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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.

Painful periapical manifestations are inflammatory responses of periapical connective tissue to pulpal irritants, when the exudative forces become hyperactive. From the point of view of tooth preservation, apical resection is a valuable procedure in avoiding early edentation, as it is a factual surgical method that comes to aid the conservative endodontic therapy. Polymers are chemical compounds (in most cases organic) with large molecules (macromolecules) obtained from the union of a molecular chain (catena) of a large number of monomers usually with identical structural units. In our research we evaluated the resistance to traction 9 test specimens for which the structure was aimed at the improvement of the self-polymerizable acrylic structure by adding sodium maleate co-polymers, namely maleic anhydride, whose structure was linked to the anti-microbial substances, of the thymol type with controlled release, versions with greater resistance, they found clinical applicability on 244 cases. An increased resistance to fracture was registered for the test specimens II, which unites polymer powder together with the sodium maleate co-polymer, in a ratio of 3 to 1 (F = 1030 and max = 37.73), test specimen III, which unites polymer powder together with the co- anhydride maleic polymer, in a ratio of 3 to 1 (F = 950 and max = 37.88), followed by the same combinations to which it was added the care antibacterial substance, thymol. An important role in the long term in the success of the apical resection, in addition to the applied surgical technique, accrues to the retrograde obturation material, which insures an optimal healing at the peri-apical level insuring the bony apposition at this level.

The exhaustive use of light advanced polymer composites into the development of the future high-efficiency long-range commercial aircrafts (primary) structures for increasing strength while decreasing weight for lower fuel consumption and less pollution has attracted great attention in the last decade. In this context, solutions for the integration and joining composites into the aircraft structures metallic sub-assemblies or components, while providing the necessary strength to sustain heavily loaded joints, are urgently required. The paper comes to meet an area of interest for many researchers and large integrators and manufacturers, by presenting several type of metallic join geometrical designs, along with metallic joint part integration solutions into a composite structure directly during production. Performances evaluation of the developed metallic join geometrical designs was performed in static regime by means of „pull-out” compressive tests. The paper focuses on the strength of the hybrid metallic/advanced polymer composites joints. It was concluded that an efficient design of the metallic joint and a proper transition from hybrid to the composite structure can lead to proper integration solutions while assuring safety requirements.

Two types of biocomposite materials are made (original fabrication recipes) containing different resins as base: version A with natural resin and version B with polyester resin. For both of them the reinforcement element is a natural one namely fir needles. The samples are mechanically tested by compression in order to obtain the stress-strain curves and the elasticity longitudinal modulus.

Natural polymers are biodegradable and biocompatible and can be used as carriers of pharmaceutical active compounds, with good results for the enhancement of their stability characteristics.Plant extracts of the Cariophyllaceae family are of great interest due to antioxidant, anti-inflammatory, carminative, anticancer, antibacterial, antifungal, antiviral properties, and more recently, the ability to inhibit intestinal carboxylation and reduce obesity by complex mechanisms.The aim of our study was tocharacterize the Stellaria media aqueous extract from the point of view of total polyphenols (using Folin-Ciocalteu method) and antioxidant capacity, as well as the efficiency of inclusion of Stellaria extract in calcium chloride alginate beads by two different methods. In the same time, the size of alginate microcapsules was investigated along with the released efficiencyfrom the polymeric matrix in different biological fluids.Two different methods for encapsulation of Stellaria media extract were developed in this work, using calcium alginate beads. Encapsulating efficiency shows a better approach within the method in which the extract was in situ encapsulated in “pearls”-shaped beads.

One of the major disadvantages of epoxy resins when they are used to impregnate a fabric or when they are used to obtain laminates is their rigidity that leads in loading conditions to the matrix fracture followed by breaking of fabric due to a shearing mechanism in which the two free parts of the matrix fracture acts as a scissor. During the design of a composite material or structure such behavior of the matrix has to be taken into account and the problem could be solved if the rigidity of the matrix is reduced. The present study is about changing the value of this parameter by using an organic polymer solvent and a thermoplastic polymer to modify the basic properties of an epoxy resin. At this time an analysis of thermal properties of polymer blends is done to determine the effect of solvent and thermoplastic polymer presence inside the epoxy matrix.

The extension of use of light advanced polymer composites from structural parts of an aircraft to all kinds of components of the engine is presently very limited by the knowledge of both technological development process and materials behaviour during service. The paper comes to meet an area of interest for many researchers and large integrators and manufacturers, by presenting the first steps made into the manufacturing of a carbon fiber reinforced composite blades for a centrifugal compressor impeller. An existing metallic reference impeller was redesigned, air flow studies were achieved to establish new design performances, precursors (type, volume fraction, architecture, distribution) were defined for the CFRP (Carbon Fiber Reinforced Polymer), stress analyses were performed on proposed structural materials configurations. Furthermore, the paper award an important section to manufacturing process stages, the manufacturing technology used and first developed trials. It was concluded that an entire impeller CFRP (Carbon Fiber Reinforced Polymer) manufacturing can and shall be the next step of the study, using autoclave technology.