Romeo Ciobanu

LTCC-based ceramic microsystems with integrated fluidic elements and sensors

In this contribution the design and fabrication of ceramic microsystems with integrated different microfluidic elements and sensors will be presented. Ceramic microsystems are based on unconventional application of low-temperature co-fired ceramic technology and materials. This unconventional application is related to three-dimensional ceramic structures, such as cantilevers, ledges, bridges, diaphragms, valleys, channels, holes and cavities, valves, mixers, diffusors, distributors, collectors, flow limiters, sensors, and actuators.

Dielectric and electromagnetic behavior of conductive nanocomposites polymers: PP/MWCNT investigations for EMI applications

The paper highlights the most important dielectric features for some nanocomposites polymer matrix based on polypropylene (PP) with insertion of carbon nanotubes multi-walled (MWCNTs). The dielectric characteristics analyzed are the real permittivity and dielectric losses of the sample based on PP with 5% insertion of MWCNTs. The measurements are made in a range of frequency between 1 MHz to 3 GHz. The composite form was also analyzed through computer modeling and simulation and electromagnetic properties for EMC shielding applications are also considered. PP/MWCNTs composite with shielding effectiveness of 15-20 dB was investigated through modeling and simulation at about 5% MWCNTs filling. Shielding mechanism was estimated by calculating the total shielding effectiveness (SE) into absorption and reflection loss. PP/MWCNTs composite indicates a shielding mostly by absorption mechanism; therefore it also can be used in other microwave applications or like a radar absorbing material. The effect of MWCNTs affects the electrical conductivity of the nanocomposite. The proposed material shows some interesting electromagnetic compatibility (EMC) properties and promises better performance using different amounts of MWCNTs.

Identification of pilot nodes for secondary voltage control using K-means clustering algorithm

The voltage control represents one of the most important qualitative factors, and it is addressed to the secondary power system control level. The performance of secondary voltage control depends strongly on the selection of pilot nodes. This paper proposes the use of K-means clustering algorithm order to the identification of pilot nodes for Secondary Voltage Control (SVC) in the power grids. In the first phase, the algorithm is based on the zoning of power grid into coherent and completely connected clusters (control areas). In the second phase, a node will be selected as pilot node for each control area. The pilot node must satisfy a minimum criterion based on the sum of electrical distances between it and all the others nodes. The obtained results were compared with other classical methods using a test system. The conclusion was that the algorithm can be used successfully in the optimal zoning of power grids and the identification of pilot nodes for SVC.

Patterns discovery of load curves characteristics using clustering based data mining

The paper presents a comprehensive approach using clustering based data mining for load curves characterization in real distribution networks. The load curves characterized by their main indicators is made using information provided by Smart Meters. The proposed method was tested using a real database with 60 rural substations. The results demonstrate the ability of the methodology to be efficiently used by distribution operators in patterns discovery of the load curves characteristics with the help of which an energy losses estimation in transformers from the distribution substations could be made.

Influence of hybrid energy systems on micro-grids control

The paper aims to realize the micro-grid control in presence of distributed generation (DG) sources and the automatic voltage regulators (AVR). The provided analysis had into account highlighting the influence of the hybrid energy systems with consideration of the automatic voltage regulators on the power losses and the voltage level into micro-grids. The obtained results with the highest power/energy saving were obtained when there was a strong correlation between the DG sources and automatic voltage regulators.

Screen-printed Pb(Mg, Nb)O 3 -PbTiO 3 thick tilms on ceramic substrates for sensor applications

In this work the screen-printed piezoelectric 0.65Pb(Mg_1/3Nb_2/3)O₃-0.35PbTiO₃ thick films were prepared on metalized low-temperature co-fired ceramic substrates. Such substrates are interesting for micro-electro mechanical systems, for example for piezoelectric sensors and actuators. The prepared thick films exhibit the piezoelectric coefficient d₃₃ equal to 120 pC/N.

Sensors in LTCC-technology with embedded microfluidic features, for medical applications

The lab-on-chip testing units based on microfluidics technology are booming nowadays, due to robustness, simplicity of use and reliability. Multilayer ceramics, functionalized with nano-scaled sensing materials, and further integrated within microfluidic test elements, are of great challenge and represent the purpose of the paper. The LTCC technology versatility allows the 3D integration of electrochemical sensors with microfluidic features, and further with advanced signal processing and wireless communication.

A LabVIEW based data acquisition system for temperature measurement of animal liver tissue with different procentage of magnetic insertions in microwave frequency range

For temperature measurement was used a thermocouple J. The sensor is connected to a special acquisition board supplied by National Instruments - NI 6210. Virtual instrument panel allows simultaneous monitoring of temperature variations, establishing a minimum and a maximum threshold and signaling the exceeded temperature.

Dielectric spectroscopy of biological tissues with targeted Fe 2 O 3 drug delivery systems in support of RF/MW-hyperthermal control

The study deals with the investigation of the dielectric behavior of liver tissue with different percentage of magnetite nano-insertions at temperature and frequency variation by employing the Broadband Dielectric Spectroscopy. The results are needed in order to develop targeted drug delivery system associated with RF/MW-hyperthermal control for hepatic tumors. Crucial to the development of this technique is the accurate knowledge of the dielectric properties of biological tissues for an accurate chemo-hyperthermal effect design under radio-frequency or microwave exposure.

Nano-structured electromagnetically-active adhesives for innovative assembling-disassembling technologies

The development of efficient and reversible bonding technologies offer cost reduction, resistance to applied load, easy and rapid dismantling and smart recycling processes. Different concentrations of electromagnetically-active fillers were embedded in the thermoplastic matrix of provisional hot-melt adhesives and tested to assess their thermal behaviour under broadband electromagnetic fields. A power radiofrequency system was used to study the joining features vs. exposure time for different compositions and frequencies. Positive conclusions of tests were emphasized on the way of prototyping the innovative joining technology for automotive industry.