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Full denture casting currently represents a technological alternative. The casting system we tested usually uses reversible hydrocolloids for investing wax patterns. Besides the system’s own advantages, the authors also noticed certain errors consecutive to casting, materialized in lack of substance and the development of porosities on the mucosal facets of the complete denture bases. Keywords: casting, full dentures, errors

The aim of the experimental study described in this paper was Lamb wave method evaluation for damage/defects detection of epoxi/glass composites. Can be used piezoelectric transducers - actuator/sensor - glued on the surface of investigated composite, using transmission mode. The chosen control parameter was the sensor signal attenuation because of defects that exists in examinated samples. The proposed monitoring system was efficiently in the detection of damage/defects such as holes, allowing for damage/defect size estimation. Keywords: composites damages detection, Lamb wave

Ultrasonic waveform is one of the parameters that characterize a material.Thus, in this paper, the authors aim to visualize and characterize different waveforms of a POLYPROPENE FOIL F-401. The experiment is made with non contact transducers (the resonance frequency is 50 MHz) by applying the method through transmission. There are determined the acoustical and spectral parameters such as the propagation velocity, the time of the flight of the ultrasound, the pulse width, the bandwidth, the peak frequency and its amplitude. The waveform without the sample beeing placed between the transducers (transmitter-receiver) is considered to be the reference. Then, the sample is placed between the transducers at different distances from the transmitter. These waveforms are compared and analysed relative to the reference. Keywords:ultrasounds, non-contact transducers, polymers, ultrasounds waveforms

The objective of this study is to compare the results obtained while determining the amount of residual monomer in three samples of acrylic resin in the first 24 hours after getting done the prostheses in the dental lab with the results of patch-tests performed on three subjects, after they have worn dentures for three months. Keywords: patch-test, acrylic resin, residual monomer, allergenic potential

The epoxy resin EPO 99B, known under the name REZOLIN, is one of the main materials used in manufacturing/modeling the axial runner of hydraulic machines. The simplest device of this kind is the inducer employed to reduce the cavitation intensity of the main pump impeller. The geometry is determined from hydrodynamic conditions, is a very complex one and is subjected to dynamic mechanical stress (vibrations). As a result of those conditions the resin must have good mechanical and technological qualities. It was realized at SC Elba SA Timisoara, and is made from a mixture between the resin H9951 and a fortifier. The obtained inducer runners have been tested in air at the Hydraulic Machinery Laboratory of Timisoara Polytechnic University, and supplementary the basic material was tasted to cavitation erosion resistance. As a result, our work takes into considerations both the impeller hydrodynamic performances and the behaviour of the manufacturing material (resin EPO 99 B) to cavitation erosion. Key words: epoxy resin, cavitation erosion of plastic material, inducer runner performances

This paper presents some morphological properties of polyamide 6 thin films obtained by spin-coating method. These properties were investigated by scanning electron microscopy and atomic force microscopy. It results that the thin film thickness is influenced both by rotation speed and solution concentration. Finally, some aspects between morphological and optical properties (structural colours) were considered. Key words: polyamide thin films, spin-coating method, scanning and atomic force microscopy, structural

Poly(betaine)s based on poly(N-vinylimidazole) (PNVI) and poly(4-vinylpyridine) (P4VP), namely poly(carboxybetaine)s with one (PNVIB-1 and P4VPB-1) and two (PNVIB-2 and P4VPB-2) methylene groups between the opposite charges were prepared. Poly(betaine)s represent high dipolar materials with wide spectrum of unique and specific properties. Some of such properties are shown in this paper. Thus, the PNVIB-1 and P4VPB-1 are insoluble in water but the addition of salts promotes their solubility, whereas PNVIB-2 and P4VPB-2 are soluble both water and aqueous solution of salts as well as in methanol. Also, for all the polybetaines one of the most interesting properties in solid state is the formation of homogeneous blends with some inorganic salts in equimolecular amounts, they being a new type of organic-inorganic hybrid materials. Keywords: poly(carboxybetaine)s, anti-polyelectrolyte behaviour, poly(zwitterions), organic-inorganic hybrids

A new type of polyurethane metal-complex was prepared by incorporating the transition metal ions such as copper (II), cobalt (II) and nickel (II), into polyazomethine-urethane-urea, containing functional groups. Polyazomethine-urethane-urea (PAMU) was synthesized from 5,5’-methylene-bissalicylaldehyde (MBS) by reaction with an urethane prepolymer based on polyethylene adipate diol (PEA), hexamethylene diisocyanate (HDI) and ethylene diamine (EDA), in DMF as solvent, using 0.5 wt % dibutyltindilaurate (DBDTL) as catalyst. The polymeric Schiff base was converted to the chelates of the metal salts. This complex was performed by mixing of the polyazomethine-urethane-urea, containing functional groups, with the metal salts in DMF as solvent. The polyurethane metal-complexes were characterized by FT-IR spectroscopy and elemental analysis. The polymer property investigated was their thermal stability which was studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The aim of this work is to present a general idea of the various methods of preparation, properties, and applications of metal-containing polyurethanes. Keywords: polyazomethine-urethane-urea, chelate polymers, metal-polymer complex

The applications of membranes and membrane processes in advanced separations from biotechnology have gained lately a great importance determining their inclusion among the top technologies. This paper presents an original variant for preparation of some affinity membranes from acylated polysulphone and brominated polyphenileneoxide, with immobilized starch as affinity ligand for biospecific separations. Keywords: membranes, phase inversion, affinity ultrafiltration , ligand

The aim of this paper is to present a proper methodology for obtaining active mould parts. The originality of the paper consists in the fact that building these active objects starts from some distinctive marks (machine parts) for which there’s no technical documentation. Using reverse engineering procedures (scanning and reconstruction) for polymeric material machine parts and rapid prototyping procedures by material sampling, we will finally obtain both the wanted distinctive mark and its active elements. Keywords: reverse engineering, rapid prototyping, polymeric material, mould