Electro-thermo-mechanical analysis of actuator structure made of functionally graded material.

The paper deals with a new approach in analyzing of the actuator systems made of Functionally Graded Materials (FGM) using our new beam finite elements. Weak coupled electro-thermomechanical analysis and spatial continuous variation of material properties are considered for chosen actuator structure. This electrically driven actuator is simple-shaped due to properly chosen variation of material properties to ensure functionality of the actuator at material and physical level instead of the geometric shape level. The solution results will be compared with those obtained by using solid elements of a FEM commercial program

Actuator structure analysis using new electro-thermo-mechanical finite element for functionally graded materials.

Proposed paper deals with electro-thermo-mechanical analysis of chosen actuator structure made od FGM using new finite element derived specially for this purpose. Rectangular cross-section of individual beams that form the von Mises structure with variation of material properties in longitudinal and lateral direction will be considered. Actuator action, electric voltage and temperature peak and also mechanical stress of the structure will be evaluated. Results from the analysis calculated using our new FGM beam finite elements will be compared to results from conventional FEM analysis where standard finite elements will be used

Forced vibration of the aluminum beam using a piezoelectric actuator - experiment and finite element analysis.

This paper deals with the forced vibration of the aluminum beam using a piezoelectric actuator. Cantilever beam was excited by thin piezoelectric film placed near the fix support. The oscillation of the free end of the beam was measured using a laser displacement sensor. The beam's eigenfrequency and damping ratio for the first bending vibration mode was determined experimentally. The beam's deflection when the beam was excited by a piezoelectric actuator was also determined experimentally. The actuator was controlled by a signal generator and high-performance power supply and linear amplifier module for driving piezoelectric actuators. Data from experimental measurements were used to validate the finite element model of the beam with piezoelectric actuator. Results from experimental measurements and numerical simulations were compared

α-Lipoic Acid Vaginal Administration Contrasts Inflammation and Preterm Delivery in Rats

alpha-Lipoic acid (ALA) is a safe natural molecule involved in the immunomodulation of many physiological processes. Orally administered ALA has been reported to treat several inflammatory pathologies and support pregnancy. Our study aimed at testing ALA vaginal administration in female Wistar rats evaluating its tissue distribution (experiment I), impact on implantation process (experiment II), and effectiveness in contrasting induced preterm birth (experiment III). In experiment I, rats were intravaginally treated with 50 mg/kg or 500 mg/kg ALA, or with a physiologic solution, for 4 days. alpha-Lipoic acid distribution in uterus and cervical tissues was evaluated by immunohistochemical analyses. In experiment II, rats received intravaginally the above treatments for 5 days, then they were mated and, if pregnant, included in the experiment to evaluate both implantation rate and the content of implantation mediators in uterus tissues. In experiment III, pregnant rats were pretreated with placebo or with vaginal ALA for 4 days and then induced to delivery with mifepristone plus PGE2 on the 19th day of pregnancy. The delivery time was recorded, and the messenger RNA (mRNA) levels of pro-inflammatory cytokines were detected in the uterine tissues by real-time polymerase chain reaction. Immunohistochemistry was also performed. Results showed that vaginal ALA was well absorbed and distributed. The treatment did not affect the implantation process and was able to significantly revert mifepristone plus prostaglandin E2 effects, delaying the timing of delivery and significantly decreasing mRNA synthesis and release of pro-inflammatory cytokines. We provide for the first time new information on vaginal ALA use, even during pregnancy, opening a perspective for further studies