Publications

In this paper we introduce a model of cooperation between High School-University-Industry sustained by activities and results obtained in "Cypress - National Instruments Club" started at "Transilvania" University of Brasov - Romania. This strategic collaboration between High School-University-Industry was become necessary because technology is evolving at a rate that is quickly outpacing traditional engineering teaching methods. New methods such as hands-on learning labs, industry-centric curriculum, permanent updating of facilities, and using new adaptive learning software are being adopted. "Transilvania" University is targeting education at the industries of the future rather than industries of the past and for this reason we must apply the same strategies inside the high school in order to well prepare the children's, future students and the new engineers.

We investigate the photoluminescence properties of structures comprising of Si1-xGex nanoparticles (NPs) within SiO2, GeO2, TiO2 and Ta2O5 oxide matrices. Of the investigated structures, it was observed that the structures with GeO2 and TiO2 matrices provide increased spectral response (at similar to 907 and 844 nm respectively) and increased PL intensity. The improved PL characteristic have been attributed to increased diffusion barrier against oxygen which otherwise would result in formation of unwanted oxide at the film-oxide interface, thereby deteriorating the optical properties.

Composites of BaTiO3 (BT) and doped-PZT (d-PZT) micro-particles randomly dispersed in a PDMS matrix were prepared by a molding process. The morpho-structural characterization, performed by SEM and XRD, showed ceramic micro-grains of cubic BT and orthorhombic d-PZT, randomly dispersed in the PDMS matrix. Polarization (P) as a function of the applied field (E) was measured for composite samples, as well as for polymer samples. Hysteresis loops typical for a dielectric material were obtained, but also atypical ones, especially for higher fraction of polymer in composite, lower fields and shorter measuring periods, as a result of the dielectric relaxation in polymer and the presence of interfacial polarization charges at the contact between polymer and ferroelectric. All these composites show very low polarizations (less than 0.2 mu C/cm(2) and 0.05 mu C/cm(2) the maximum and remnant polarization, respectively), caused by the very low dielectric constant of the polymer (less than 10), which drastically reduces, up to 100 times, the electric field effectively applied to the ferroelectric. Weak pyroelectric response was recorded on BT/PDMS, but a typical behavior of a pyroelectric detector was observed. A figure of merit of the material which exceeds 10(-4) m(2) /C was estimated.

In this study, polystyrene composites (PS-GO(f)) with variable concentration (0.5; 1; 2; 3; 4; and 5 wt%) of GO(f) were obtained through the in-situ polymerisation of the styrene in the presence of benzoyl peroxide and graphene oxide(GO) functionalized with 3-(methacryloyloxy)-propyltrimethoxysilane(gamma-MPTS). For determining the morphological and structural particularities of polymeric composites transmission electron microscopy (TEM) measurements were performed. The influence of functionalized GO on thermal and combustion properties of polystyrene (PS)-based composite materials was determined through several methods: Thermogravimetry (TGA); derived thermogravimetry (DTG); microscale combustion calorimetry analysis (MCC); and chemical kinetic studies through TGA and MCC determinations at similar heating rates.

Deposition of Ge nanoparticles in Si3N4 films by heating Si and quartz substrates at 500 degrees C were obtained using co-sputtering Ge, and Si3N4. Their structure and photo-electrical behaviour were investigated by transmission electron microscopy, current - voltage and spectral photo-current investigations, respectively. The spectral photoresponse were correlated with microscopy results. Depending on the measuring temperature, the current under illumination increases with about five orders of magnitude compared with the dark one. The photo-current spectra measured in photovoltaic regime and at -1 V show a single cut-off wavelength in near infrared domain at about 1362 nm.

The memory properties of a trilayer structure of ZrO2/Ge-ZrO2/ZrO2/Si-p were investigated. The trilayer was prepared by magnetron sputtering deposition followed by a rapid thermal annealing process for obtaining Ge nanocrystals embedded in ZrO2 matrix. The X-ray diffraction patterns obtained on annealed structures show that both trilayer structures are cristallized, with narrow diffraction peaks. Ge as a separated phase is not evidenced in the diffractograms, instead is possible that Ge atoms enters in ZrO2 lattice structure and form a compound of ZrO3GeO8 crystallized in the tetragonal phase. In the case of ZrO2 control structure, the diffractograms show that the ZrO2 layer is crystallized in tetragonal phase. The memory properties are evidenced by C-V characteristics with counterclockwise hysteresis loop and a memory window of Delta V=1.1V for the structure annealed at 570 degrees C and Delta V=0.8 V for the structure annealed at 650 degrees C. The influence of the interface SiO2 layer on the frequency dependence of capacitance was evidenced by C-f characteristics.

The paper presents the research results in the field of TiNiCu shape memory alloys processed by powder metallurgy techniques. The powders mixtures used to synthesize Ti50Ni30Cu20 alloys were obtained by blended constitutive elemental powders or by mechanical alloying of powder mixtures for 10 and 20 hours, respectively. Finally, a subsequent annealing process was carried out, followed by a rapid cooling in ice water. All experiments were performed under 99.9% argon atmosphere. At room temperature, the obtained materials contained monoclinic and orthorhombic martensite type. The structural and thermal investigation of these materials were discussed in view of the potential development of actuators.

Context: The work shows the alignment of virtual environment to the needs of the industrial revolution of level 4. Purpose or Goal: The work insists on the qualities that remote experiment offers for the global engineer creation and on the skills for hiring and rapid adaptation to the industry needs. Approach: In the university environment the remote experiment plays a decisive role in facilitating e-learning development for specialties that cannot exist without an experimental-applying part. Remote experiment must to satisfy both the needs of evolution in education and those from the industry (i.e. globalization, digitalization, socio-economic world). It is noted the emergence of new skills namely: "Cognitive flexibility" and "Emotional intelligence". After us, the most important trend, derived from the application of remote experiment and its use is "acceptance of failure". Until recently, the failure was penalized with bad marks. Acceptance is defined as a succession of failures by whose gradual removal, the amount of accumulated knowledge increases. It was concluded that failure is an important part of the road to innovation and creativity. Actual or Anticipated Outcomes: Technology progresses exponentially and the society linear. Over time, it can create a gap between technology and society. It was found from practice that the remote experiment is much more connected to the needs of industry than classical laboratories. Conclusions/Recommendations: Remote experiments can create skills and competencies faster than those achieved through classical learning systems for immediate necessity in industry.

This paper presents the study of the development of complex organic materials deposited by the Langmuir Blodgett technique. We have synthetized Langmuir Blodgett multilayers for the recognition of toxic chemicals in the air and / or ultraviolet radiation. The sensitive materials are based on multilayers of stearic acid metal salts combined with nanocarbon and metalloporphyrin structures. We prepared and obtained by the Langmuir Blodgett method films with nano-metric thicknesses combined in different concentrations of metal salts of fatty acids, Nano carbon structures and metalloporphyrins. Further we have characterized and tested the materials obtained for the sensitivity and selectivity of multilayers under the influence of various toxic gases and / or ultraviolet radiation obtaining high results in the field of sensors.