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Severe plastic deformation (SPD) is a manufacturing technique for producing bulk ultrafine grained materials and nanomaterials, the advanced grain refinement obtained by SPD substantially improving structural and physico-mechanical characteristics for the processed material. Equal-channel angular pressing (ECAP), the main SPD technology, entails pressing test samples through a die containing two channels equal in cross section and intersecting at a certain angle. The billet theoretically deforms by simple shear and retains the same cross sectional area to allow repeated pressings for several cycles. A commercial Al-Mg-Si alloy (6063- T1) was investigated in this study. As-received 6063-T1 alloy was firstly analyzed in OES and XRD tests. The specimens were subsequently processed at ambient temperature for a number of passes up to nine (one, three, six and nine ECAP passes), using a die channel angle of 100°. After ECAP, samples were cut from each specimen (ECAP treated and as-received) and prepared for microstructural investigations (SEM) and mechanical testing (compression and microhardness tests, fracture surfaces analysis). Furthermore, multiple correlations between ECAP processing parameters and the resulting microstructure and mechanical properties for the ECAP treated 6063-T1 alloy were also determined. Keywords: ultrafine-grained materials, aluminum alloys, severe plastic deformation, equal-channel angular pressing

Hormones are chemical substances which transmit a message as a signal within a physiological system between the place where they are secreted and the place of their receptors where they have the biological action. In the last decades the number of studies on phytohormones has increased continuously. In this study, polyurethane microstructures with and without brassinolide were synthesized in order to assess the release rate. Two different types of drug carriers were obtained (ether- and ester-based microstructures) and the evaluations were done by using two different methods: the measurement of microstructures’ size and the determination of free brassinolide concentration. The results suggest that ester-based polyurethane microstructures degrade faster and the two methods present very similar results. Keywords: brassinolide, drug carrier, DSC, polyurethane, UV-Vis, zetasizer

An increasing number of railway vehicles are using rubber springs as suspension elastic elements. Rubber is a suitable material for suspension purposes due to of its intrinsic properties and due to of the variety of forms into which it can be made. The clouth-type rubber spring may be used in both primary and secondary suspension of the vehicle and it may ensure the desired characteristics by setting the shape of its metallic components. In the present paper, a finite element static analysis was performed regarding the deformation of the clouth spring rubber under the action of various loads: vertical, longitudinal and transversal. The simulations allowed determining the distribution of deformations within the rubber element, the magnitude and the location of the largest deformation. Keywords: rubber, railway vehicle, suspension, clouth-type spring

Polyester coating of copper alloys is part of the technological procedures meant to improve the performances of metallic parts in order to reduce the rate of premature removal from operation. The paper highlights the positive influence that copper alloys coating with polyester impregnated with 5 - 10% graphite has on the main mechanical characteristics, especially the wear resistance. The effects on the wear, fragility and structural modifications have been determined on Amsler testing machine by means of roller-roller type couplings: polyester coated copper alloy – treated copper alloy; treated copper alloy - treated copper alloy. The comparison revealed the positive influence of the thin layer of polyester as lubricating agent, thermal barrier, electrical insulator, damping layer, and stress dissipation medium it also established the temperature limit up to which it is recommended to use the polyester coating in industrial applications. Keywords: polyester, graphite, cooper alloys

The paper presents comparative analysis for different solutions for the body of an internal spur gear used in a ground movement system of a drone with aerial and terrestrial movement capability. The comparative analysis is made from natural frequencies perspective and the purpose of the analysis is to reduce the weight of the drone without affecting its mechanical resistance and vibrational characteristics. Keywords: internal spur gear, modal analysis, natural frequencies, drone

This paper presents the influence of subsequent pressure of high-density polyethylene (HDPE), polymethyl methacrylate (PMMA), polycarbonate and acrylonitrile butadiene styrene blend (PC+ABS) on some mechanical properties when obtained through the injection of items from various industries. The HDPE samples were obtained at the following subsequent pressure: 800 bar, 900 bar, 1000 bar, 1100 bar, and 1200 bar. The PMMA samples were obtained at the following subsequent pressure: 450 bar, 550 bar, 650 bar, 750 bar, and 850 bar, and PC+ABS samples were obtained at the following subsequent pressure: 500 bar, 600 bar, 700 bar, 800 bar, and 900 bar. Determining the mechanical properties was made using determining methods of tensile properties, of Izod impact test, and Shore Durometer hardness test. It was observed in the case of the three analyzed polymers that increasing the subsequent pressure when injecting HDPE leads to a slight increase of hardness, and in the case of PMMA and PC+ABS blend, an increase in the subsequent pressure leads to a decrease in hardness. The Izod shock resistance for HDPE and PMMA decreases along with the increase of the subsequent pressure. In the case of PC+ABS, an increase of the subsequent pressure from 500 bar to 700 bar leads to a decrease in the shock resistance from 68.675 kJ/m² to 51.475 kJ/m². A further increase in the subsequent pressure to 900 bar leads to an increase in the shock resistance up to 63.900 kJ/m². The tensile strength at break is influenced by the subsequent pressure. An increase in the subsequent pressure in case of HDPE and PC+ABS blend leads to an increase in the resistance of the tensile strength at break, whereas in the case of PMMA, an increase in the subsequent pressure leads to a decrease in the resistance of the tensile strength at break. Keywords: high density polyethylene (HDPE), polymethyl methacrylate (PMMA), acrylonitrile butadiene styrene polycarbonate blend (PC+ABS), tensile tests, Izod impact test, Shore Durometer hardness test

In the medical field of plastics is and will be most useful. Their processing involves engineering concepts which assumes the most diverse risks. But there are conditions, depending on the identification between offer and demand of such services. They come as effects of the concrete availability of resources of all types, of caring facilities, comparing with the demand based on the need for health. In this context the analysis due to risk engineering is appropriate in the management accomplishments of the processors, respectively as it can be used at national and international levels, having effects on the efficiency of the usage of al the involved resources. Keywords: industrial system, risk engineering, plastic materials

The placenta handles the exchange of oxygen and nutrients from the mother to the fetus. Normal placentation and placental development are critical for a successful pregnancy. In this study, the placenta is obtained from normal pregnancy and of normal vaginal delivery. The polymeric cast of the fetal vasculature of the full-term placenta is used to perform a numerical simulation of the blood perfusion in the placenta. Vascular corrosion casting is an established method of anatomical preparation that has proven to be an an excellent tool for detailed three-dimensional (3D) morphological examination of normal and pathological microcirculation. Performed numerical simulation indicated that the velocity profiles in the placental vessels are close to parabolic profiles. Keywords: placenta, corrosion cast, numerical simulation, fetoplacental vasculature

In the European Union, the concept of sustainable development covers all the environmental fields, from development politics to the appropriate management of waste, in respect to the future generations. Therefore, the aim of this study is to prove that electronic waste scraps can be used to manufacture a new modern and ecological composite material, which can be used in construction field. The Electric and Electronic Equipment (EEE) amounts, on the market, are increasing from one year to another. At the end of life, only half of the generated waste, named e-waste or Waste of Electric and Electronic Equipment (WEEE), is collected. Knowing that the e-waste is framed as hazardous waste, because of its hazardous substances content, the challenge of our society is safe recycling, to confer security to human health and environment. The obtained composite is a new material which contains cathode ray tubes (CRT) glass waste and plastic scraps from WEEE. The composite experimental strength results (39.24 N/mm2), entitled its classification into the mortars category. The WEEE recycling method used to obtain this type of composite is an environmentally friendly one. Keywords: cathode ray tubes (CRT), composite, plastic, waste recovery