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The paper presents the development of a cross-ply composite material reinforced with carbon fibers and epoxy matrix (CFRP). Specimens cut from composite plate have been tested in tensile, using a testing machine with hydraulic grips, assisted by full-field strain measurements equipment. Using tensile tests and ultrasounds technique, were determined the nine elastic characteristics of the orthotropic material. During tensile test, at a certain level of stress, inside the specimen, small cracks appear. These cracks become more numerous and larger with increasing of stress. A portion of a specimen without cracks and with cracks respectively, subjected to tensile, were simulated by Finite Elements Analysis (FEA). For this analysis, the composite material was considered homogeneous and orthotropic. The simulation of cracks presented inside the specimens at different stress levels has been realized using X-ray pictures. Based on the FEA determinations, the stress state in the vicinity of the cracks was determined.

In the paper, I have brought in a method whereby a body with rheological behaviour is associated to a dynamic-equivalent Kelvin model. The equalization is made so that the forced vibration caused for Kelvin model by a harmonic external impulse is identical to the forced vibration caused in the case of the studied rheological model. It was experimentally determined the elasticity modulus and damping factor for samples with Dammar bio-matrix, reinforced with silk, flax or hemp fabric. Modifying samples dimensions, It was studied the vibrations frequency effect on the studied mechanical properties.

The aim of this research is to develop plastic pyrotechnic compositions with a high level of moldability while maintaining safety and performance features specific to usual plastic bonded pyrotechnic compositions. In this view, theoretical and experimental studies have been performed in order to determine the characteristics of three new plastic pyrotechnic compositions and to establish their agreement with energetic materials safety and performance essential principles. These formulations have been designed to accomplish special requirements, such as processing performances, i.e. good malleability for hand packing or molding at room temperature, and pyrotechnic effects, i.e. illuminating or smoke signaling.

Removable partial dentures (PDs) are an affordable and effective treatment option in patients with partial edentations.This aim of this study is to evaluate the differences, in the terms of patient’s compliance, in restoration of partial edentations through three types of PDs, achieved of Meliodent-Kulzer acrylic resin, Valplast® polyamide resin, respectively of BioDentaplast-Bredent acetal resin. Investigations were carried out on 78 patients (3 groups of 26 patients), to which were performed 101 PDs (35 of Meliodent-Kulzer, 33 of polyamide Valplast®, respectively 33 of BioDentaplast-Bredent) and after the accommodation period with the dentures, six assays of compliance have been conducted. The results of the research have demonstrated that PDs made of flexible materials were far more favourable than those made of Meliodent acrylic resin, and PDs with BioDentaplast framework presented the best impact. The ascertained differences are relevant in the treatment of partial edentation, for choice of the best option for one of these three polymeric denture base materials.

This paper presents the results of the research work performed by the authors aiming at highlighting and quantifying the reinforcement effects (restoring of the mechanical strength) on transmission pipelines, generated by applying composite material sleeves in the areas in which the steel pipes of these lines have local surface defects (metal loss – like flaws). The models proposed to that purpose have been confirmed by performing some experimental programs, the first one consisting of the examination of the behaviour of some full-scale steel pipe specimens, with metal loss – like flaws (made by machining), on which reinforcing wraps made of composite material have been applied (with polymeric matrix and fiberglass fabric), subjected to internal pressure loading, up to bursting, and the second one aiming at the determination of the state of stress and strain in the pipelines on which reinforcing wraps made of composite material have been applied and which are subjected to internal pressure loading, in the elastic range. The items discussed and the results presented in the paper are mainly useful for the development and qualification of the composite materials repair systems for the transmission pipelines, according to the requirements of the standards ASME-PCC2 and ISO 24817.

The growing utilisation of carbon materials increases the waste generation. Therefore, the development of new composites using recycled carbon fiber reinforced polymer (rCFRP) within the present study was driven by environmental and economic factors. Six configurations of new polymeric matrix composites were developed and evaluated by mechanical tests (flexural, compression and interlaminar stress), microscopic and thermal analysis. Four configurations of composites were obtained by filling the matrix with rCFRP powder and fibrous elements mixture, the reinforcement phase being produced by grinding carbon fiber reinforced polymer (CFRP) waste. The new composite configurations showed an increase in mechanical properties with rising the reinforcement fraction. The samples analyzed by stereomicroscopy reveled a fairly homogeneous distribution of the reinforcement in the matrix for 5%wt. up to 30%wt., whereas thermal analysis showed no significant changes in the glass transition temperatures of developed materials. Two configurations of composites were obtained by chemical etching of the matrix and recovering carbon fiber woven, used subsequently as reinforcement phase for new composite configurations. The same method was used for determining the volume fraction of CFRP composite constituents. Initial results demonstrate that recycled carbon remains a highly satisfactory engineering material. These results showed that recycled FRP composites can be used to develop new less demanding composite materials or improve some properties of FRP composites.

The textile polymeric composites define a class of advanced materials, utilising fabrics as reinforcement. The geometry, as well as the structure of textile reinforced polymeric composites, are much more complex than that of composites reinforced with unidirectional fibres. The mechanical properties of textile reinforced composites are influenced by several parameters such as fibre material, the internal geometry of the fabric, number of counts, size of gap between adjacent yarns, height of woven layer, undulation and thickness of the composite lamina. Each of these factors can influence the structural behaviour and can be modelled based on its specific length scale. This paper is focused on the modelling procedures of the in-plane stiffness characteristics, specific to satin reinforced laminated composites. The method used is a compromise between the continuous and pure discrete approaches and it is associated with a mesoscopic analysis of the repetitive unit cell (RUC). The elastic properties of the textile reinforced polyester composite, using S glass fibre, arranged in satin reinforcement, are determined and analysed taking into account the variation of two characteristic geometric parameters, namely the width and the height of the reinforcing tow.

This paper reports the fabrication of spherical particles developed as bone tissue regenerative biomaterials. Inspired by the extracellular matrix of hard tissues, the particles were generated through the mineral loading of a macromolecular matrix consisting in a bicomponent hydrogel (interpenetrated polymer networks based on gelatin and alginate). The study describes the effects of the peptide-polysaccharide ratio on the morpho-structural features, water affinity, and interaction with MG-63 osteoblast-like cells.

The management of laryngeal trauma represents one of the most challenging problems for an ENT surgeon. The alternatives vary from a “wait and see” approach to extensive and immediate reconstructive interventions, but in all cases the risk of laryngeal stenosis remains high. This translates into a poor quality of life for the patients and increased costs for the health system. The use of a resorbable plate for the reconstruction of the affected cricoid has the advantages of requiring a single intervention and enabling the patient to return to his normal activities in a shorter period of time. It is why we present this method of approach, which can be a viable alternative in managing these difficult cases.

The aim of this study was to point out the effect of elaboration parameters on the structure and electrochemical stability of a bioinspired hybrid film chitosan with hydroxiapatite (HAp) on Ti50%Zr alloy. The new hybrid films based on chitosan and hydroxiapatite were elaborated electrochemically using various ratio between components and different temperature and time of electrodeposition. The electrodeposition electrolye was a mixture of (NH4)2HPO4 , Ca(NO3)2 and chitosan. The structure was identified by Fourier transform infrared (FTIR) spectroscopy, and the morphology associated with elemental analysis were evaluated by scanning electronic microscopy (SEM) and X ray diffraction. Surface characterization was completed with contact angle measurements. Electrochemical tests in physiological solution (NaCl 0.9%) potentiodinamic polarization curves (tafel plots procedures). Based on experimental data we can conclude that the hybrid coating with higher HAp concentration is the most stable.