Piezo-composite membranes have advantages over motorized flapping where frequencies are high and certain coupling between bending and twisting is useful to generate lift and forward flight. We draw examples of fruit fly and bumble bee. Wings with Piezo ceramic PZT coating are realized. The passive mechanical response of the wing is characterized experimentally and validated using finite element simulation. Piezoelectric actuation with uniform electrode coating is characterized and optimal frequencies for flapping are identified. The experimental data are used in an empirical model and advanced ratio for a flapping insect like condition for various angular orientations is estimated.
Paper reports a resistive type humidity sensing studies
of ZnO-SnO2 nanocomposite powder pellets prepared
through solid-state reaction route. When exposed to
humidity, resistance of pellets decreases with increase
in relative humidity from 10 to 90%. Sensing element
with 25 weight% of SnO2 in ZnO shows best results
with maximum sensitivity of 1.25 MΩ/%RH in 10-
90% relative humidity range. This sensing element
manifests smallest crystallite size of 60 nm as
measured from XRD and lowest grain size of 92 nm
calculated from SEM micrograph. This sensing
element manifests low hysteresis, less effect of ageing
and good reproducibility. The response and recovery
time of sensing element SZ-25 is found to be 92 and
480 seconds respectively.