science
SERIA B
Chimie și Știința Materialelor
Excelență în Cercetare
Din 1929
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BIODEGRADABLE BLENDS BASED ON PHB AND WOOD FIBER
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Mihai DIMONIE, Maria RÃPÃ
Five recipes based on poly-3(hydroxybutyrate) (PHB), wood fiber (WF) and epoxidated soy-bean oil (LSA) were prepared by Brabender Plastograf, at 170 0C. It was found that with increasing wood fibers content in the PHB matrix, the tensile strength and the melting temperature decrease, due to the...
SOLID-PHASE SUPPORTED CHIRAL TRICARBONYL-CHROMIUM COMPLEXES
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Matei D. RAICOPOL, Roxana LEHÃDUª, Cristina OTT, Raluca STAN, Sorin I. ROªCA
We disclose the synthesis of some organometallic polymers containing arene- tricarbonyl-chromium complexes. Several approaches were used for this purpose, such as ligand exchange and grafting by electrophilic aromatic substitution with benzylic carbocations stabilized by tricarbonylchromium...
ENZIMES IN COTTON BIO-SCOURING
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Michaela Dina STÃNESCU, Mihaela DOCHIA, Magdalena FOGORAªI, Monica PUSTIANU, Mircea Sorin BUCUR
The demand for new ecological technology lately enhanced, due to the strict environmental regulations introduced. Textile processes are characterized by high pollution, generated by the large amount of waste waters with acid or alkaline pH. Thus, the application of enzymatic work-up procedures...
ELECTROCHEMICAL STUDIES ON SOME INDOLIZINE CARBOXYLATES WITH POTENTIAL APPLICATION
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Maria-Laura SOARE, Magdalena Rodica BUJDUVEANU, Eleonora-Mihaela UNGUREANU, Emilian GEORGESCU
This work is devoted to the electrochemical study of ethyl 3-(4-methylbenzoyl) indolizine-1-carboxylate and ethyl 3-[(2-ethylphenyl)carbamoyl] indolizine-1-carboxylate by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). There are established the number and characteristics of the...
ENVIRONMENTAL ASSESSMENT OF CITRIC ACID PRODUCTION
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Anca NICA, Alexandru WOINAROSCHY
Citric acid is traditionally produced using the filamentous fungus Aspergillus Niger. One advantage of Aspergillus Niger is its ability of fermenting substrates which come as waste products from other process. The use of whey as carbon source is very attractive because this raw material is...
GC/MS STUDIES ON ALCOHOL DERIVATIZATION PROCEDURES APPLIED TO LEWISITE 1 DUE TO THE INCREASED INSTABILITY OF SOME ETHERS
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Gabriel EPURE, Nicoleta GRIGORIU, Laurenþiu FILIPESCU
2-Chlorovinylarsine dichloride (Lewisite 1) identification by gas chromatography is not a simple analysis, because it requires high concentration levels in sample (several mg/ml), very clean systems with new columns, a specially prepared injection port liner and on-column injection. Moreover,...
A STUDY REGARDING THE SURFACE PROPERTIES OF RUBBERS-BASED ADHESIVE ASSEMBLIES
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Dan Liviu IOAN, Ioana DUªESCU, Cãtãlin ZAHARIA, Gheorghe HUBCÃ
In this paper, based on the experimental data of surface tension of rubber solutions and contact angle, the values of some parameters involved in adhesion process, as solid-liquid surface tension, work of wetting, work of adhesion, superficial concentration and surface area occupied by an...
MICROSTRUCTURE OF PARTIALLY HYDROLYZED POLYVINYL ALCOHOLS USED IN PVC-S TECHNOLOGY
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Radu N. OLARU, Dumitru Mircea VULUGA, Florentina GEORGESCU, Daniela MARINESCU, Mihai DIMONIE
The paper presents a comparative investigation on the microstructure of different partially hydrolysed polyvinyl alcohols used in PVC-S technology. Average acetate-containing sequence length and their distribution in partially hydrolyzed polyvinyl alcohols as well as their...
HYDRODYNAMIC ASPECTS OF FLUIDIZED BED STABILIZED IN MAGNETIC FIELD
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Alina-Violeta URSU, Ileana Denisa NISTOR, Fabrice GROS, Alisa Vasilica ARUª, Gabriela ISOPENCU, Alina Monica MAREª
The paper studies the hydrodynamic of the gas/solid fluidization in a transverse magnetic field of ferromagnetic particles (commercial steel). The influence of solid (magnetic and non-magnetic particles) characteristics, and the magnetic field intensity (in the range of 0-12000 A.m-1), on the...
REMOVAL CHROMIUM POLLUTION FROM LEATHER INDUSTRIES WASTES
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Mihaela NICULESCU, Aura Dana IONIÃÃ, Laurenþiu Filipescu
Sludge and waste waters carrying chromium compounds are embarrassing environmental burdens for the both tanning and leather processing industries, as well as for many other manufacture branches involving extraction and use of the chromium chemicals. This paper approaches the chromium removal...
STRUCTURAL CHARACTERIZATION OF CHITOSAN COATED SILICON NANOPARTICLES –A FT-IR APPROACH
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Mirela DIACONU, Andreia TACHE, Sandra Ana-Maria Victoria EREMIA, Florentina GATEA, Simona LITESCU, Gabriel Lucian RADU
This paper presents our experimental results on the bio-functionalization of silicon nanoparticles (SiNP) with a polymer, chitosan. The procedure consists of two steps and it was developed in order to bind efficiently and effectively chitosan biopolymer to the silicon nanoparticles surface....
THRESHOLDED OPERATING PARAMETERS IMPACT UPON THE BIOLOGICAL WASTEWATER TREATMENT FACILITY
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Mirela STOENICÃ, Vasile LAVRIC
The recycle and purge ratios are responsible for the two of the main time scales of the wastewater treatment facility, the residence time of the biological reactors, and the doubling time of the microorganisms accountable for the biodegradation of substrates. The effects of threshold imposed to...
MICROBIAL PRODUCTS AS NATURAL ALTERNATIVE TO FERTILISERS: ISOLATION AND CHARACTERISATION OF NITROGEN FIXING BACTERIA
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Ãva TAMÃS, Gyöngyvér MARA, Ãva LASLO, Ãva GYÃRGY, István MÃTHÃ, Beáta ÃBRAHÃM, Szabolcs LÃNYI
The nitrogen fixing bacteria have stimulating effect on the plant, they are able to fix the nitrogen in symbiosis with leguminous plants using the nitrogenase enzyme complex14. The isolation of the strains was made from the soil on selective media, and the strains were characterised through...
A BANK ROBBERY – A PUZZLE SOLVED BY FORENSIC CHEMISTRY EXAMINATION
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Maria Georgeta STOIAN, Elena GALAN, Georgeta ANDREESCU, Gheorghe NECHIFOR
Forensic chemistry performs qualitative and quantitative analysis of chemicals found on people, various objects, or in solutions. The final result of the forensic scientist’s work, the expert report, has a direct influence on the fate of given individuals. This burden implies a high...
ETHYLENEDIAMINE FUNCTIONALIZATION EFFECT ON THE THERMO-MECHANICAL PROPERTIES OF EPOXY NANOCOMPOSITES REINFORCED WITH MULTIWALL CARBON NANOTUBES
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Celina-Maria DAMIAN, Andreea Mãdãlina PANDELE, Horia IOVU
Functionalization of multiwalled carbon nanotubes (MWNTs) may improve the thermal and mechanical properties of the epoxy composites in which they are embedded as reinforcing agents. Amine groups were chosen to functionalize the carboxylated MWNTs due to their potential to form bonds with the...
FORECASTING THE SORPTION OF PHOSPHATES IN SOIL WITH ARTIFICIAL NEURAL NETWORKS
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Ecaterina DIACONU, Oanamari Daniela ORBULEÃ, Alexandra Raluca MIRON, Cristina MODROGAN
In this study, we are concerned with the prediction of adsorbed amount of phosphate and the sorption rate on soil particles in a chernozem from agricultural zone. Artificial Neural Networks (ANNs) have been used for modeling the behavior of phosphate (P) pollutant. The findings of numerous...
INFLUENCE OF MECHANICAL ACTIVATION ON THE KINETICS OF NON FERROUS METAL SULPHIDES OXIDATION
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Silviana ONISEI, Petru MOLDOVAN, Luminiþa MARA, Vasile PREDICA, Cornelia LUPU
The paper presents experimental research results on a new concept of oxidation in aqueous medium (solution of sodium carbonate) of copper sulphide concentrate in autoclave under air pressure in the temperature range 100 to 135 oC for 5 h, partial air pressure 5 atm in the presence of 30% excess...
MECHANICAL BEHAVIOUR COMPARISON BETWEEN UN-PROCESSED AND ECAP (Equal Channel Angular Pressing) PROCESSED 6063-T835 ALUMINUM ALLOY
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Vasile Dãnuþ COJOCARU, Doina RÃDUCANU, Nicolae ªERBAN, Ion CINCA, Rami ªABAN
Equal Channel Angular Pressing (ECAP) is a very interesting method for modifying microstructure in producing ultra fine grained materials (UFG) and nanomaterials (NM). It consists of pressing test samples through a die containing two channels, equal in cross section and intersecting at an angle...
MORPHOLOGY OF THE METALLIC TIN ALLOTROPIC TRANSFORMATION AND IMPURITIES ROLE IN STRUCTURAL STABILITY ASSURANCE
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Maria FAUR, Wilhelm KAPPEL, Brânduºa GHIBAN, Elena ENESCU, Magdalena LUNGU
The present paper presents the results concerning the morphology by electron microscopy and the way in which temperature and impurities contents may influence the nucleation and growth of the  Sn. Tin is a metal with polymorphic phenomenon, with great difference between two allotropic...
SIMULATION DE RÃSISTENCE À LA TRACTION ET COMPRESSION DANS UN COMPOSITE MACROMOLÃCULAIRE
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Maria Cristiana ENESCU
Nanoparticles such as silica have been widely used for reinforcing polymer systems. Incorporation of nanoparticles in the manufacture of nanocomposite polymer matrix provides a method for obtaining hybrid materials that integrate the characteristics of each component in the final material...
MECHANIC VIBRATIONS GENERATION SYSTEM AND EFFECT ON THE CASTING ALLOYS SOLIDIFICATION PROCESS
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Crenguþa Manuela PÃRVULESCU, Constantin BRATU
The paper discusses the possibility to apply a treatment to the liquid metallic materials and their crystallization under the influence of mechanical vibrations. To demonstrate the existence of the effect of the mechanic vibrations we tried to make them evident by solving two problems: 1 - by...
SELECTIVE RECOVERY OF GOLD FROM HYDROCHLORIC SOLUTIONS WITH AMBERLITE XAD-7 ION-EXCHANGE RESIN
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Antoneta Filcenco – OLTEANU, Tãnase DOBRE, Rozalia RÃDULESCU, Eugenia PANÃURU, Rãzvan PANÃURU
The paper presents the results obtained in the selective recovery of gold from hydrochloric solutions using Amberlite XAD-7 ion-exchange resin. Experimental tests were conducted on real solutions obtained following selective leaching of gold from different metallurgical wastes, through wet...
THE INCLUSION STUDY AND THE DETERMINATION OF ALUMINUM AND INSOLUBLE CALCIUM IN AIRCRAFT STEEL SAMPLES
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Mariana BAHRIM
The present paper presents the data obtained as a result of the determination of the soluble/insoluble part of Ca and Al and the study of Al and Ca inclusions in aircraft steel samples When analyzing the samples, I used the Spark-Dat method and I analyzed the inclusion with the help of the 21...