Skin penetration efficacy by a silicon microneedle array (13x13 mm2) for drug delivery, each consisting of 100 microneedles, 200 µm high and fabricated by DRIE process, was investigated. To evaluate the penetration efficacy through the mechanically and electrically resistant upper skin layer of stratum corneum, the electrical skin impedance change with applied force was measured by using Au-coated Si microneedle array as working electrode. Results were analysed by Cole- Cole impedance plot and equivalent electrical circuit elements were determined. By implementation of impact assisted penetration method of microneedle array a significant impedance reduction was obtained, which is a strong evidence of successful skin penetration. Analyses of Si microneedle mechanical properties revealed that by proper use a safety margin )60 can be achieved.
COBISS.SI-ID: 11053652
Development, numerical optimization, and fabrication of piezoelectric microcylinder pumps are presented. Innovative design is based on a centrally placed inlet port which leads directly into the center of the pumping chamber. Unique features of microcylinder pumps were developed through virtual device prototyping, using an advanced 3D fully coupled electro-mechanical-fluidic (EMF) model built in COMSOL Multiphysics 4.3b simulation environment. To validate developed simulation model, microcylinder pumps with various pumping chamber diameters were fabricated employing soft lithography process. Optimized micropump prototype exhibits flow rates up to 2.3 ml min-1/8 ml min-1, backpressures up to 520 mbar/55 mbar, and suction pressures down to -480 mbar/-85 mbar for DI water and air, respectively. Furthermore, it features self-priming ability and high level of bubble tolerance.
COBISS.SI-ID: 11081812
Impact of the shapes of driving signals on micropump operation is investigated by numerical simulations and by experimental verification on a strip-type microthrottle pump. Numerical simulation is based on an advanced, fully-coupled electro, fluid and solid-mechanics model, enabling detailed analysis of device operation. Flowrate performance and cavitation risk were evaluated by analyzing pressure response in critical points near and under the membrane and by analyzing simulated flowrate response on various excitation waveforms. Sinusoidal excitation provides lower flowrate compared to square-wave excitation (typically 33 % lower) but with significantly smaller risk of cavitation. Sawtooth excitation was found the most inappropriate waveform, providing lowest flowrate performance at high cavitation probability.
COBISS.SI-ID: 10803796
In a paper it is demonstrated that capacitors with single-printed dielectric layers are without shorts if the layer is completely polymerized. To demonstrate this, the electrical functionality of capacitors with single-printed dielectric layers was studied in terms of intrinsic properties of the ultraviolet (UV) curable dielectric layer, which were varied according to the curing energy. The chemical structure of the cured layer was analyzed with infrared spectroscopy to obtain the appearance of polymerizable groups and crosslinks within the polymer structure. This research confirms that a completely polymerized layer forms a barrier to leakage and helps to prevent the formation of conductive paths between electrodes.
COBISS.SI-ID: 5689370
An investigation of a device for measuring vault characteristics using a miniature Micro-Electro-Mechanical (MEMS) type accelerometer(s) attached onto the springboard is presented. Measured signals were filtered using a Butterworth filter of fourth order with a cut off frequency of 250 Hz. The obtained parameters are evaluated by comparing them to the data obtained by a reference high precision laser. The measurement technique is capable of determining several relevant parameters with an accuracy of less than 5.3 % except for maximal positive velocity for which an error is up to 15.3 %. Analysis of 43 jumps of single gymnast proved the reliability of the extracted parameters.
COBISS.SI-ID: 4765617