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The increased demand for energy sources is the driving force to convert organic compounds into alternative fuels. Plastic waste disposal affects the environment, since they are not easily recycled and, during the recycling process, they can produce waste ash, heavy metals, or potentially harmful gas emissions. In the plant design for plastic converting into fuel, the chemical reactor is one of the advanced equipment in the field of chemical and process engineering. This study emphasizes the feasibility of pyrolysis process for valorisation plastics by producing energy-efficient products. In this respect, samples of polypropylene, polyethylene and polystyrene were used as models and subjected to pyrolysis processes at 450 °C, in the presence of two types of mesoporous silica materials, MCM-41 and SBA-15, using a modern developed reactor. The use of mesoporous materials increased the calorific value of the obtained oil and gas, thus improving the economic potential of the process end products. This study dealt with the extraction of oil from plastics termed as plastic pyrolysis oil (PPO) and plastics pyrolysis gas (PPG), with a composition rich in different types of hydrocarbons and they can be marketed at much cheaper rates compared to that present in the market.

For more than half a century, the use of plastic in agriculture has given farmers opportunities for growing fruits and vegetables regardless of the season, and at the same time achieving better quality compared to open-field cultivation. The use of plastics, through various specific techniques, helps reduce the consumption of various resources such as water, energy, fertilizers or pesticides.We could say that without these plastics a significant amount of cultivated fruits and vegetables could not be harvested in early conditions and could not be preserved and conditioned in controlled parameters.Plastic is a very important material for economy but also in everyday life. The use of plastic in agriculture has increased from year to year, thus contributing to both the increase of agricultural production and the improvement of the quality of food.Plastics are a wide range of synthetic or semi-synthetic materials that are used for various purposes. In the plastic industry, are used raw materials, such as cellulose, coal, natural gas, salt and, of course, crude oil. Plastics are extremely versatile materials and are ideal for a wide range of applications for industry as well as for consumers.

Single walled carbon nanotubes (SWCNT) and multi walled carbon nanotubes (MWCNT)/ vinyl ester nanocomposites with three different contents of carbon nanotubes (CNTs) have been prepared by the simple melt-compounding method. A fine and homogeneous dispersion of CNTs throughout vinyl ester resin has been noticed by SEM images. Two mechanical tests (compression and three point bending test) show that, compared to neat vinyl ester resin, compression modulus and compression strength of the nanocomposites have been significantly improved by about 9% and 14%, respectively, when incorporating only 0.15 wt.% MWCNTs. Furthermore, thermal behavior of SWCNT and MWCNT/ vinyl ester nanocomposites has been investigated and discussed based on differential scanning calorimetry (DSC) and thermo- mechanical analysis (TMA). Glass transition temperature (Tg) and coefficient of thermal expansion (CTE) have been increased and decreased, respectively, with increasing of CNTs content.

The bulk metallic glasses composites are a new class of bulk metallic glasses (BMGs), containing an amorphous metal matrix and reinforcing materials of metallic or ceramic nature in order to obtaining the desired combination of mechanical properties including strength, hardness, ductility and toughness. Composite materials of cylindrical form with the diameter of 10 mm and 5 mm in height were successfully prepared by hot-pressing of Zr – based glassy alloy powder and Fe – based nanocrystalline alloy powder in different volume fraction. The samples obtained were structural investigated by scanning electron microscopy and X-Ray diffraction and mechanically characterized by hardness and compression tests. It was found that increasing the volume ratio of the Fe-based nanocrystalline alloy up to a certain value leads to an increase in hardness and mechanical compressive strength.

Flame straightening is a technology process used to eliminate deformations. This method relies on local heating of the material to correct geometry or damaged parts. In the local automobile services its main use is for repairs of less critical deformed components. The maximum temperature and thermal gradient, heating time, cooling rate and number of heating cycles affect the mechanical properties since local heating can alter material microstructure. The aim of this research was to determine the mechanical characteristics of thin steel plates repaired by local heating associated with plastic deformation (similar to hot working) and cold straightening (similar to local cold working) for automotive side and door panels made of structural steel. Thin sheet plates, 0.9mm thickness, were deformed by impact and repaired by local heating using the flame and induction heating then plastically deformed while hot as well as straightened without heating. The heat repaired samples were studied by light microscopy to determine microstructure change and samples were tensile tested to determine their mechanical characteristics. Local excessive grain growth generates anisotropy, the assembly behaves as a composite material with regions that show significant plastic deformations while others little or no deformations at al. Without procedures adjusted to each material repairs involving heating are to be avoided, cold working should be employed when replacement is not possible.

This study comprises the studies performed on six in vivo failed centromedullary fixation devices, three made of stainless steel 316L and three of titanium alloy Ti-6Al-4V. Fractographic studies were performed using stereomicroscopy and scanning electron microscopy while metallographic studies were performed by light microscopy. Loading mode which caused failure was inferred based upon surface fracture topography and light microscopy studies were performed to observe if abnormal microstructures or inclusions could be the cause of the failure. In all cases the chemical composition was according to standard specifications and the microstructures appeared normal with low inclusionary content. The mode of failure was found to be fatigue and the crack initiation site was on the implant surface on roughness features and surface induced defects.

The aim of this study is to investigate the effect of alloplatic graft and platelet rich fibrin (PRF) , alone or in combination, on bone regeneration in Wistar rats femural defects. Bone defects were prepared in adults male of 20 Wistar rats. In a group of ten, the defect was filled with synthetic ceramic graft as an alloplastic graft; the others 10 were grafted with this alloplastic graft mixed with PRF. All animals were sacrificed on the 90th postoperative day and the femural bones were removed, histologic sections were prepared and the experimental sites were examined microscopically. Histologic examination revealed more new bone formation in the defects filled with alloplastic graft mixed with PRF than in the defects grafted with alloplastic graft alone. The platelet rich fibrin combination effectively induces new bone formation.

Most of the fixation implants for tibia fracture are made of various metallic alloys based on titanium or even stainless steel. But modern technologies and advanced materials offer endless opportunities of using polymers combined with various fillers to enhance and adjust mechanical properties in order to be as suitable and convenient for any patient.

Polylactic acid (PLA) is one of the most extensively used biodegradable aliphatic polyester produced from renewable resources, such as corn starch. Due to its qualities, PLA is a leading biomaterial for numerous applications in medicine as well as in industry, replacing conventional petrochemical - based polymers. The purpose of this paper is to highlight the mechanical properties, such as tensile stress, of pure PLA specimens in comparison with PLA based-composites, with three different added materials in PLA mass: Copper, Aluminum and Graphene, as well as the influence of filament angle deposition on these properties. In order to check if the the filling density of the specimen influences the ultimate tensile stress (UTS), three different filling percentages (60%, 80% and 100%) have been chosen in the experimental tests. In this context, the mechanical characteristics of four different filament types based on PLA material, starting from pure PLA to PLA with Aluminum, Copper or Graphene filler are compared. Understanding and controlling these parameters is essential for the successful use of PLA and PLA-based composites in different areas such as medical applications, sport equipments and light industry.These tests have been performed due to the fact there is a lack of information concerning the mechanical properties. In the scientific literature, such information is only available for expensive printing systems; for open source printers (as those used in these tests), the information is poor and for some new materials, even inexistant. According to the technical specifications, for an expensive printer the cost may exceed 3000 Euros, with a minimum layer resolution of 100 m, this type of printer can reliably reproduce many 3D objects accurately, in quiter conditions.

This work are made for determine the possibility of generating the specific parts of a threaded assembly. If aspects of CAD generating specific elements was analysed over time in several works, the technological aspects of making components by printing processes 3D through optical polymerization process is less studied. Generating the threaded appeared as a necessity for the reconditioning technology or made components of the processing machines. To determine the technological aspects of 3D printing are arranged to achieve specific factors of the technological process, but also from the specific elements of a trapezoidal thread or spiral for translate granular material in supply process are determined experimentally. In the first part analyses the constructive generation process of a spiral element. In the second part are identified the specific aspects that can generation influence on the process of realization by 3D DLP printing of the two studied elements. The third part is affected to printing and determining the dimensions of the analysed components. We will determine the specific value that can influence the process of making them in rapport with printing process. The last part is affected by the conclusions. It can be noticed that both the orientation and the precision of generating solid models have a great influence on the made parts.