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Due to mechanical resistance characteristics, chemical corrosion and abrasive erosion resistance, the polymers are more widely used in equipments and installations that are exploited in different fluid hydrodynamic conditions. Among these applications there is the protection of surfaces of hydromechanic organs stressed by cavitation, like in hydraulic machines rotors and valves. Consequently, the research aimes the extension of using these and protection of other components surfacess hardly streesed by cavitation. The research in this paper points toward the behavior of modified polymer layer, coated on surfaces of bronze used in casting the propellers of maritim and river ships. The tests were performed in standard piezoceramic crystal vibrating equipment within Cavitation Laboratory of Politehnica University of Timisoara. The damaging intensity of equipment is much greater than any cavitational vortex, created by ship propeller, hydraulic turbine or centrifugal pump. The obtained results, compared to both recorded on uncovered surfaces with polymer layer and recorded on surfaces covered with HVOF composite materials layers, show an increased resistance that implies the increased exploiting duration of those surfaces.

In the present paper, the authors dealt with the synthesis and characterization of a new type of dynamic membrane with polysulfone matrix and ionic polymer electrolyte: polysulfone-sulfonated polyetherether-sulfone (PSf-SPEEK). The PSf-SPEEK composite membranes were formed by ultrafiltration of SPEEK gel on the polysulfone matrix in a CELFA System installation. The thickness of the PSf porous layer for the different membranes can be between 50 and 120 mm. The variation of SPEEK active layer’s thickness is dependent both on the concentration of the SPEEK solution in the feed, and on the velocity of the surface flow. The sulfonated polymer (SPEEK) superficial layer ranges from 35 to 75 nm, being thicker at low flow rates having a slight increasing related to the increase of the SPEEK concentration. Increasing the polymer concentration, from 0.5 to 2.5%, used in the feed solution leads to a doubling of the conductivity and a tripling of the ion exchange capacity. The maximum conductivity of the PSf-SPEEK dynamic composite membranes is 0.234 S/cm and the ion exchange capacity is 1.682 meq/g.

The paper describes the advantages of material deposition using the resistive vaporization method, so that new very thin layer, which is about ìm, could be used on polymer base structure. Due to the new properties involving the friction coefficient on plane surface, where some dynamic forces are acting, we may better control the performances. By analyzing the theoretical aspects of entropy rate production, we may determine the maximum friction providing the stability of wear avoiding the material deterioration during the process.

The increasing proportion of laparoscopic interventions in the surgical centers has, also, determined an increased incidence of specific complications, such as trocar hernia. Nowadays, there is no unanimously agreed concensus regarding the optimal closure technique of the trocar incision, wether it should include the suture of the aponeurosis or not at the 10 mm ports. There is, also, no consensus regarding the proper surgical technique for the trocar hernia repair- alloplastic or tissue repair technique.The purpose of the study is to present our experience on the alloplastic repair of the trocar hernias. It is a retrospective study that analyzes the results obtained by our clinicalteam regarding the alloplastic repair of the trocar hernias, over a five-year period, between January 2011 and December 2015. The recurrence and the occurrence rates of different complications (seroma, neuroma with postoperative pain, parietal infiltration, infections and mesh rejection), depending on the type of mesh used for the surgical repair,are studied.

Natural mixtures based on bioflavonoids, terpenoids, glycosidic compounds, polyphenols, anthocyanins and essential fatty acids are often more effective and non-toxic than many synthetic drugs. Betulin, a terpene compound with many key-roles in alternative medicine, is almost insoluble in water due to its pentacyclic structure. Different drug carriers are developed to improve the drug efficacy and release. This paper described the evolution of some skin parameters (transepidermal water loss, erythema and stratum corneum hydration) after a short and respectively a long exposure to a polyurethane carrier with and without betulin using sodium lauryl sulfate as reference. It was found that these compounds are safe for human use and the hydratant effect of betulin was reconfirmed.

Postoperative eventration is a quite common condition in patients with clinical records of abdominal surgery. The purpose of this study was to investigate the efficacy of use of 2 different types of meshes (Polypropylene mesh and ProGripTM mesh-self-gripping mesh) in the surgical treatment of incisional hernias. In this respect, we conducted a study in which we introduced 128 patients operated for incisional hernias. Patients were divided into 2 lots: group A (102 patients with polypropylene mesh) and group B (26 patients with ProGripTM mesh). From the analysis of the data studied, we noticed that the average duration of surgery and hospitalization for patients with ProGripTM mesh is lower compared to patients with polypropylene mesh. Also, the rate of local postoperative complications was lower when using the ProGripTM mesh (15.38%) than in the case of polypropylene mesh. In conclusion, we can state that the use of the ProGripTM heterologous mesh is beneficial in the surgical treatment of patients with incisional hernias. The major advantage of using this type of mesh is given by a shorter hospitalization period for these patients, as well as by a lower rate of local postoperative complications in these patients.

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.