Shema de realizare a proiectului 19 15 01 01 - Anul 2019 - Etapa I


Faza nr. 1

Responsabil: Dr. C. Ticos

Termen de predare: 14.03.2019

Titlu: "Tehnica particle image velocimetry (PIV) pentru studiul colectiv al dinamicii microparticulelor iradiate cu electroni"

Abstract: The PIV (Particle Image velocimetry) technique is used to study the dyanmics of dusty plasmas.The kinetic effects on the dust particles are studied experimentally in a plasma crystal locally irradiated by a narrow pulsed electron beam with energy 13 keV and peak current 4 mA. We observe in the top layer of the plasma crystal the formation of a stable dust flow along the irradiation direction in the first ≈200 ms of the interaction. The dust flow eventually becomes perturbed later in time, with the dust particles having
chaotic trajectories as they are still drifting in the beam direction. The speed of the dust flow is mapped in a horizontal plane using PIV. The kinetic energy of the flow and its vorticity are deduced based on the speed vectors provided by PIV. A maximum energy transfer factor ≈0.048 from the electron beam is inferred considering the peak kinetic energy (≈625 eV) of the dust flow. Vortices and tripolar vortices are observed when the dust flow becomes perturbed.

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Faza nr. 2

Responsabil: Dr. A. Stancalie

Termen de predare: 14.03.2019

Titlu: "Caracterizarea fibrelor optice folosite in sisteme de laseri pe fibra utilizand reflectometru optic in frecventa si analizare de spectru. Realizarea de iradieri cu radiatie ionizanta a fibrelor si caracterizarea parametrilor optici (RIA)"

Abstract: The main goal of this project was to study the parameters of a fiber laser (ring laser configuration), in terms of laser stability output over time and laser power output, by using both irradiated and non-irradiated silica-based Erbium Doped Fibers (EDFs) in a comparative manner. As a secondary task, we aim to obtain a random laser configuration by using a gamma irradiated optical fiber.
In the present project, we studied extensively the ionizing radiation effects on multiple optical fiber configurations. Among LPG and FBG sensors, two types of EDF, 5 meters long were irradiated with doses starting from 200 Gy up to 1kGy. The gamma-ray irradiation was run at a 60Co IFIN-HH irradiator with a dose rate of 0.2 si 0.3 kGy/h. Secondly, the gamma-ray irradiation was run at a 60Co GC-5000 (BRIT, India) irradiator having a chamber volume of 5,000 cm3. The dose rate was 5.7 kGy/h (±1.8 %). The working plan that was carried had several steps. Before introducing the fibers in the fiber-ring configuration, they were carefully analysed with an optical spectrum analyser as well with a optical frequency domain reflectometer. Radiation induced effects were found to be linear with accumulated dose but different between the two types of optical fibers utilized. The first EDF fiber was M-12(980/125), which is a highly erbium doped fiber with a high conversion efficiency and designed for small package size C-band amplifiers. The second studied EDF was the type I-25(980/128), and also suitable for C amplifiers with an optimized core composition for high-channel-count DWDM systems´ EDFAs. For these fibers, the peak core absorption were between 16 to 20 dB/m at 1531nm. As a second part of this study, each EDF fiber, was introduced into a laser ring configuration to serve as active medium within the cavity. The setup consisted of a 980 nm EDFA pump, a WDM coupler, the irradiated EDF and a fiber Bragg grating sensor, 1550 nm central wavelength connected to an optical spectrum analyser. The laser output stability was tested over time, from short periods of 30 minutes up to 48 hours. The EDF fibers were then tested for RIA changes after the laser pumping as some improvement in the power output was noticed.

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Faza nr. 3

Responsabil: Dr. Al. Palla-Papavlu

Termen de predare: 12.04.2019

Titlu: "Depunere prin tehnici laser și caracterizarea morfologico-structurală de materiale active hibride organic‐anorganic"

Abstract: Sensors for the detection of volatile organic compounds can recognize different gaseous compounds in the environment, thus being used in a large number of applications in everyday life. In view of the increasing demand for high performance detection devices and systems, there is a growing interest in the development and manufacture of thin film based detection devices. In particular, due to the compatibility of these materials with CMOS-based silicon technology as well as their electronic, magnetic, optical, and mechanical properties, the integration of organic-inorganic hybrid materials into sensor structures and systems offers new features and improved performance.
Functional organic materials include small molecules, oligomers and polymers, while hybrid materials include inorganic nanomaterials (such as one-dimensional carbon nanotubes) combined with an organic matrix. For many applications, the challenge is to integrate thin films into high performance and cost-effective sensors and systems. The validation of the laser material processing techniques allows the production of thin films in the field of future technology applications. For example, pulsed laser deposition, matrix assisted pulsed laser evaporation, and laser induced forward transfer are techniques which are also used in the research conducted in INFLPR, these deposition / transfer techniques being scalable and successfully used for the growth of high quality films with a very good density.
In this phase of the project, we have used a laser based technique, i.e. matrix assisted pulsed laser evaporation to deposit organic-inorganic hybrid films. Through successive optimizations, we have been able to obtain hybrid polymer: carbon nanotube films that can be further used in sensor manufacturing. The chosen approach was simple and flexible due to the fact that the polymer: carbon nanotube mixtures can easily be deposited through MAPLE on a variety of substrates without the need for prior surface functionalization.
The polymer: carbon nanotube hybrid films deposited through MAPLE have been characterized and their structural and morphological properties have been obtained. The presence of nanotubes in the films alters both the topography and surface chemistry. In addition, a larger amount of nanotubes on the surface of the hybrid films led to a more hydrophilic surface, confirmed by the results of contact angle measurements.
The first results obtained were accepted for publication (in Applied Physics A). The objectives assumed were met, and there are ongoing investigations for the realization of sensors based on organic-inorganic hybrid active materials.

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Faza nr. 4

Responsabil: Dr. I. Paun

Termen de predare: 12.04.2019

Titlu: "Imprimare laser 3D de materiale compozite biocompatibile"

Abstract: In this project, we report on novel composite magnetic scaffolds that enhance the mineralization ability in osteoblast cells. The scaffolds were fabricated by laser direct writing via two photons polymerization (LDW via TPP) of OrmoCore/magnetic nanoparticles (MNPs) composites, with submicrometric spatial resolution and having complex and reproducible architectures. MNPs 4.9+/-1.5 nm in diameter and with saturation magnetization of 30 emu/g were added to OrmoCore, in concentrations of 0, 2 and 4 mg/ml. The homogenous distribution of the MNPs from the unpolymerized OrmoCore/MNPs composite was preserved after the photopolymerization process. The presence of iron in the polymerized composite was detected in concentrations similar with the MNPs concentrations from the unpolymerized material. Importanlty, the MNPs preserved their superparamagnetic behavior. The magnetizations of the scaffolds with 2 and 4 mg/ml MNps concentrations were of 10-4 emu si 2x10-4 emu respectively, corresponding to specific magnetizations of 14 emu/g si 17 emu/g respectively. The MNPs also improved the mechanical resilience of the scaffolds and reduced their shrinkage from 80.2±5.3% for scaffolds without MNPs, down to 20.7±4.7% for scaffolds with 4 mg/ml MNPs concentration. The intrinsically magnetic cues represented by the MNPs incorporated in the scaffolds and the externally magnetic cues represented by a static magnetic field (SMF) of 1.3 T acted in synergy and promoted the cells mineralization in vitro. MG-63 osteoblast-like cells seeded on scaffolds exposed to SMF deformed the regular architecture of the scaffolds and mineralized faster in comparison to the unstimulated samples. Furthemore, the deformation of the scaffolds and the cells mineralization under SMF exposure increased with increasing MNPs concentration. The results are discussed in the frame of gradient magnetic fields of the order of 3x10-4 T/m locally generated by the MNPs over the cells bodies.

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Faza nr. 5

Responsabil: Dr. A. Matei

Termen de predare: 12.04.2019

Titlu: "Cresterea si caracterizarea de filme subtiri de montmorilonit prin tehnici laser"

Abstract: The aim of this work is to produce lamellar montmorillonite (MMT) thin films as active surfaces for the absorption of organic and inorganic pollutants from residual waters.
Montmorillonite (MMT) is lamellar clay material, part of smectite group of phyllosilicate mineral species. Unique properties, such as a chemically high surface area, a high cation exchange capacity (CEC), interlayer surfaces with unusual hydration characteristics (MMT can increase its volume several times in the presence of water), are due to the structure crystalline and chemical composition.
Pulsed laser deposition (PLD) and matrix assisted pulsed laser evaporation MAPLE are the techniques employed for the deposition of montmorillonite thin films. The deposition parameters, especially the laser wavelength and laser fluence, play an important role in the composition and morphology of the films.
The topography of the samples was investigated by AFM and SEM, and the hydrophilicity was evidenced by contact angle measurements. Structural analysis was made by XRD, EDX and XPS. The chemical structure was investigated by FTIR spectroscopy. The obtained films are adherent and compact; the film stoichiometry can be controlled by first varying the essential experimental parameters (wavelength / fluency / laser method). The films deposited by laser techniques are hydrophilic, with contact angles that can reach below 10°.

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Faza nr. 6

Responsabil: Dr. C. Ristoscu

Termen de predare: 15.05.2019

Titlu: "Substraturi tip implant functionalizate cu apatita biomimetica prin metode laser"

Abstract: We report the deposition by Matrix-Assisted Pulsed Laser Evaporation (MAPLE) technique of biomimetic nanocrystalline apatite coatings on titanium substrates, with potential application in tissue engineering. The targets were prepared from metastable, nanometric, poorly crystalline apatite powders, analogous to mineral bone, synthesized through a biomimetic approach by double decomposition process. For the deposition of thin films, a KrF* excimer laser source was used ( λ= 248 nm, τFWHM ≤25 ns). The analyses revealed the existence, in synthesized powders, of labile non-apatitic mineralions, associated with the formation of a hydrated layer at the surface of the nanocrystals. The thin film analyses showed that the structural and chemical nature of the nanocrystalline apatite was prevalently preserved. The perpetuation of the non-apatitic environments was also observed. The study indicated that MAPLE is a suitable technique for the congruent transfer of a delicate material, such as the biomimetic hydrated nanohydroxyapatite.

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Faza nr. 7

Responsabil: Dr. C. Gheorghe

Termen de predare: 14.05.2019

Titlu: "Investigarea emisiei in vizibil a ionilor Tb3+ si Tb3+‐Yb3+ in monocristale laser si ceramici de tip CNGG"

Abstract: Spectroscopic investigation of Tb3+ and Tb3+‐Yb3+ ions doped Ca3(Nb,Ga)5O12 (CNGG) single crystal and ceramics were performed in order to assess their potential as a laser materials and phosphors for visible emission. Tb:CNGG and Tb‐Yb:CNGG single crystals were grown by the Czochralski method and ceramics samples were obtained by solid state reaction. All the samples were investigated by optical spectroscopy. Based on low temperature absorption and emission spectra, partial energy level diagram of Tb3+ doped CNGG single crystal were obtained. The energy transfer (TE) processes in Tb, Yb: CNGG co‐doped ceramics samples were investigated. Emission schemes with applicative potential for the investigated materials were evaluated.

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Faza nr. 8

Responsabil: Dr. A. Popescu

Termen de predare: 14.06.2019

Titlu: "Gravare laser in relief prin placare laser"

Abstract: This research involves marking of metallic objects with protruding metallic characters by laser cladding. The set-up consists of a powder feeder, a high power IR laser source and a robotic arm. The team accomplished this objective and obtained both unfilled and filled characters, logos and patterns. The material of choice for these experiments was Ti6Al4V. Two types of substrates were used, one of graphite and a metallic one made of Ti. Depositions on graphite were rough and had reduced adherence, while on the metal substrate, the resolution increased significantly. In order to fill the characters with metal content, a meander type pattern for the robotic arm was created, with several distances between it’s lines in the range 0.1-2 mm, which produced various degrees of finesse for the texturing of the filling material. A separation of 0.1 or 0.2 mm between the lines produced a higher finesse of the filling, but caused metal accumulation at the borders of the meander, where the robot slows down for changing the movement direction. The minimal length of characters was determined to be of 10 mm, i.e. approximately the thickness of a deposited line. Bellow this value, marking by laser cladding produced unidentifiable shapes due to the lines thickness. On the opposite side, the maximal size of marking by cladding is of the order of 1 m, limited by the robot’s arm length. Such laser markings using metallic materials can find uses in publicity, art, but also in industry for marking of parts, writing of bar codes or gravure of security elements.

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Faza nr. 9

Responsabil: Dr. T. Acsente

Termen de predare: 14.06.2019

Titlu: "Optimizarea procesului MSGA (pulverizare magnetron si agregare in flux de gaz) in vederea controlului dimensiunii nanoparticulelor de W si a stabilizarii ratei de depunere"

Abstract: During the past years we implemented in INFLPR (Low Temperature Plasma Laboratory, Plasma Processes, Materials and Surfaces Group) an experimental system for production of W nanoparticles using a plasma based method: magnetron sputtering and vapor condensation in an inert gas stream (MSGA). The W nanoparticles produced by this method have been and are still used in nuclear fusion research involving INFLPR. The operation of the MSGA nanoparticle source in Ar for the production of W nanoparticles has a major drawback: the nanoparticle synthesis rate drops to zero over a finite time interval (maximum 30 minutes), limiting the amount of nanoparticles produced during a deposition batch . Following the studies performed in this project stage, we implemented an experimental method to eliminate this disadvantage. The method is based on the intentional and controlled admission of a gas (H2) into the magnetron discharge in mixture with the main working gas (Ar), to stimulate the nucleation process of the W nanoparticles. This experimental procedure ensures a nanoparticles deposition rate which is constant over time. This rate is higher than that obtained only in Ar. Also, the metallic character of the synthesized nanoparticlesis preserved. In this phase of the project we performed and a parametric study of the W nanoparticles synthesis process. During the study were produced W nanoparticles samples which were investigated by SEM electronic microscopy, in order to establish the distribution of nanoparticle sizes on each sample. Following these investigations we established a correlation between the considered parameters and the dimensions of the synthesized nanoparticles. Thus, we established a way for efficiently control of the W nanoparticle size produced by MSGA: by appropriately modifying an experimental parameter (pressure in the MSGA source) and / or a constructive one (the diameter of the extraction nozzle of the MSGA source).

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The substrate on which W nanoparticles are deposited is moved in the front of the MSGA source at a speed of 0.1 mm/s (see photo of the substrate).
Operating the magnetron discharge only in Ar would lead to reduction of the deposition rate of W nanoparticles in 90 s from the beginning of the process (see the seed like spot from a tob on the substrate).
The introduction of 5% H2 in the magnetron discharge leads to the regeneration of the nanoparticle synthesis process (see region from c to d on the substrate).


Faza nr. 10

Responsabil: Dr. C. Achim

Termen de predare: 12.07.2019

Titlu: "Spectroscopia in infrarosu pentru evaluarea calității plantelor și fructelor"

Abstract: Over the last couple of decades, with the rapid development of the economy and improvement of living standards, fruit consumption has increased significantly and consumers have higher expectations of fruit qualities. However, many fruit quality attributes are still tested using traditional approaches which are either subjective or time-consuming, so that the evaluation of fruits nondestructively and rapidly has become a research hotspot. Researchers all over the world have investigated the potential of various technologies, including acoustic techniques, spectroscopic techniques and electronic noses, for the assessment of fruit qualities. Among all these technologies, spectroscopic techniques have drawn great attention for their prominent advantages: (1) they are nondestructive methods which enable the acquisition of fruits’ internal quality parameters without damaging their surfaces; (2) the measurement processes are simple and rapid, as no complex pretreatments or chemical reactions on fruit samples are needed; (3) they enable the detection of several fruit internal attributes simultaneously.
Infrared spectroscopy plays an important role in the evaluation of a larger number of gases released by flowers, plants and fruits subject to external environmental factors. The measurements from this research phase will use experimental setup detection capable of detecting and measuring gas concentrations up to parts per billion of the photoacoustic signal based on the selectivity of a CO2 laser source. This is significant because the experimental research is an interesting application for a new emerging trend: food quality. The impact of dietary exposure to heavy metals (known risk factors) at typical levels found in/on food is less readily established so that pre-assessment of food is necessary before human ingestion. The technique of this research provides the benefits of assessing health by monitoring the concentration of gases from the respirations of plants, flowers and fruits exposed to abiotic stress, which can be metabolized in the body with adverse effects on human health. Ethylene has been shown to be metabolized in ethylene oxide, according to the International Agency for Cancer Research, ethylene oxide being a carcinogen.
The proposed phase focuses on those stress factors that can alter the quality of food and intends to evaluate as many gas as possible using infrared spectroscopy.

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Faza nr. 11

Responsabil: Dr. E. Axente

Termen de predare: 12.07.2019

Titlu: "Proiectare, caracterizare si testare a unei platforme pentru controlul curgerii in dispozitive microfluidice - Partea I (Proiectarea)"

Abstract: At this stage of the project, we advanced and realized the design of an innovative microfluidic platform, both in a basic, and a complex version respectively. The main components and their characteristics are described, the best features to achieve performant perfusion systems for biomedical applications being evidenced. Among those, one can mention: stable and pulsations free flows, small response time (< 10 ms), accurate flow control in the nL/min – mL/min range, the possibility of sequential injection of different liquids (fast flow switch), the generation of flow regimes that simulate the physiological conditions, the posibility of instant flow-stop for investigations. A broad spectrum of possible applications were descibed, as for example: cell cultures in biochips, biological assays at single-cell level, investigation of cell response due to medium switch, controlled drug delivery, studies in bioreactor-like conditions, cytotoxicity assays, dynamical cells imaging in real time, stem cells analyses, but also chemical synthesis in microfluidic devices, spectrochemical and biochemical analyses, biodetection and biosensors, micro-droplet generation and manipulation in chips, optofluidics. We performed the CAD design of a microfluidic biochip for flow control and concentration gradient biomolecular transport investigations. The experimental in silico design for controlled perfusion of the microfluidic device was created. We may thus simulate molecules difusion or transport under the influence of distinct parameters like temperature, pressure, flow, flux, concentration, etc. We consider that our proposed objectives were fully achieved, and the perspectives for further project development considered, which represent a new approach in the research and development field in our country.

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