The purpose of this experimental study is to present the design and biomechanical characteristics of cemented total knee prostheses type rotating-hinge RT-PLUS® (Smith&Nephew), as well as to evaluate their use in severe haemophilic knee arthropathy with major bone damage, ligamentous lesions, axial deviations and muscle retractions. We retrospectively evaluated 5 patients with severe haemophilic arthropathy with an average age of 48.5years. The functional results are good, with a significant improvement of range of motion (ROM) and pain relief resulting in a much better life quality. We did not have any stem loosening or any other complications except 2 wound healing problems which were treated successfully. The authors recommend this type of arthroplasty in severe haemophilic knee arthropathy or in any primary knee osteoarthritis with severe bone loss or any kind of ligamentous lesions.
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Importance and use of composite materials are no longer a subject that should be emphasized. They offer a successful replacement for classical materials in most areas of engineering, conferring similar elastic-mechanical properties to metal or non-metal alloys with several advantages such as reduced mass, chemical resistance etc. Considering this, knowledge of the elastic-mechanical characteristics is of utmost importance. The present article aims to create a finite element model that can predict the longitudinal elastic modulus of a double-layered composite material based on the elastic characteristics of its constituents. For this, the elastic characteristics of the constituents were determined, then used in the finite element analysis thus obtaining the Young’s modulus for the numerical composite material. Also, the longitudinal elastic modulus of the resultant composite was determined experimentally. The results of the finite element model were compared with experimental values.
In this research are establish the technology of 3D printable parts by the principle of FDM 3D printed for threaded made by PLA, ABS, Nylon or PETG. In the paper are present first the dimensional generation and specific aspects that need to be considered to produce threaded with internal teeth of the metric, round or trapezoidal type. Generating the threaded appeared as a necessity for the reconditioning or made of the components of the processing 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, it is identify the dimension that have implications for both mechanical and kinematic resistance to make 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 for a threaded with internal teeth. At the end are presented which are necessary for operations to obtain a product with good features starting from two types of thread generated 8x2 and 10x2 moments.
Turmeric, with its active component curcumin has been regarded lately as an important potential therapeutic agent due to its properties and many uses. Further research needs to be done both on animals and humans in order for it to be used at a large scale. As curcumin gets absorbed better through topical and not oral administration, curcumin-based pharmaceuticals with skin passage must be devised. In order for this to be done, the need for a standardized, verified and simple extraction method and one for ointment preparation with stability in time rises. We propose in this study a method for curcumin extraction, one that ensures an adequate stability in time and a method for pharmaceutical control.
The crystal structure of tetrakis(2,2’-bithiophene-5-yl)silane, C16H10S4Si0.5, has been determined at 293K in the Monoclinic (I2) symmetry. The Si atom has quasi-perfect tetrahedral geometry and bithiophene unit are quasi-planar. Comparison of Si-C bond lengths with literature data indicates an electron donating effect of the terminal thienyl ring on the first C linked to the Si central atom. The study of C-C bond lengths reveals a much more aromatic character for the four thienyl rings directly linked to the Si atom. The molecular packing arrangement shows that each molecule presents eight intermolecular contacts.
The paper presents the obtaining of zinc and zinc composite coatings using electrochemical TiO2 nanoparticles as well as the determination of the influence of gelatin used as an additive on electrically co-deposited layers. The obtained coatings were studied at the electronic scanning microscope (SEM) for microstructure observation. A distinction was made between the pure zinc electro-deposed layer and the influence of nano-TiO2 on the morphology of zinc nanocomposite layers Zn/nano-TiO2, as well as the determination of the degree of inclusion of nano particles of TiO2 into the zinc matrix. It was confirmed that with the introduction of nano-TiO2, both the roughness of the electro-deposed layer and the micro hardness of the electro-deposed layer significantly increased compared to the micro hardness of the pure zinc electro-deposed layers confirming the existence and beneficial effects of nano-TiO2 in electro-co-deposed nano-composite layers.
The paper focuses on the obtaining of novel nanocomposite hydrogels based on polyacrylamide and layered double hydroxides (LDHs) modified with double bonds. The modification of LDH clay was investigated by FTIR, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analyses. Mechanical properties of the nanocomposite hydrogels were employed by compression and rheological measurements. The formation of exfoliated and intercalated structures was evidenced in transmission electron microscopy (TEM). Chemical cross-linking of hydrogels using both classical cross-linker and modified clay was an efficient method to improve the mechanical properties of novel nanocomposite hydrogels. These hydrogels with improved mechanical properties could be further tested for biomedical applications such as tissue engineering.
The thermal coefficient of linear expansion, the electrical conductivity and dielectric permittivity of fabric reinforced hybrid composites with filled stratified epoxy matrix were investigated. The measurements of electrical conductivity and dielectric permittivity had been performed, using standard method regarding electrical resistance and electrical capacity. In order to point out the effect of filler and of the spatial distribution of reinforcement layers, the medial layer of fabric was especially prepared by introducing copper wires in the woven. So, the medial layer is made of different types of tows (carbon, aramid, glass). This attempt is made in order to design a composite able to provide information about its state during various loading. The results showed that the fillers did not improve the electrical parameters of epoxy matrix, but they led to reduce the thermal coefficient of linear expansion. The thermal and electrical behavior of hybrid composites varied in dependence of number of carbon layers and fiber orientation.
In this paper, the potential of using ethylene-vinyl acetate (EVA) filled with multi-wall carbon nanotubes (MWCNT) composites for strain sensing was investigated. Stress relaxation experiments were conducted on injection-molded samples, and the stress and electrical resistance were measured in situ during the relaxation process. Based on the experimental results, it was found that the electrical resistance of the EVA/MWCNT composite increases with increasing strain, and exponentially decreases with relaxation time, indicating the capacitive behavior of MWCNTs. The maximum electrical conductivity of 7.35×10-4 S/cm was obtained for the EVA/MWCNT composite with 5 wt.% at 180°C, whereas higher piezo-resistive sensitivity was obtained for the composite with 3 wt.%. The electrical percolation threshold was found to increase from 0.223 wt.% at 140°C to 0.994 wt.% at 180°C.
In this paper we present a comparative study on tensile failure behavior of polymer stiffened composite shell structures, using infrared thermography and finite element analysis through the ABAQUS 6.13 program. The establishment of the distortion of some rectangular shaped specimens was followed. In these specimens a hole with a diameter of 15 mm was applied centrally. By means of infrared thermography, was studied experimentally the variation of the deformations over time, depending on the stress force and the evolution of the thermal field in the crack area. Simulation models of failure behavior have been performed, which have been validated by experimental results.