Arhivă — Seria B

1

INFLUENCE OF THE SURFACE TREATMENT WITH OXALIC ACID ON THE BEHAVIOUR OF A PORTLAND CEMENT TO ACID CORROSION

Ion TEOREANU, Alice POP Mariana COARNA, Daniela NASTAC

From the economical and safety in exploitation points of view, the knowledge of the environment factors and the characterization of their aggressiveness are essential conditions for an appropriate design of durable cements and concretes. \r\nThe paper presents the effects of the surface treatment with oxalic acid of …

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2

PROPERTIES OF BLENDED CEMENTS WITH LIMESTONE FILLER AND FLY ASH CONTENT

Maria GEORGESCU, Nastasia SACA

This paper brings information regarding the evolution of physical mechanical properties of some blended cements with limestone content, fly ash content and of some composite Portland cements (with limestone and fly ash). Determinations concerning setting time, mechanical strengths and behavior in different acid solutio…

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3

EVALUATION OF THE EFFECT OF SOME MINERAL ADDITIONS ON THE BURNABILITY OF RAW MIX IN CEMENT PRODUCTION

Alina BÃDÃNOIU, Jenica PACEAGIU, Georgeta VOICU

The present paper deals with the influence of different types of mineralizer (oxides, fluorides and their mixtures) on the processes that take place at the burning of raw mix at temperatures below the eutectic temperature - assessed by thermal analysis (DTA, TG). Additional information about the burnability of the ind…

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4

ORGANIC-INORGANIC MEMBRANE MATERIALS

Florina Daniela BÃLÃCIANU, Radu BARTOª, Aurelia Cristina NECHIFOR

The synthesis of mesoporous silica with controlled nanostructures and morphologies has received much attention owing to their potential applications in catalysis, separation, drug delivery and nanocomposites. Introducing organic groups in the mesoporous materials has attracted attention because the organic group has ma…

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5

ANALYSIS OF SOL EVOLUTION IN SOL-GEL SYNTHESIS BY USE OF RHEOLOGICAL MEASUREMENTS

Tãnase DOBRE, Oana Cristina PÂRVULESCU, Gustav IAVORSCHI, Anicuþa STOICA, Marta STROESCU

The paper focuses on characterization of barium titanate sol-gel synthesis by acetate method, starting from barium acetate and titanium isopropoxide as main precursors. The formed sol becomes more viscous and evolves towards a gel structure by addition of water. This is due to an enhancement of hydrolysis and polyconde…

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6

SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL ACTIVITY OF PHENOL-2,6-PYRIDINEDIAMIDE COMPLEXES WITH Fe(III) AND Mo(VI)

Mihaela ALEXIE, Florina DUMITRU, Denisa MÂNZU, Ticuþa NEGREANU-PÂRJOL, Cornelia GURAN

The paper is focused on the synthesis and characterization of a new ligand (amide-phenolate) N2,N6-bis(4-hydroxyphenyl)pyridine–2,6–dicarboxamide, L, that may be used as biomimetic analogue of Fe(III) or Mo(VI)-siderophores. Complex compounds of this ligand with Fe(III) or Mo(VI) have been obtained for a metal-ligand …

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7

CYCLIC VOLTAMMETRY SIMULATION USING ORTHOGONAL COLLOCATION: COMPARISON WITH EXPERIMENTAL DATA AND MEASURING THE ELECTROCHEMICAL RATE CONSTANT

Dan DRAGU, Mihai BUDA, Teodor VIªAN

The electrochemical rate constant for the redox couple Co(bpy)32+/3+ was estimated using the Nicholson method. The value was checked by digital simulation of a cyclic voltammetry experiment. The simulation procedure is based on the orthogonal collocation method and includes the uncompensated ohmic drop during experimen…

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8

COLORANTS WITH MIXT NAPHTHOQUINONE-AZOMETHINE CROMOPHORE-SYNTHESIS, CHARACTERIZATION AND IN VITRO TOXICITY ANALYSIS

Paula - Roxana IONESCU - MOCANU, Gheorghe HUBCÃ, Cristian BOSCORNEA, Stefan TOMAS, Liliana ISFAN, Anca - Nicoleta MOCANU

The paper presents the synthesis of some new original compounds based on a compact condensed heterocyclic aldehyde obtained by reacting 2,3-dichloro-1,4-naphthoquinone and its 5- substituted derivatives with salicylaldehyde, followed by the condensation of the resulting products with different aromatic amines, leading…

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9

CONTRIBUTIONS TO THE NITRIDING CHEMICAL TREATMENT OF A NITRALLOY STEEL

Marina Eraclia BÃNICÃ, Gabriel George GRIGORESCU

The experimental results regarding the effects of the variation of the thermal and time parameters of the gaseous nitriding process upon the kinetics of layer formation and of the properties reflected by the macrohardness (HV5kgf ) are presented. \r\nThe material used for these experiments was the nitralloy steel wi…

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10

PRECONDITIONING OF ELECTRICALLY MELTED GREY CAST IRONS

Mihai CHIªAMERA, Iulian RIPOªAN, Stelian STAN, Chris ECOB, Geir GRASMO, David WILKINSON

Laboratory research has been conducted to investigate the effect of strong deoxidizing elements such as Al or/and Zr in preconditioning of electrically melted un-inoculated and inoculated grey cast irons. Both Al and Zr sustain the A-type graphite formation with a lower degree of eutectic undercooling and free carbides…

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11

CARACTERIZATION OF THE STRUCTURE AND CHEMISTRY OF OPTICAL FIBER

Daniela Beatrice COªMELEAÞÃ, Simona ZAMFIR

The experimental characterizations carried out in this paper allowed the evaluation of the structure and properties of SiO2-based optical fibers for two categories of optical fibers: mono-mode and multi-mode optical fibers. The emission spectra of X radiations and the quantitative analysis for the core, cover and the…

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12

THE INFLUENCE OF THE LASER SURFACE MELTING PARAMETERS (LSM) ON THE STRUCTURE AND MICROHARDNESS OF THE 316L AUSTENITIC STAINLESS STEEL

Raluca Ioana ZAMFIR

The improvement of the performances of the austenitic stainless steels by using a laser heat treatment (LSM) started as a result of the field increasing of applications and necessity of improving the surface characteristics of these materials. LSM presents interest from industrial view point especially as a material th…

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13

MICROSTRUCTURAL CHARACTERIZATION OF AA - 7050 ALLOY SLABS (PART I)

Nicole PANAIT, Mariana CIURDAª, Robert STEPHAN

The microstructure of 7050 DC slabs cast in Wagstaff installation, in different zones of the transverse section of the slabs is presented.By electron microscopy (SEM,EDS) the morphologies and composition of the intergrain phases which contains Al,Mg, Cu, Zn and intragrain phase with Mg and Zn content was put in evidenc…

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