1,720,989 research outputs found
Physiological Cybernetics:Model of Osmolality and Volemia
No full textThe models of osmolarity and volemia are proposed in this paper. These two different models, characterized by a different time scale, represent a typical example of embedded physiological feedback control in medicine. Extensive simulation tests have been performed, showing that the models agree with the findings published in the literature of endocrine physiology and with medical practice. As a relevant example of application of the models, the diabetes insipidus pathology was considered. In the case of center insipidus diabetes, it is possible to predict effects of a therapy, giving out synthetic ADH for restoring homeostatic conditions. This model may be a helping tool in the study and development of micro-infusors with sensor and controllers embedded able to release a controlled drug quantity, accorded to the patient and optimized for avoiding hyper or ipo-concentrations of plasma ADH hormone
Actuative properties of polyaniline fibers under electrochemical stimulation
No full textIn the last period, the interest in the development of devices that simulate the properties of the ‘par excellence’ biological actuator, the human muscle, is considerably grown. The recent advances in the field of conducting polymers open new interesting prospects in this direction: by this point of view polyaniline (PANi), since it is easily produced in fiber form, represents an interesting material. In this paper, we illustrate the development of a linear actuator prototype that makes use of PANi fibers. All fabrication steps (fiber extrusion, solid polymer electrolyte preparation, compound realization) and experimental set-up are described. Quantitative measurements of isotonic length changes and isometric stress generation during electrochemical stimulation are performed. An overall assessment of the PANi fibers actuative properties in wet and dry conditions is reported and possible future developments are propose
Electromechanical characterization of dielectric elastomer planar actuators: comparative evaluation of different electrode materials and different counterelectrodes
No full text
Performances and working capacity of a Ppy conducting polymer linear actuator
No full textThis paper reports a performance analysis of a conducting polymer film actuator made of polypyrrole (PPy). Electrochemomechanical characterizations of the active displacement and the developed force of a PPy free-standing film at different loading conditions are performed. Two driving signals are used: the former, a cyclic voltammetry at 1 mV/s between ± 1 V, is used to carry out an accurate on-line analysis of the film displacement; the latter, a current square wave between 0.02 and 0.1 Hz, is helpful for evaluating the effectiveness of the actuator in terms both of actuation strain and of developed force. The experimental results indicate that 1 % displacement, 3 MPa force and working density of 73 kJ/m3 are achievable goals for a conducting polymer linear actuator, which are interesting results if compared with the limiting specifications of skeletal muscle. Additionally, two different approaches to the electrochemomechanical modeling of the conducting polymerfluid electrolyte system are illustrated, together with a discussion about foreseen improvements in the implementation of actuating structures
From sensitive textile to distributed wearable sensors
No full textOur previous work has shown that elastic textiles covered with an epitaxial layer of conducting polymer show piezoresistive properties. They can be used to fabricate sensorized garments such as gloves, leotards, socks and seat covers as man-machine interfaces. A purposely designed screen printing process has been implemented to realize sensors/tracks patterns. Polypyrrole/lycra fabrics were prepared using the method developed by Milliken Co. (Spartanburg, USA). The epitaxial deposition is obtained controlling the concentrations of monomer and the temperature of the reaction medium. Investigation on mechanoelectric transduction properties (static and dynamic) of the fabrics, calibration of wearable sensing devices and ongoing R&D efforts in multimedia, sport and rehabilitation fields are reported
- …
