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The main purpose of this study is to evaluate three different adhesiveprotocols between two composites. We used 60 composite specimens (Kerr’s Herculite XRV Ultra), randomly divided into 3 equal experimental groups, in which adhesion was performed using different protocols: Group 1 (n= 20) surface preparation with a 1.4 mm cylindrical diamond bur (Kerr Dental, FG503C-5) + etch and rinse technique in 2 steps; Group 2 (n= 20) surface preparation with a 1.4 mm cylindrical diamond bur (Kerr Dental, FG503C-5) + Al2O3 (Zhermack Dental) sandblasting + etch and rinse technique in 2 steps; Group 3 (n= 20) surface preparation with a 1.4 mm cylindrical diamond bur (Kerr Dental, FG503C-5) + glycine (EMS) sandblasting + etch and rinse technique in 2 steps. Adhesion assessment was made by measuring tensile strength with a universal testing machine, the INSTRON 3343 (Instron®, USA). At the end, the results were statistically compared using the ANOVA test. Group 3 (glycine protocol) had the greatest values in terms of tensile strength.

The wastes from polyethylene terephthalate (PET) packaging can be turned into armatures for concrete used in the transports infrastructure (roads with rigid concrete structure, pedestrian and concrete pavements and borders), as well as in the construction of safety elements (support walls, bulwark foundations). This experimental research was meant to create dispersed reinforced concrete with armatures from polyethylene waste, originated from the recycling programmes of PET–type packaging. The experimental programme was aimed at constructing some samples of dispersed reinforced concrete from recycled material coming from polyethylene terephthalate (PET) packaging wastes, their testing to the compressive strength and the comparison of results with the characteristics of the standardised samples of concrete (class C30/37). All the reinforcements used in this work to consolidate the dispersed reinforced concrete type were made from a mix of polyethylene terephthalate (PET) packages, of different types and characteristics, which are found daily in supermarkets and which then reach waste. The choice of a mix of polyethylene terephthalate (PET) packaging was chosen in order to render the general recycling of these types of materials as good as possible.

This paper is the second part of a study regarding the biomechanical behaviour of mandibular bone in the context of different periodontal splinting systems, occlusal forces and load distributions. Electric resistive tensometry method was used to measure the strains developed in mandibular bone replica. The tests were carried out on six mandibular acrylic models, each with 8 natural teeth. The experimental groups were defined corresponding to the bone condition and splint type: normal height bone; bone resorption without splint; bone resorption and wire-composite splint; bone resorption and polyethylene fiber-reinforced composite splint. Each sample was subjected to three similar loading cycles, the force being applied successively on four incisors, two central incisors and canines, and the specific deformation values were read for four loading forces: 30 N, 50 N, 100 N and 150 N. In case of bone loss, the bone deformations are up to 110%. Periodontal splinting redistribute forces, reducing incisors bone strains associated with a slight increase in canine bone strains.

Woven fiber reinforced concrete is a material, which contains various quantities of polymer materials in composition, in addition to the conventional components of an ordinary concrete (mineral binder – cement, aggregates, water and additives). The present work refers to the concrete in which the reinforcement is made of polymeric materials (polyethylene terephthalate), originated from the recycling programs of PET–type packaging. The experimental program was aimed at constructing some samples of woven fiber reinforced concrete from recycled material coming from PET packaging wastes, their testing to the compression demands and the comparison of results with the characteristics of the standardized samples of concrete (class C30/37). Based on a sufficient number of determinations, certain correlations can be established between the compressive strength of the concrete at 28 days depending on the dosage of components (aggregate, binder, and reinforcement), water / cement ratio, reinforcement volume, etc., essential parameters from a compositional point of view. These correlations, customized by cement type and strength class, are very important to determine – with approximation – to what dosage of components (aggregate, binder, reinforcement) the respective level of compressive strength of concrete is obtained.

Simulating the biomechanical behavior of a reconstruction using the finite element analysis method is a modern method necessary before the practical stage of a research, thus enabling the precise shaping of certain trajectories in the approach of certain directions of practical applicability, as well as obtaining final results with relevant data (results coupled with experimental models that reiterate the clinical situation that will be later analyzed).

The present paper is focused on evaluating the mechanical characterization of dicyclopentadiene (DCPD) and 5-ethylidene-2-norbornene (ENB) healing systems synthetized by in-situ polymerisation. Both healing systems were embedded in glass fibre reinforced polymer (GFRP) composite and subjected to three-point bending test regime. Microstructural and FT-IR analysis showed the formation of microcapsules and a successful integration in the composite material. To observe the influence of temperature variation, some specimens were exposed to thermal cycling (-20oC to +100oC) for 12 hours and tested in the same conditions. It was observed that the addition of microcapsules in the composite material decreased its mechanical properties by 8% and 10% for DCPD system and ENB system respectively. Thermal cycling suggested a drop of 24% on bending strength for DCPD system and 17% for ENB. Resting after 24 hours showed a healing recovery of 74% for DCPD healing system and of 97% for ENB system.

The main objective of this study was to investigate thermoplastic materials design and fabrication processes for manufacturing composite impeller blades. Polyurethane (Necuron) and ABS (3D printed) thermoplastics were chosen due to their good mechanical properties, tooling applications, easy manufacturing and lifetime. For both thermoplastics, workability and hardness tests were performed, as well as microstructural and mechanical characterization evaluating their physical and mechanical properties. A 1:2.5 scale mould was designed and milled from Necuron N651 and N1001 and used for manufacturing of 1:2.5 scale composite impeller blades. Also, 1:1 scale ABS mould components were 3D printed and used to manufacture full scale composite impeller blades. All composite impeller presented good surface quality and tolerances with respect to CAD design, thus answering to requirements related to composite processing

The aim of our study was to compare the fracture resistance of teeth presenting non-carious cervical lesions restored with different types of esthetic composite materials. 20 extracted unspoiled maxillary first molars were mechanically cleaned and immersed in saline solution containing 0.1% thymol at 4°C for a period of 48 hours. Cervical cavities with a cervical-occlusal diameter of 2 mm and a mesial-distal diameter of 3mm were filled with ormocer, flow nano-composite, nano-composite and compomer. Fracture resistance was tested with a universal loading machine (Lloyd Instruments), with a maximum force of 5 kN and a crosshead speed of 1.0 mm/min; the authors used NEXYGEN Data Analysis Software and ANOVA method. For the group A (commercial grade ormocer), the smallest load that determined the sample failure was 650 N and the highest load was 1050 N, the mean value being 858 N ± 150.89 N. For the group B (commercial grade flow nano-composite), the smallest load is 530 N, the highest load is 800 N, mean value being 654 N ± 112.6 N. For the group C (commercial grade nano-composite), the smallest load is 680 N, the highest load is 1200 N, mean value being 926 N ± 209.35 N. For the group D (commercial grade compomer), the smallest load is 1100 N, highest load is 1250N, mean value being 1180 N ± 62.04 N. A p value of 0.000311 (p[0.05) shows that there are significant differences between the four groups. Conclusions. The best fracture resistance of teeth presenting non-carious cervical lesions, restored with different types of esthetic composite materials is assured by the compomer, followed by the nano-composite, which proved to be superior to ormocer. The flow nano-composite gives the lowest fracture resistance.

The global concern in wastewater recycling technologies has grown steadily since the early 1990s and is gaining more and more interest due to the increase in water supply needs. This growing need affects many global regions and leads to an increase in the strictness of environmental regulation, both in developing and developed countries. Many countries, cities and local governments are trying to recycle wastewater as a potential source of water for various uses, especially non-potable uses, such as land use, water for toilets and industrial processes. Analysts and statisticians around the world are trying to provide a perspective on an industry that is poised to see significant developments in the next decade. The researches summarize the experimental tests carried out using a new cellulosic adsorbent material to purify the wastewater resulted from the industrial processes for leather manufacturing. The study highlights the influence of the pH used for the wastewater depollution. The tracked and measured parameters include the pH, chemical oxygen demand, biochemical oxygen demand, total suspended solids, ammoniac nitrogen, organic compounds extractable in organic solvents and the solid residue adsorbed by the material. The obtained values were discussed in concordance with the national legislation for wastewater treatment and the levels accepted for releasing the used water in the surface waters.

This study aims to find the most effective method in terms of clinical working time when applying fibreglass splints in the lower frontal group, depending on the type of composite material used. We have selected a group of 30 patients, aged between 50 and 70, with an average age of 57, in the interval March 2016 – June2017. These patients received immobilisations as part of their periodontal treatment, using a system consisting of fibreglass and three different types of composites. The shortest work time was obtained when using the Grandioso heavy flow composite, the next closest time being obtained with Gaenial flow universal. Our study indicated that the highly viscous flow composite resins offers the shortest clinical working time out of all tested materials.