Rate Of Force Application Research Articles

A NOTE ON THE SENSITIVITY OF FINGERS, TONGUE AND JAWS AS MECHANICAL TESTING INSTRUMENTS

ABSTRACTDeformation of a specimen between the fingers or in the mouth usually results in a significant deformation of the contacting tissues. This implies that the mechanical response is related to both deformations or, in other words, to the mechanical resistance of the combined systems. Since the latter form an in‐series configuration, the combined mechanical resistance (Mc) is given by:where M1 and Mx are the resistance of the sensory testing system and the test specimen, respectively. Thus, Mc can be a function of the geometry and the rate of force application. The equation provides a simple explanation as to why there are differences in the sensing range between the fingers and the jaws and why the human senses are practically insensitive to hardness beyond certain levels. The model indicates that the sensitivity decreases rather rapidly after the ratio Mx/M1 becomes greater than about 0.05, but leaves unanswered the question whether, or to what extent, we can compensate for the loss of sensitivity by additional information or modification of the testing procedure.

Psychophysical threshold level of periodontal mechanoreceptors in man

It is known that neurophysiological and psychophysical threshold levels (RL) for mechanoreceptors are reached at the same stimulus amplitude. Therefore, the function of periodontal mechanoreceptors in man was investigated by psychophysical methods. The effects of varying the quality of mechanical stimuli on the RL was examined. Characteristics known for mechanoreceptors elsewhere in the body, also applied to periodontal mechanoreceptors. The RL was subject to fluctuations, fatigue and rate of force application. The latter relationship was semi-logarithmic and was similar to the relationship between tooth intrusion and rate of force application, tending to indicate that the RL characteristics of mechanoreceptors are set by their binding with the environing visco-elastic tissues. No uniform directional sensitivity for axial movements could be demonstrated.

A TECHNIQUE FOR ESTABLISHING INSTRUMENTAL CONDITIONS FOR MEASURING FOOD FIRMNESS TO SIMULATE CONSUMER EVALUATIONS*

Abstract. A method is described for measuring the force and the rate at which it is applied to fruits and vegetables by the consumer's hands in judging firmness. Halves of the product were mounted on a force transducer, squeezed and the forces recorded. Preliminary results from an untrained panel indicated that the rates and maximum forces used by males and females are different and depend on the firmness of the product. The data also suggest that the rate of force application in sensory testing is significantly greater than that customarily used in instrumental tests.Limitations of the technique and its potential usefulness in establishing more rational conditions for objective firmness tests are discussed.

EVALUATION OF SOME TEXTURAL PROPERTIES OF FOODS WITH THE INSTRON UNIVERSAL TESTING MACHINE

Abstract. Analysis of published chewing force patterns indicates that the ‘first bite’ involves an approximately linear application of force. The Instron Universal Testing Machine also offers a linear pattern of force application making it possible to obtain information about textural properties identified during the ‘first bite’ from force‐compression tests. However, the data obtained in such tests are influenced not only by the applied force but also by the rate at which it is applied. Both variables must be taken into account when analysing the data, since the applied force in chewing and also the rate of force application depend on the textural characteristics of the food being evaluated. Based on a correlation of sensory responses with instrumental force‐compression‐rate of force application data, a procedure is described for establishing the mechanical force conditions that should be used in Instron tests so that they simulate those associated with the sensory evaluation.

Sensory mechanisms in mammalian teeth and their supporting structures.

Sensory mechanisms in mammalian teeth and their supporting structures.

Rate of force application in a simple reaction time test.

Rate of force application in a simple reaction time test.