power output during handrim wheelchair propulsion on a roller ergometer: a reliability study.

This study presents a mathematical model by which power output (PO) delivered to the rear wheel during handrim wheelchair propulsion on a roller ergometer can be determined for individual wheelchair-user combinations. PO is calculated from the torque applied to the wheel and its angular velocity. The torque applied is a function of one total internal torque of the wheelchair-ergometer system, the rotational moment of inertia of the rear wheel, the one of the roller and its angular acceleration. The total internal torque reflects all internal friction forces and is determined with a deceleration test. To assess the reliability of this approach, 11 able-bodied subjects underwent progressively increasing exercise tests on two different occasions. PO values ranged from 12 to 63 W and were highly reliable (r2 > 0.95). Peak physiological responses were never different from test 1 and 2 (repeated measures ANOVA; p: N.S.) and correlations were 0.90, 0.72, 0.88, 0.82, 0.70 and 0.85 for PO, oxygen uptake (VO2), heart rate, minute ventilation, carbon dioxide production and blood lactate concentration, respectively. After an initial increase, gross mechanical efficiency dropped at higher velocities, with values ranging from 4.64 to 11.26%. In conclusion, the roller ergometer, the mathematical model to determine PO and the protocol used seem to be adequate to exercise test people in a handrim wheelchair. It is feasible to apply the theoretical procedure to other roller ergometers which would allow for comparisons of exercise intensities and protocols between different devices used in exercise physiology and rehabilitation.

Diagnosis of Chronic Injury to the Anterior Cruciate Ligament

The diagnosis of chronic injury to the anterior cruciate ligament is proved by accurate interpretation of its visualization at arthroscopy, arthrotomy, or necropsy. Chronic injury is suspected if the history indicates an original trauma with an episode of swelling or hemarthrosis followed by a temporary period of disability and a subsequent report of repeated limb collapse. Positive functional tests such as the crossover, leaning hop, and deceleration tests support the diagnosis, as does the radiographic presence of a Segond's fracture or a notch in the lateral femoral condyle. The diagnosis is confirmed by the combined presence of positive laxity and instability tests. The laxity tests employed are the drawer tests with the knee in 15 and 90 degrees of flexion and the flexion-rotation drawer test. In diagnosing chronic injury to the anterior cruciate ligament, I place most reliance on the presence of positive pivot shift tests that demonstrate instability. Occasionally, a direct radiograph of the subluxated knee joint or double contrast arthrography is employed to confirm the diagnosis.

Contribution to accurate measurement of aerodynamic drag on a moving vehicle from coast-down tests and determination of actual rolling resistance

A realistic measure of C D is obtained from deceleration tests in light cross-wind on a track having slight gradient by considering velocities relative to the track and to the wind. Combination of this measure with C D obtained in wind-tunnl tests and with a value for the base rolling resistance determined at low speed on a gentle incline permits determination of a realistic value for the rolling resistance for different types of tyre and road surface. It is possible to establish energy balances and correlations between wind-tunnel, track and roller bench measurements.

Interior/Exterior Noise Levels of Over-the-Road Trucks

Interior/exterior measurements were made on 15 trucks covering many makes, models, and drive-train combinations to provide an information base concerning vehicle interior noise levels for rulemaking by the Bureau of Motor Carrier Safety, Department of Transportation. Measurements were made 6 in. from the left and right ears of the drivers under various vehicle operational modes with windows open and closed. Stationary tests included: (a) low idle, (b) acceleration from low idle to maximum governed rpm with wide open throttle while in neutral gear; and (c) high idle. In addition to the acceleration and deceleration tests specified by SAE J366 (Exterior Sound Level for Heavy Trucks and Busses), an additional moving test was performed to simulate a truck starting up in city traffic. In order to study the effect of total truck noise on the community, simultaneous exterior measurements were made with an array of six microphones. The data obtained, as well as the test procedure and measurement techniques utilized, will be discussed.

INFLUENCE UPON NYSTAGMUS OF THE THREE DIFFERENT STATES OF EYE-OPENING IN A BRIGHT ROOM, EYE-OPENING IN A DARK ROOM AND EYE-CLOSURE

We have reported that closure of eyes has an activity effect upon caloric nystagmus and an inhibitory effect upon the nystagmus during the rotation. The purpose of the present study is to elucidate the influence upon nystagmus of the three different states of eye-opening in a bright room, eye-opening in a dark room and eye-closure, with the help of E.E.G. findings in the Parieto-Occipital lead. Following three experiments were conducted on an assumption that one is optically stimulated and visually alert in the state of eye-opening in a bright room, visually alert but not optically stimulated in the state of eye-opening in a dark room and neither optically stimulated nor visually alert in the state of eye-closure. Experiment I.; In the above-mentiond three different states, Wtist's pendular test was performed with 10 normal persons using the damped pendular rotation chair worked by a spring, and the eye speed of nystagmus in both rapid and slow phases was recorded during the rotation. Experiment 2. ; Kobrak's deceleration test was performed with 10 normal persons using the same chair as used in Experiment I in the three different states. Eye speeds of nystagumus during the rota- tion and of postrotatory nystagmus were recorded. Experiment 3.; Eye speed of caloric nystagmus evoked with 30°C, 20cc water in 6 normal persons was recorded in the three different states.Result1) Eye speed of nystagmus during the rotation invariably decreased in the following order; in the state of eye-opening in a bright room, eye-opening in a dark room and eye-closure.2) Eye speeds of postrotatory nystagmus and of caloric nystagmus were invariably larger in the state of eye-opening in a dark room than in the state of eye-opening in a bright room, and they were usually smaller in the state of eye-closure than in the state of eye-opening in a dark room.3) As the result of analytical study of the three different states, an assumption was made that both optic stimulation and visual alertness existed in the state of eye-opening in a bright room, the former being deprived in the state of eye-opening in a dark room and that neither of them operated in the state of eye-closure.4) Based on the assumption mentioned in the result (3), an inference was drawn that deprivation of optic stimulation exerted an activating effect upon postrotatory nystagmus and caloric nystagmus and an inhibitory effect upon the nystagmus during the rotation. Deprivation of visual alertness on the other hand had an inhibitory effect upon all three kinds of nystagmus examined.

EFFECTS OF ACCELERATION ON THE HUMAN BODY AND RESPONSE TO PHYSIOLOGICAL PERMISSIBLE LIMITS

Acceleration and deceleration tests are performed on 100 subjects who are free from possiple motion sickness in an attempt to define physiological permissible limits on a comfort index basis. The results obtained are as follows : 1) Through a mathematical approach it is disclosed that physiologically 0.19 g for acceleration, ration are found to be limits. 2) The passenger's sitting position is the best, and in standing position with the face in running direction is the worst on comfortable index. cted to chronological changes. parative changes before during and after the tests. 5) None have developed car sickness during and after the tests, 36 subjects have complained of fatigue.

Instrument panel impacts and snubbing deceleration tests.

Instrument panel impacts and snubbing deceleration tests.

An application of deceleration test methods to the determination of induction-motor performance

RETARDATION tests have been used by industry for a long time. They have found their main applications in the determination of certain machine losses, usually friction and windage and core loss. The machines to which these methods have been applied have ordinarily had large mass and low rotational losses with the result that a considerable time would elapse between the time the power was shut off and the time the machine would come to rest. By proper selection of equipment and analysis the same methods may be applied to much smaller machines having relatively short stopping periods. In the present instance the methods have been applied to two double squirrel-cage induction motors, one a 7 1/2-horsepower 6-pole machine, and the other a 5-horsepower 4-pole machine. In each case the inertia was increased to about twice that of the motor alone by the use of a small flywheel. A similar analysis has been applied to acceleration tests on these two motors in which the motors were started at reduced voltage. By combining the acceleration tests with the decleration tests the speed-torque curves of the motors have been obtained. It is hoped that the discussion of the difficulties and the results of these tests will help to indicate the value and limitations of the methods as applied to similar determinations in this and other fields.

An Application of Deceleration Test Methods to the Determination of Induction-Motor Performance

RETARDATION tests have been used by industry for a long time. They have found their main applications in the determination of certain machine losses, usually friction and windage and core loss. The machines to which these methods have been applied have ordinarily had large mass and low rotational losses with the result that a considerable time would elapse between the time the power was shut off and the time the machine would come to rest. By proper selection of equipment and analysis the same methods may be applied to much smaller machines having relatively short stopping periods. In the present instance the methods have been applied to two double squirrel-cage induction motors, one a 7 1/2-horsepower 6-pole machine, and the other a 5-horsepower 4-pole machine. In each case the inertia was increased to about twice that of the motor alone by the use of a small flywheel. A similar analysis has been applied to acceleration tests on these two motors in which the motors were started at reduced voltage. By combining the acceleration tests with the decleration tests the speed-torque curves of the motors have been obtained. It is hoped that the discussion of the difficulties and the results of these tests will help to indicate the value and limitations of the methods as applied to similar determinations in this and other fields.