Inscriere cercetatori

Premii Ad Astra

premii Ad Astra

Asociația Ad Astra a anunțat câștigătorii Premiilor Ad Astra 2022: http://premii.ad-astra.ro/. Proiectul și-a propus identificarea și popularizarea modelelor de succes, a rezultatelor excepționale ale cercetătorilor români din țară și din afara ei.

Asociatia Ad Astra a cercetatorilor romani lanseaza BAZA DE DATE A CERCETATORILOR ROMANI DIN DIASPORA. Scopul acestei baze de date este aceea de a stimula colaborarea dintre cercetatorii romani de peste hotare dar si cu cercetatorii din Romania. Cercetatorii care doresc sa fie nominalizati in aceasta baza de date sunt rugati sa trimita un email la cristian.presura@gmail.com

Publicatii proprii

Structural characterization of hydroxyapatite layer coatings on titanium supports

This paper presents a study on an alternative coating method based on biomimetic techniques which are designed to form a crystalline HA layer in a manner similar to the process of natural bone formation. The HA formation on the surface of titanium alloy pretreated with NaOH solution is investigated. Two types of solutions such as supersaturated calcification solution (SCS) and modified SCS (M-SCS) were used to investigate bone-like apatite formation

Read more
Structure of mixed matrix membranes made with SAPO-5 zeolite in polyurethane matrix

SAPO-5 zeolite has been used to modify the structure of polyurethane membranes and to improve their properties. Scanning electron microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR), Bubble-point test, water permeability, swelling in water and several alcohols (methanol, ethanol, 1-propanol and 1-butanol) and density measurements have been used to study the incorporation of SAPO-5 zeolite in polyurethane membranes, the changes of supramolecular

Read more
New hybrid nanostructures based on oxacillin–hydrotalcite-like anionic clays and their textural properties

New hybrid nanostructures based on inorganic matrices of hydrotalcite-like anionic clays (HT) incorporated with oxacillin are obtained by using calcinations-restructure method. XRD and TEM analyses are used to study the structural and textural characteristics of the clay containing hybrids. When nanoparticles of iron oxides are loaded on the layered anionic clay matrix a more effective delivery system of the drug is obtained. The results can be used

Read more
SEM and EDX studies of bioactive hydroxyapatite coatings on titanium implants

This work presents a study on an alternative coating method based on biomimetic techniques which are designed to form a crystalline hydroxyapatite layer very similar to the process corresponding to the formation of natural bone. The HA formation on the surface of titanium alloy pretreated with NaOH solution is investigated. Two types of solutions such as supersaturated calcification solution (SCS) and modified SCS (M-SCS) were used to investigate

Read more
Glucose oxidase vanadium substituted anionic clay as bionanocomposite formulations for biosensors applications

Chemical sensors utilizing immobilized enzymes and proteins are important for monitoring chemical processes and biological systems. Glucose oxidase (GOx) from Aspergillum Niger is a flavoenzyme that has been used to determine glucose. Among the conventional methods of enzyme deposition the main strategy consists in its entrapment in an inert matrix adsorbed on the electrode surface. We report here the synthesis and physical - chemical characterization

Read more
Fabrication of mesoporous mixed oxides containing copper and cerium by using substituted anionic clays as precursors

Copper and cerium partially substituted anionic clay was synthesized by the coprecipitation method. The XRD analysis and N2 adsorption at 77 K indicated that calcination destroys the layered matrix of the clay, giving rise to mixed oxides having a high surface area and mesoporous characteristics; SEM analysis showed that the new formed mixed oxides consist of ensembles of highly agglomerated, interconnected nanoparticles. It results from XPS that

Read more
Hydroxyapatite/polyurethane composite membranes for lead ions removal

This work describes the preparation of a hydroxyapatite/polyurethane composite membrane and their characteristics. The porous hydroxyapatite/polyurethane composite membranes were made via solvent casting process. The deposited hydroxyapatite layers were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The data suggest that the method utilized in this work can be applied to obtain deposition of coating of crystalline

Read more
Uptake of anionic surfactants from aqueous medium by using porous anionic clays with tailored properties

Layered double hydroxides, containing Mg or Zn as divalent cations in the brucite - like layer and the derived mixed oxides obtained after the calcination process of the clays have been used to remove the anionic surfactant, sodium dodecylbenzenesulfonate, from aqueous solutions. The property of the layered clay to reconstruct its structure by using its structural "memory effect" has been used as a controlled variable parameter during the adsorption/

Read more
Oleate-LDH Hybrids by the Successive Use of the Clay Structural ”Memory Effect”

Oleate/LDH composites have been obtain by calcination-reconstruction procedures by the successive uses of the anionic clay memory effect. XRD and FTIR analysis were used to study the structural characteristics of the hybrid samples. The amount of oleate in the hybrid formulation of the clay matrix is highest after the second calcination-reconstruction cycle. After the fourth cycle the clay structure is not recovered anymore. This result points out

Read more
Electrolyte removal by mixed matrix membranes based on polyurethane

The membrane processes play a significant role in the water and wastewater treatment to remove dissolved solids, especially electrolytes. In this study, the asymmetric mixed matrix membranes based on polyurethane and SAPO-5 zeolite were used on electrolyte (NaCl) removal from water. Using a low operating pressure, the membrane performances (i.e., pure water permeation, flux and salt rejection) were measured. All membranes were showing an increase

Read more