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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.

Orthodontic appliances usually require the joining of different stainless-steel parts in order to achieve adequate control over tooth movement during the active treatment. The aim of this study was to assess the tensile and shear breaking force of the joints between forty orthodontic bands and forty attachments (buccal tubes), joined by laser and TIG welding, without filler material. For the laser welding technique, we used an XXS Laser (OROTIG) welding unit and for the TIG welding technique, a PUK D2 (LAMPERT) welding unit. The tensile and shear breaking force of the welded joints was determined using the Z010 Zwick/Roell testing machine. The independent-samples t-test showed statistically significant differences between the laser and TIG groups for both the tensile and the shear breaking force tests, the laser welded samples having better mechanical strength than the TIG welded samples. For practical use, under normal loading forces, both techniques are suitable for this particular application in orthodontics. In patients with parafunctional habits, that could develop higher bite forces, the failure of the welded joints might occur if the welding surface is not increased, especially for the TIG welding technique.

Bulk metallic glasses (BMGs) represent a viable alternative for replacing classic materials used in medical devices. This paper presents the research conducted in order to obtain copper based BMGs using two different chemical compositions: Cu48Zr47Al5 and Cu45Zr45Al5Ag5. The samples were obtained by copper mold casting and their structure and properties were investigated using X-Ray diffraction (XRD), differential scanning calorimetry (DSC) and optical microscopy.

The analysis of reinforced polymers is one of the most important sources of information for materials properties designers. In this regard, due to their intrinsic properties, the fabrics play an essential role when they are used as reinforcement elements. The composites properties can be designed by alternating various types of fabrics, by modifying the orientation of every reinforcement layer, by modifying the matrix properties or by choosing the matrix. This study regards the tensile behavior of four fabric reinforced composites with four different epoxy resins as matrix. All the materials have the same reinforcement structure but the matrix is, in each case, another epoxy resin and more two classes of materials had been studied one is containing the natural polymerized matrix materials and the other one the materials that had been thermally treated according to technical sheet of each polymer. The tests were done one year after the materials formation.

Either considering chemical munitions or chemical improvised explosive devices, the armies should be able to counter their effects from two different perspectives: the agent used and the way to disperse it. While the agent to be delivered can be more or less lethal, the real factor that gives efficiency to the attack is the manner the agent is delivered. The state-of-the-art tested garment indicate that current knowledge regarding protective equipment for chemical warfare agents remains very limited. In this context, the present study aimed at the possibility of using the MWCNT-OH-based polyurea-composite material, obtained by our group in a previous study, in the field of protection against hazardous chemicals.