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Structural elements of special industrial constructions can be often subjected to time variable stresses. One of the main stress is the snow action, which is considered to be one of the most severe tests. In the study, the static snow action on a tank cover from a pickling plant on the ArcelorMittal Galaþi platform is analysed. The material structure of the cover is sandwich type with skins made of steel /layered composite and core made of polystyrene foam. The purpose is to determine, by FEM analysis, the deformation mode and the stress condition of the cover under the action of load, for two models of sandwich type structures, steel-polystyrene-steel, respectively composite-polystyrene-composite, with different faces thicknesses and cores. Panels are applied simulative a load of snow of different thickness, the distribution of snow on the surface of the panels being considered uniform in order to determine an optimum combination of faces and core thickness as well weight and economic cost too. Numerical analysis models with finite elements of SHELL 3L sandwich type structures are used.

Urinary incontinence is one of the most common diseases, 25% of women between 18 and 80 years suffer from it. Urinary incontinence can be described as accidently loss of small amounts of urine. The solution involves a surgical procedure, such as sling procedures and bladder neck suspension procedures. The methods of surgical interventions have evolved due to a minimum period of hospitalization (sling, TVT), or performing laparoscopic surgery instead of the classical Burch surgery. Studies reviled that the most effective interventions are those which restore the urethra by retro pubic urethropexy, pubovaginal sling and synthetic mid-urethral slings. This type of surgery has currently the highest success rate (85-90% on 5 years after surgery), and the lowest relapse rate. In our study we obtained the same success rate for the TVT procedure.

The purpose of this in vitro study is to evaluate the marginal percolation-micro leakage by comparing the possible infiltration of ionomer cement filling which was used to restore a class I cavity prepared by classic conventional method – diamond bur versus Er:YAG laser irradiation treatment. Ten molars were included in this study. The molars were random divided in two groups: group 1 - laser treatment and group 2- classic conventional treatments. The teeth were immersed in methylene blue solution for 24 h. Afterwards, the molars were vestibulo-oral sectioned through the centre of each restoration in order to see any signs of marginal percolation. The marginal percolation observed was more significant in conventional preparations group than in laser’s group. The glass ionomer cement remains one of the most adequate restorative materials to be used on deciduous molars when micro infiltration is questionable.

The aim of this study was to evaluate the postoperative effect of one bleaching agent containing 40% peroxide hydrogen on the interface between dental tissues and a microhybrid composite resin bonded with a universal adhesive applied in total-etch and self-etch technique. Standardized Class V restorations were performed in oral surfaces of 40 extracted human molars with the gingival margins placed bellow the cement-enamel junction. For 20 restorations the adhesive was applied with preliminary etching and for the others the adhesive was applied by using the self-etch technique. Half of the samples of each group were bleached using Opalescence Boost in one session 20 minutes-application. The sealing quality of both enamel and cervical margins of the restorations was evaluated using a microleakage test by immersion in 1% methylene blue for 24 hours. The microleakage scores were assessed using an optical microscope and the data were statistically analyzed. No statistical significant differences were recorded between the bleached and control groups and between the study groups according to the etching strategy used for bonding.

The aim of the study was to compare the marginal adaptation of three different resin-based materials used for direct restoration: hybrid composite resin (Gaenial Posterio, GC Corporation), a compomer (Dyract eXtra, Dentsply Sirona), and a giomer (Beautifil II, Shofu Dental) applied at room temperature or after preheated at preheating 50 and 60oC. Class II cavities were prepared on proximal surfaces of extracted teeth and randomly divided in 3 groups according to the material used for restoration. In each group five cavities were restored using the materials at room temperature (subgroup 1), five cavities were restored using preheated materials at 50ºC (subgroup 2), and five cavities were restored using preheated materials at 60ºC (subgroup 3). The teeth were stored in distilled water for 14 days and then were immersed in 2% methylene blue buffered dye solution (pH = 7) for 4 hours. The teeth were transversally cut and the sections were examined using optical microscope (Carl-Zeiss AXIO Imager A1m) at 50x magnification and the dye penetration was evaluated according to 4 scores. Decreased microleakage and fewer gap formation were recorded for all filling materials after they have been heated at 50 or 60oC. Pre-warming of resin-based materials improves the adaptation of these materials to tooth structures.

It is well known that periodontitis causes rapid destruction of gingival and bone tissues. Topical treatments are suitable because the drug can be delivered in a proper and controlled concentration. Metronidazole proved to be efficient for patients with aggressive periodontitis. By this study we aimed to obtain spongious drug delivery systems for local periodontitis treatment based on collagen, strontium renalate and metronidazole. Collagen spongious forms were obtained by lyophilisation of composite gels based on collagen:strontium ranelate (50:50) and different concentrations of metronidazole. The obtained spongious forms were characterized by FT-IR, water up-take, optic microscopy and in vitro release of metronidazole. The prepared matrices absorbed a maximum amount of water after 30 min. The most absorbent sample is the reference one (only collagen) which absorbed about 35% water; the adding of metronidazole decrease the water absorption due to its lipophilic behavior. The samples with strontium are more compact and they absorbed less water than the ones without strontium. Because the samples were not cross-linked they degrade during 24 hours of water absorption process. The drug percentage released was influenced by the drug and strontium ranelate concentrations. The analysis performed sponges indicate that these composites can be useful as drug delivery supports.

The purpose of this research is to establish the technology of 3D printable production on the principle of FDM of gears made of PLA, ABS and PETG mainly. In the paper we present first the dimensional generation and specific aspects that need to be considered to produce gears with internal or external teeth of the cylindrical type with vertical or inclined teeth. Generating the gears appeared as a necessity for the reconditioning of the components of the processing machines and of the electric machines made both in the process of elaboration of the bachelor’s and the laboratory works, with reduced energy resource consumption and low pollution as low as possible. After the construction, we past to identify the dimension that have implications for both mechanical and kinematic resistance to achieve a product with good cinematic and functional characteristics. After that are made an analysis of the layers generated, both from the computer simulation and from the point of view of the analysis of layers physically generated on a gear tooth with external teeth.

Specialty literature demonstrates the direct link between gastro-esophageal reflux diseases (GERD) and dental errosion (DE). Patients diagnosed with GERD often shown dental tissue loss in the enamel and dentine, somentimes going as far as opening the pulp chamber. Modern minimal invasive treatments make use of the current performance of cements and prosthetic materials (composites and ceramics) to conserve healthy enamel and dentine, in comparison to classic reconstruction methods.

The paper is treating the strength analysis of the main deck structure of an inland navigation catamaran for 30 passengers. The main deck should have high stiffness and high strength to resist to external loading and endure high stresses from combined bending and torsion loads. Different materials for sandwich structure of the deck have been analysed by using the Finite Element Method in order to determine the solution which accomplish better designing criteria regarding allowable stress and deformations and total weight.

Nowadays scientific researchers aim to develop new material designs for space structures that can withstand the harsh conditions in space environment. Another goal is to reduce the weight and the launching cost of the structures. A solution to those needs is to integrate fiber reinforced polymers in spacecraft structural components. Radiation shielding is a requirement that has to be met by the materials used to manufacture space structures. Protons are one of the many charged particles that can influence the integrity of materials in space. In the present study three material designs were developed and their ability to shield proton beam irradiation was evaluated. The material designs consist in advanced composite materials (carbon fiber reinforced polymers - CFRPs) that integrate the concept Low Z - High Z - Low Z (tantalum foil) and metallic coatings. Simulations were performed to determine the penetration depth of an ion beam (energy 15 MeV) in the proposed material designs. It was observed that the beam’s penetration depth through a CFRP sample with Ta foil (sample’s thickness 2.08 mm) was about 75% of the sample’s thickness, 58% for CFRP sample with Babbitt coating (sample’s thickness 2.28 mm), 56% for the CFRP sample with Zn coating (sample’s thickness 2.28 mm) and 55% for the CFRP sample with Zn/Monel coating (sample’s thickness 2.28 mm). It seems that the proposed material designs provide ion beam protection similar with an aluminum sample of 2 mm thickness. The experimental procedure confirmed the results obtained from the simulations, all the material designs providing protection in case of proton beam irradiation with an energy of 15.8 MeV.