Liliana Bizo | Babes-Bolyai University (original) (raw)

Papers by Liliana Bizo

Environmental Engineering and Management Journal, 2013

Waste recycling represents a very significant issue for the protection of our environment. Large ... more Waste recycling represents a very significant issue for the protection of our environment. Large waste quantities (slag and ashes) are products of the coal extraction industry and its subsequent combustion in thermal power stations. The possibilities of obtaining crystallized glasses in the CaO-Al 2 O 3-Fe 2 O 3-SiO 2 system by introducing in the raw materials mixture ashes from Mintia Deva thermal power station have been studied. The physical and chemical characterization of the thermal power station ash has been performed. Crystallized glass samples have been obtained and characterized by thermal analysis, electronic microscopy and X-ray diffraction.

Computer-aided chemical engineering, 2010

ABSTRACT Transparent conducting oxides have become an important topic in the field of optoelectro... more ABSTRACT Transparent conducting oxides have become an important topic in the field of optoelectronics for various devices and numerous investigations have been carried out recently on these materials. Due to the significant stabilizing effect of introduction of W 6+ cations in a M 7 O 12 structure, we are interested in the problem of formation a solid solution between In 4 Sn 3 O 12 and In 6 WO 12 , implementing the fully compensated cationic substitution: 3Sn 4+ → 2In 3+ + W 6+ . Correlated predictions of properties or trends based on experimental measurements are important factors to reduce the costs of future researches in order to obtain new transparent conducting oxides. To avoid some major drawbacks of any regression techniques a potential support is the integration of artificial intelligence innovative ideas. The paper implements a novel procedure of the artificial intelligence based on support vector machine in a minimax approach. The procedure, involving a link between artificial intelligence and materials science, is able to reveal parameters or to predict particular variables, properties or trends. The main goal of the paper is to compare the performance of the procedure with regression techniques and to promote it as an effective technique in material science. Comparative numerical experiments with regression techniques demonstrate the capability of the proposed procedure. Presented numerical experiments reveal the real capacity of this procedure for engineers dealing with material science analyses and beyond these to many others engineering domains.

Studia Universitatis Babes-bolyai Chemia, Sep 30, 2020

Endodontic sealers are designed to be used in conjunction with semi-rigid materials during endodo... more Endodontic sealers are designed to be used in conjunction with semi-rigid materials during endodontic treatment, in order to obtain a three dimensional obturation of the root canal. During the last years, tricalcium silicate (C3S), due to its increased biocompatibility, and superior physicochemical properties, has been investigated as an important component of endodontic filling materials. For most materials available on the market the source of C3S alongside C2S is MTA (mineral trioxide aggregate), but obtaining C3S through synthesis is considered to be a much better alternative due to its superior purity and controlled size of the particles. In this study C3S was synthetized in nanosized particles, by sol-gel method, from TEOS and calcium nitrate tetrahydrate without or with mineralizer NaF. A study was conducted in order to analyze the obtained powder and the hydrated samples which were prepared by mixing the powder with water in a ratio of 0.4, and cured for 28 days. The dried gels were thermally treated at 1450 ºC respectively at 1350 ºC. XRPD and TEM revealed the main presence of nanosized tricalcium silicate besides dicalcium silicate and small quantities of calcium hydroxides at both of synthesis temperatures. The hydration compounds evidenced by XRPD were calcium silicate hydrate alongside calcium hydroxide and calcium carbonate. FTIR analysis evidenced the specific vibration bands for O-H and Si-O bounds in hydrated calcium silicates.

La preparation et l’etude cristallochimique et physique de nouveaux oxydes conducteurs transparen... more La preparation et l’etude cristallochimique et physique de nouveaux oxydes conducteurs transparents ont ete realisees dans des systemes chimiques a base d’oxyde d’indium. Les differents composes et solutions solides appartiennent tous au type fluorine deficitaire des oxydes MO2-x soit le modele bixbyite pour x = 0,5 soit celui des oxydes M7O12 pour x = 0,29. Deux resultats majeurs sont obtenus : 1° la presence d’antimoine au degre oxyde (V) dans In2O3 comme dans le type M7O12 observee pour la premiere fois, entraine de tres bonnes proprietes de conductivite electrique et de transparence optique, a l’exemple de l’oxyde d’indium dope a l’antimoine IAO. 2° les substitutions cationiques compensees de l’indium par des paires cationiques bivalent (Zn, Cu)/pentavalent (Sb) ou tetravalent (Sn) permettent aussi d’acceder aux proprietes typiques de la conductivite transparente, en particulier une resistivite electrique inferieure a 10-3 Ωcm. L’etude cristallochimique par diffraction des Rayons-X et diffraction neutronique en temps de vol a conduit a des informations precises sur la variation des parametres de maille des solutions solides, l’evolution des distances metal-oxygene et la distribution cationique : ce dernier point est d’un grand interet dans le cas present, celui des ions isoelectroniques type 4d10 In3+, Sn4+, Sb5+ et Te6+. Le fait le plus novateur de ces resultats tient au fait que les proprietes physiques de conductivite et de transparence optique sont obtenues de facon tres simple, a l’issue des traitements thermiques de synthese a l’air. Le recours a toute operation chimique reductrice comme c’est le cas pour elaborer le compose de reference ITO apparait donc superflu.

Studia Universitatis Babes-bolyai Chemia, Sep 30, 2017

The effect of coupled substitution of Zr 4+ /Ga 3+ for In 3+ in In 2 O 3 upon the structural, ele... more The effect of coupled substitution of Zr 4+ /Ga 3+ for In 3+ in In 2 O 3 upon the structural, electrical and optical properties has been studied. The In 2-2x Ga x Zr x O 3 solid solution with bixbyite structure has been synthesized for 0 ≤ x < 0.15. A decrease in resistivity for the composition x = 0.025 (ρ RT = 5.5x10-3 Ω.cm) by approximately one order of magnitude if compared to In 2 O 3 (ρ RT = 2.2x10-2 Ω.cm) was obtained. The maximum percent reflectance around 500 nm is lowered by 15% with respect to pure In 2 O 3. These novel oxides show their potential as transparent conductors.

Materials, Sep 7, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Ceramics International, Mar 1, 2021

Nano-hydroxyapatite (nano-Hap) and different Hap-based nanocomposites (NCs) containing nanocarbon... more Nano-hydroxyapatite (nano-Hap) and different Hap-based nanocomposites (NCs) containing nanocarbons with different morphologies (functionalized multiwall carbon nanotubes-fMWCNT, graphene oxide-GO, and fullerene-Ful), and gelatin (Gel) were studied to highlight the modification of their adsorption and desorption properties. The obtained Hap-based NCs were characterized using powder X-ray diffraction, laser diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. Moreover, ultraviolet-visible spectroscopy was used to investigate the adsorption and desorption properties of the obtained NCs. The adsorption experiments were performed with both ibuprofen (IBU, synthetic active substance) and anthocyanin (ANTO, natural active substance). The results revealed that the studied additives had little influence on improving the drug adsorption as compared to pure HAP. The adsorption energies were evaluated using density functional theory (DFT), which indicated that the interaction with GO is much stronger than the interaction with Ful, due to the formation of hydrogen bonds. The desorption experiments were carried out in simulated body fluid (SBF). fMWCNT and GO had a positive effect in the case of both natural and synthetic anti-inflammatory drugs, due to the morphology and the intermolecular interactions between the functional groups. The positive effect of Gel was observed in the adsorption studies of both substances, Gel increased the adsorption capacity of the NCs. The release profile of IBU was carried out using various mathematical models (zero-order, first-order, Higuchi, Hixon-Crowell, and Korsmeyer-Peppas).

Advanced Functional Materials, Mar 11, 2008

Solid State Sciences, Oct 1, 2004

Optical properties D 6000 Antimony and Antimony-Tin Doped Indium Oxide, IAO and IATO: Promising T... more Optical properties D 6000 Antimony and Antimony-Tin Doped Indium Oxide, IAO and IATO: Promising Transparent Conductors.-New promising transparent conducting oxides In 2 O 3 doped with 3% Sb (IAO) and In 2 O 3 co-doped with 5% Sb and 5% Sn (IATO) are prepared from mixtures of In 2 O 3 and Sb 2 O 3 (SnO 2) at 900-1400°C. In these doped oxides, the maximum percent reflectance around 500 nm is decreased by more than 20% with respect to undoped In 2 O 3. The resistivity is decreased by one order of magnitude in IAO and nearly by two orders of magnitude in IATO with respect to undoped In 2 O 3 ceramics.

Materials Research Bulletin, Dec 1, 2006

ABSTRACT Two solid solutions In2−xM2x/3Sbx/3O3 (M = Cu, Zn) with the bixbyite structure have been... more ABSTRACT Two solid solutions In2−xM2x/3Sbx/3O3 (M = Cu, Zn) with the bixbyite structure have been synthesized in air at 1300 °C. The homogeneity range is larger for Zn (x = 0.42) than for Cu (x = 0.20) and the cationic distribution of the Cu/Sb and Zn/Sb couples is weakly ordered. These new oxides appear to be transparent conductors. Even fully deprived of tin, they have good potential properties. These oxides are either semiconductors with a small band gap (Cu/Sb) or semimetals (Zn/Sb) with σ = 3 × 102 (Ω cm)−1 at room temperature. These materials are more efficient than bulk ITO prepared under the same experimental conditions, i.e. without reducing treatment (σ = 50 (Ω cm)−1).

Journal of Solid State Chemistry, Mar 1, 2007

The cation ordering in the fluorite-like transparent conductors In 4+x Sn 3À2x Sb x O 12 and In 6... more The cation ordering in the fluorite-like transparent conductors In 4+x Sn 3À2x Sb x O 12 and In 6 TeO 12 , was investigated by Time of Flight Neutron Powder Diffraction and X-ray Powder Diffraction (tellurate). The structural results including atomic positions, cation distributions, metal-oxygen distances and metal-oxygen-metal angles point to a progressive cation ordering on both sites of the Tb 7 O 12type structure with a strong preference of the smaller 4d 10 cations (Sn 4+ , Sb 5+ , Te 6+) for the octahedral sites. The corresponding increase of the overall structure-bonding anisotropy is analyzed in terms of the crystal chemical properties of the OM 4 tetrahedral network of the antistructure. The relationships between the M 7 O 12 and the M 2 O 3 bixbyite-type structures are explored. Within the whole series of compositions In 4+x M 3Àx O 12 (M ¼ Sn, Sb, Te) there exists an increase of the symmetry gap between the more symmetrical bixbyite structure and the M 7 O 12 type. This is tentatively correlated with the progressive weakening of thermal stability of these compositions from Sn to Te via Sb.

Studia Universitatis Babes-bolyai Chemia, Jun 30, 2020

15 at% Mg-doped ZrO2 ceramic material was synthesized by solid-state reaction at 1600 ºC. Particl... more 15 at% Mg-doped ZrO2 ceramic material was synthesized by solid-state reaction at 1600 ºC. Particle size analysis of raw materials mixture depicts the formation of a narrow particle size distribution (PSD) with a mean particle size of about 56 nm. The structural analysis confirms that the assynthesized Mg-doped ZrO2 product is of pure tetragonal phase (t-ZrO2) with a crystallite size of 55.76 nm. The UV-VIS diffuse reflectance spectrum (DRS) showed a maximum %R at 550 nm and the estimated optical bandgap was about 3.83 eV. The morphology of the sample examined by scanning electron microscopy (SEM) shows interconnected grains in the sintered ceramics. Moreover, EDX analyses confirm the presence of Mg, Zr, and O, with a homogenous distribution throughout the sample.

Studia Universitatis Babeș-Bolyai Chemia

Two commercial stoneware pastes traditionally used to produce ceramic objects were evaluated. The... more Two commercial stoneware pastes traditionally used to produce ceramic objects were evaluated. The objective was the comparative characterization of the pastes and to find the most suitable to obtain fine ceramic objects using the pottery wheel. Both ceramic pastes were characterized by X-ray powder diffraction (XRPD), particle size analyses (laser diffraction) and thermal analyses (thermogravimetry-TG, its derivative-DTG, and differential thermal analysis-DTA). The technological properties like linear drying and firing shrinkage, moisture content and plasticity were also determined. The results showed that both pastes have appropriate properties making them suitable for plastic shaping by pottery wheel. In addition, the stoneware paper clay paste is "greener" due to its content of cellulose fibers which can come even from recycled paper.

Materials

Zirconia-based bioceramics, one of the most important materials used for dental applications, hav... more Zirconia-based bioceramics, one of the most important materials used for dental applications, have been intensively studied in recent years due to their excellent mechanical resistance and chemical inertness in the mouth. In this work, the structural, morphological and dissolution properties of the Zr1−xMgxO2 (x = 0.05, 0.1, 0.15, 0.2, 0.25, and 0.3) system, prepared by the conventional ceramic method, were evaluated before and after immersion in saliva substitute gel (Xerostom®, Biocosmetics Laboratories, Madrid, Spain), one of the most common topical dry mouth products used in dentistry. The X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) techniques were employed to investigate the phase transformations and morphology of the ceramics during the degradation process in Xerostom®. In vitro analyses showed overall good stability in the Xerostom® environment, except for the x...

Ceramics International

Materials, 2022

The present study aimed to prepare nanofibers by electrospinning in the system polylactic acid-hy... more The present study aimed to prepare nanofibers by electrospinning in the system polylactic acid-hydroxyapatite-doxycycline (PLA-HAP-Doxy) to be used as a drug delivery vehicle. Two different routes were employed for the preparation of Doxy-containing nanofibers: Immobilization on the electrospun mat’s surface and encapsulation in the fiber structure. The nanofibers obtained by Doxy encapsulation were characterized using Fourier transform infrared (FTIR) spectroscopy, thermogravimetric (TG) and differential thermal analyses (DTA) and scanning electron microscopy (SEM). The adsorption properties of pure PLA and PLA-HAP nanofibers were investigated for solutions with different Doxy concentrations (3, 7 and 12 wt%). Moreover, the desorption properties of the active substance were tested in two different fluids, simulated body fluid (SBF) and phosphate buffer solution (PBS), to evidence the drug release properties. In vitro drug release studies were performed and different drug release ki...

Studia Universitatis Babeș-Bolyai Chemia, 2020

In the present work, zirconia-based biocomposites were prepared by adding different amounts of an... more In the present work, zirconia-based biocomposites were prepared by adding different amounts of antibacterial magnesium oxide and bioactive and biocompatible hydroxyapatite (HAP). The biocomposites were synthesized by the conventional ceramic processing route. The structure and morphology of the materials were investigated using X-ray powder diffraction (XRPD), scanning and transmission electronic microscopy (SEM and TEM). The stability of the tetragonal structure of ZrO2 was confirmed by XRPD analyses. Moreover, their bioactivity was studied by soaking the samples in artificial saliva (AS) to evaluate the effect of MgO and HAP on the biological performances of the prepared biocomposites. UV-VIS analyses carried out on artificial saliva after immersion of the prepared materials showed that MgO plays an important role in the post-immersion dissolution process.

In order to discover new n-type or p-type transparent conductors numerous investigations have bee... more In order to discover new n-type or p-type transparent conductors numerous investigations have been carried out recently on transparent conducting oxides materials. Our work presents a new In5.5+xSb1.5-3xW2xO12 solid solutions prepared by solid-state reactions. Many expensive experiments for optical diffuse reflectance and electrical resistivity were realised to characterise this solid solution. To reduce the time and costs of future researches in order to improve or to obtain new transparent conducting oxides, predictions of new properties based on experimental measurements are important factors. To achieve this goal the paper implements ideas of artificial intelligence based on support vector machine in a minimax approach. The implemented procedure, named minimax decision procedure involving a link between artificial intelligence and material science, is able to predict particular variables, properties or trends. In a comparative manner, the paper presents the performance of the pr...