Neculai Aelenei

Neculai Aelenei
Gheorghe Asachi Technical University of Iasi | TU Iasi · Department of Chemical Engineering

PhD

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30
Publications
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547
Citations

Publications

Publications (30)
Article
Two types of microparticles based on alginate and chitosan with encapsulated ciprofloxacine (CF) were prepared directly, by ionic exchange. The particles were characterized by FTIR spectroscopy and analyzed by termogravimetric techniques. The FTIR specters indicated the presence of the polymer-drug complex obtained via electrostatic interactions be...
Article
The preparation of microspheres containing chitosan, sodium alginate and ibuprofen and the pH dependent drug release were investigated. The microspheres were prepared by two experimental routes: the first one starting with a chitosan/ibuprofen core subsequently coated by an alginate shell (S1) and the second one based on an alginate/ibuprofen core,...
Article
Chitosan, a natural polycationic polysaccharide, was coupled with two polyanionic polymers: Na-alginate and carboxymethylcellulose (CMC) and with tannic acid (TA) obtaining three species of self-assembled complexes: chitosan/alginate/TA (sample 1), chitosan/TA (sample 2) and chitosan/CMC/TA (sample 3). The microparticle formation was achieved by dr...
Article
Generally, the metallic implants do not exhibit any bio-integration properties in contact with bone tissues. The ceramic implants for similar applications are very difficult to use due to their mechanical properties, especially fracture toughness and elasticity modulus. To improve the interfacial properties of metallic implants in contact with bone...
Article
The aim of this work was to study the effect of electrochemical and electrophoretic deposition of hydroxyapatite (HA) on commercial pure titanium substrates, regarding the corrosion behaviour of the coated biomaterials during their preservation in physiological media. The coated surfaces were analyzed by X-Ray Diffraction and Scanning Electron Micr...
Article
The possibilities offered by Electrochemical Impedance Spectroscopy (EIS) technique for studying the progress of corrosion in high-strength low alloys (HSLA) was investigate. Corrosion test were performed in aerated natural seawater (Atlantic Ocean, Gran Canaria). Impedance diagrams provide the value of charge transfer resistance (R(ct)). For the c...
Article
The thermal behavior of several chitosan/alginate /drug microparticle formulations containing ciprofloxacin, ibuprofen, ketoprofen or tannic acid was investigated by thermogravimetry in inert atmosphere in the temperature range of 25 – 900oC. The chemical composition and the method used for drug incorporation influenced the thermal stability of the...
Article
The electrochemical behavior of a three Ag-Pd alloys used in dental prosthetics construction for crowns and bridges was studied in artificial saliva using the polarization curves and electrochemical impedance spectroscopy (EIS). The corrosion resistance was evaluated by means of the corrosion currents value and by coulometric analysis. The open cir...
Article
Based on the polarization curves and electrochemical impedance spectroscopy (EIS) in the case of three commercial alloys (Wirolloy, NicromalSoft and VeraSoft) maintained in artificial saliva, it was established the type and the intensity of the corrosion process by means of the corrosion currents value. The passivation of all the samples occurred s...
Article
Electrochemical impedance spectroscopy (EIS) measurements were used to characterize the electrochemical behaviour of the some commercial dental alloys: two PdAg based alloys (Paliag, PaliagMaestro), two NiCr based alloys (Wirolloy, VeraSoft), two CoCr based alloys (Vitallium, VeraPDI) and two CuAl based alloys (Gaudent, NPG+2) in artificial saliva....
Article
Degradation of bisphenol A (BPA) was carried out with the Fenton reagent with and without additional sonochemical treatment. The Fenton and the sono-Fenton decomposition of BPA showed that ultrasound irradiation of wastewater improved the wet oxidation process of 25 mg l(-1) BPA solutions. The sonochemical degradation of BPA was monitored using UV...
Article
We have synthesized a new Ti-based alloy that combines Ti with the non-toxic elements Ta and Mo. Ingot of composition Ti-12Mo-5Ta was prepared by melting pure elements in an arc-melting furnace. The alloy was annealed at 950 degrees C for 1 h under high vacuum and quenched in water at room temperature. The alloy was characterized by X-ray diffracti...
Article
Full-text available
Five non-precious Ni-Co based alloys were analyzed with respect to their corrosion behaviour. The correlation between the amount of the elements Cr, Mo, V and the corrosion behaviour, expressed by the PREN (pitting resistance equivalent number) index in the case of the allied steels, was extended for Ni-Cr and Co-Cr dental alloys characterization....
Article
Full-text available
RECEIVED DECEMBER 2, 2002; REVISED OCTOBER 24, 2003; ACCEPTED DECEMBER 24, 2003 The paper presents a study on the physicochemical properties of some new symmetrical diquaternary salts of 4,4¢-bipyridine. The properties refer to the acid-basic and thermal behav-ior of these compounds. The chemical stability of these salts in solution was found to be...
Article
The sonolytic degradation of cyanide ions (CN⁻) in the presence of two oxidising agents: hydrogen peroxide and atmospheric oxygen was investigated in order to emphasise the influence of the initial value of the pH on the efficiency of the degradation process. The results prove that the pH value has a significant influence only on the process involv...
Article
Taking into account the practical importance of the electrochemical oxidation of the CN⁻ ion from wastewaters, a systematically study was preformed, regarding the influences of the anode nature, current density, temperature and Cu²⁺ concentration on the rate of the overall electrolytic process. The cell optimal parameters were found to be: nickel a...
Article
The thermal stabilities of polystyrene (PS), polysulfone (PSF), poly(p-chloromethyl) styrene (CMPS), chloromethylated polysulfone (CMPSF), and their corresponding derivatives substituted with 2-(N,N-dimethylamino)ethanol (HAPS, HAPSF) or triethylamine (APS, APSF) were investigated. The influence of the chemical structure on the thermal stability wa...
Article
Cyanide (CN-) is a species of high toxicity found mostly in industrial effluents, which always put a serious problem for environment. Hence, during the evolution of environmental engineering, a large number of procedures have been proposed for treatment of cyanides. This paper presents a study on the ultrasound capacity to enhance the cyanide from...
Article
Full-text available
This paper presents a comparative study on the capacity of some oxidizing agents: hydrogen peroxide, atmospheric oxygen and barium peroxide to destroy cyanide ions under ultrasound irradiation. Special at-tention was directed towards hydrogen peroxide activity with or without sonication.
Article
Thermal behaviour of trimethylsilylcellulose, triethylsilylcellulose and triphenylsilylcellulose has been studied by thermogravimetry, on analysing the influence of the substitution degree, molecular weight and substituent nature on the thermostability of these compounds. A complex oxidation/depolymerization mechanism was evidenced at lower degrees...
Article
The potentiodynamic polarization methods have been employed to evaluate the corrosion resistance of the Gaudent-S dental alloy in a slightly acid artificial saliva (Fusayama's saliva; pH = 6.18), a slightly alkaline artificial saliva (Rondelli's saliva; pH = 7.75) and in an acid saline solution (NaCl/lactic acid; pH = 2.64). The results were compar...
Article
In order to obtain some silylcellulose derivatives, five types of celluloses with different polymerization degrees (DP =327–1100) were used. The obtained silylcellulose derivatives were characterized from the crystallinity point of view as a function of both the substitution degree and characteristics of the used celluloses in their synthesis. The...
Article
The paper deals with thermal behaviour of some celluloses and trimethylsilyl celluloses, along with the evaluation of the compensation effect for the studied samples. The data processed by the TG and respectively, DTG method, correlated with the mechanism of thermal degradation, suggest a kinetic compensation effect, supramolecular structure playin...
Article
Neomycin is coupled on xanthan--a polysaccharide of microbial biosynthesis produced by Xanthomona campestris--through ionic complexation. The kinetics of neomycin release, in vitro, at pH = 8.2 is studied. A release of neomycin, following a zero order kinetics, is observed, regardless of the eluent flow-rate. The neomycin-xanthan complex, protected...
Article
The kinetics of delayed release neomycin-xanthan complex, and its antimicrobial activity, were studied. Delayed release neomycin (53.13% free neomycin) had zero-order release kinetics, when artificial tear solution was used as eluent. Microbiological tests revealed an activity of 380 units/mg, 10% higher than neomycin in its free form.
Article
Factors that may influence experimental measurements of osmotic pressure are analysed. Measurements with new membranes in the osmometer show that a period of 50–60 hr is necessary for the membrane relaxation. The influence of the porosity of the membrane upon the values of Mn and A2 for polydisperse samples, and especially for samples with relative...
Article
Modifications due to the β-radiations of 204Tl on polystyrene in dilute benzene solutions have been studied by light scattering and viscometric measurements. Although the molecular weights of the samples are not affected, increase from 0.73 to 0.93 of the exponents of the Mark-Houwink equation was observed. From attempts to explain this high value...
Article
The viscous flow parameters for dilute PVC tetrahydrofuran solutions were determined in the temperature range 10–45°. The temperature dependence of the viscosity of the solutions obeys an Arrhenius-type equation. The concentration and the molecular weight dependence of the pre exponential factor of this equation is given by the following relationsh...

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