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In this research, the thermal performance of the hybrid composites with modified epoxy matrix was investigated. The results were compared with those presented by the hybrid composites with homogeneous epoxy matrix. For understand the effects of the replacement of lower specific density glass fabric by higher specific density glass fabric, the thermal properties of the hybrid epoxy composites were determined by comparison to the thermal results of composites reinforced with lower specific density glass fabric with those of the hybrid epoxy materials reinforced with higher specific density glass fabric. Also, the effects on the specific heat and thermal expansion coefficient of the used fabric types in outer sheets of the composites were studied.

This paper presents a comparative study with respect to the behavior of some painting materials, used mainly for decorative and protective industrial applications, exposed to a controlled accelerated ageing process by using thermal storage and successive thermal cycles. The evaluation of the structural changes, as well as those concerning the dielectric loss were carried out in a comparative manner, on the initial samples, before any exposure to thermal stresses and during the ongoing process of the thermal treatments applied. As analysis techniques coupled thermal analysis and dielectric impedance spectroscopy have been used. It was found that there is a clear correlation between the structural changes of the investigated materials, particularly in the case of the epoxy materials subjected to the applied thermal treatments and the evolution of the dielectric losses in the material. As a result of these investigations, one may determine the characteristic acceptable zones for the thermal stresses (up to 1300 h of storage and 1500 thermal cycles), anything above these boundaries leading to strong increases in the dielectric losses and hence the deterioration of the materials rendered unfit to be used for the intended purpose.

The objective of this in-vitro study was to compare the accuracy, defined as trueness and precision, of two intraoral digital scanners that use different capturing techniques. An experimental reference object consisting of a die was manufactured from a PMMA resin. The reference object was digitized with an industrial CT and was scanned 15 times with each scanner. In order to asses trueness, comparisons were made with the virtual reference model, and for fidelity, the first scan in the series was compared with the following scans. For both fidelity and trueness, the F test and T tests demonstrate that there is a statistically significant difference between the scanners.

In this paper, a model of a composite plate with a central elliptical cut-out and with an initial fissure was subjected to a tension load in the finite element method (FEM) software Abaqus to observe the propagation of that crack during a certain amount of time that elapsed in the FEM analysis. Due to symmetry, only half of the plate was modeled, as a shell, and the extended finite element method (XFEM) was used for the crack. The material properties that were assigned to the plate were taken from the database of the Ansys Mechanical software. In the vicinity of the crack a finer mesh was applied to be able to better observe the evolution of the fissure and the changes of the Von Misses stress graphs for each time step of the analysis.

In this paper we analyze the influence of the number of laser pulses on the hardness of the metal. We have shown that the hardness increases with the number of laser pulses due to the increase in the probe surface temperature, especially by increasing the superficial absorption of laser radiation. Optical microscopy was analyzed by the metallographic aspects of the target in OLT 65, Al, Cu, laser irradiated.

Laryngeal stenosis represents a serious and challenging condition in the field of otorhinolaryngology. The management of laryngeal stenosis is performed in multiple stages, and numerous surgeries can be necessary to obtain a favorable outcome. We present a specially designed laryngeal stent suitable for patients with stenosis of the larynx, that can be used after CO2 laser resection. The particular shape of the device, the biocompatible material and the autostatic propriety are some important characteristics that improve the tolerability of patients to the stent. The device has multiple advantages that make it a proper therapy method for selected patients with stenosis of the larynx.

3D printing paired with CBCT imaging technology could provide a more individualised approach to orthodontic diagnosis and tratment. The aim of the present study is to asses dimensional differences between the CBCT image and 2 types of 3D printed replicas of an impacted maxillary canine, and to determine whether this method could be used in the future development of customised orthodontic attachments. Ten replicas were printed using the STL file of the impacted canine using two types of resin- five of each, with the same printer. Linear measurements of maximum height, length and width, were made. Mean dimensional erorrs were 0.184 mm and 0.068 mm. The largest discrepancy was in lenght - 0.362 mm. More reasearch is needed, but in this study we obtained printed resin replicas that provide sufficient dimensional accuracy to be used in orthodontics.

In the second part of this series polyelectrolyte multilayer capsules consisting of 6 bilayers of PAH/PSS and one layer of magnetic iron oxide nanoparticles namely D12, were fabricated. These capsules had their inner core removed once the 12 layers had been formed. The properties of the D12 capsules (mean diameter, concentration, dye intake and iron content) were analysed and compared with previously manufactured capsules which had the core dissolved after only 6 layers of coatings namely D6. The new sets of capsules had a greater capsule diameter, higher dye intake into the core and a higher iron oxide loading into the capsule layers.

The aim of this experimental study is to compare the biointegration and tissue response to different surgical mesh types, inserted in various layers of the abdominal wall of Wistar rats. After 30 days, the rats were sacrificed and the meshes were removed en bloc with the subcutaneous tissue, muscular layer and peritoneum. Tissue response (fibrosis, inflammation) was measured using quantitative and semi-quantitative morphometry. We observed that polyethylene terephthalate 3D mesh induces significantly more fibrosis compared to polypropylene mesh and the fibrosis is absent or minimal in case of the control group. Tissue reaction, including fibrosis, is reduced around the polypropylene mesh. We also observed that fibrosis is more intense towards aponeurosis and peritoneum. We can conclude that the 3D mesh shows better biointegration if it is used in proper circumstances. It’s well tolerated by the organism if sutured to the aponeurosis and preferable with monofilament stitches.

ATR / FTIR and DSC techniques have been used to evaluate the thermal stability of some ageing paint materials by heat treatment while immersion in natural ester-based electro-insulating oil. Experimental determinations have highlighted the fact that the investigated paint materials (epoxy resins) have a high oxygen affinity and thus, in closed systems (such as power transformers), they oxidize before coming into contact with the transformer oil. This behavior indicates that the paint layer (suitably chosen) applied on the inside of the transformer vat functions as an antioxidant and results in increasing the thermal stability of the oil.