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Two compounds containing mesogenic cores based on dithiophene and dithienothiophene or fluorene units and hexyl end groups have been synthesized and their thermotropic properties were studied. The mesomorphic behaviour has been analyzed in the thermal stability range, by three complementary methods: polarized light microscopy, differential scanning calorymetry and variable temperature wide angle X ray diffraction. It was established that both compounds form a mesophase at low temperature, whose architecture depends by the mesogen molecular structure. By thermal treatment of the compounds in the mesophase stability range continuous ordered films have been obtained. Keywords: liquid crystal, internal plasticizer, ordered film

Assuming that the “structural” elements of a multiphase fluid (hydrogel, drug or fluid particles) move on continuous and non-differentiable curves (fractal curves), a new theoretical model that describes the drug release processes from polymeric hydrogels is established. This model, namely fractal hydrodynamic model, is based on two equations: the momentum and probability density conservation laws. The fractal potential, from the momentum conservation law, is a measure of the non-differentiability of the movement curves and controls the drug release processes. The model allows us to evaluate some characteristics of the hydrogel network, such as a distribution parameter for drug particle inside hydrogel. The novelty of this approach is that the system complexity is replaced by fractality, eliminating thus the whole classical “arsenal” of quantities from the standard physics based on the assumption of continuity and differentiability of physical quantities (differentiable physics). Keywords: fractal hydrodynamic, drug release, polymer, hydrogel

The carpet waste fibers and waste glass that create a serious environmental problem can be converted into useful products. The use of these waste materials in a cement-based composite can be a promising direction for waste reduction and resources conservation. In this study, several tests carried out to investigate the performance of control mortar using recycled glass and fibers as a fraction of aggregates in a cement-based composite. These tests included compressive strength, flexural strength, flexural toughness and water absorption. The results revealed that carpet waste fiber and waste glass could be reused as substitutes for conventional materials in cement-based composites. Keywords: Cement-based composite, carpet waste, waste glass, polypropylene fibers

The objective of this study was to develop some new hybrid hosts based on dendrimers and montmorillonite designed for 5-Fluorouracil drug encapsulation. The presence of drug within the hosts was pointed out using different methods like FTIR Spectroscopy, X-Ray Photoelectron Spectroscopy (XPS), Thermogravimetric analysis (TGA), UV-Vis Spectroscopy and X-Ray Diffraction. The UV-Vis results showed that the dendrimer type involved in the hybrid hosts influenced the drug release. Keywords: antitumoral drug, dendrimer, montmorillonite, drug release system

The thermo-mechanical behavior of silica-reinforced crosslinked elastomers has been examined by conducting shear thermorheological experiments and microstructural evaluation on two series of randomly crosslinked poly(dimethyl-siloxane) (PDMS). For all the samples studied here it was found that due to the featureless mechanical spectrum, the time temperature superposition (TTS) principle could not be applied to expand the accessible frequency range by the construction of master curves. Characterization of the filler particles before and after their inclusion into the PDMS matrix was conducted by dynamic light scattering (DLS) and transmission electron microscopy (TEM). These observations are discussed with respect to recent evidence that particle clustering may occur in non-crosslinked systems. Finally, short time high temperature aging (up to 30 hrs) experiments were observed not to influence the viscoelastic behaviour. Keywords: highly crosslinked siloxane elastomers, linear viscoelasticity, time-temperature superposition, silica filler

The increasingly wider scale use of various foreign materials in Orthopaedics and Traumatology require long-term study of their interaction with adjacent bone, with soft tissue, and also the integration of these materials into the bone tissue. One of the likely consequences of using implants and metal fasteners is the production of conductance disturbances of bone which are dependent on the type of material used, with major implications for its biology and by default on fracture healing. The purpose of this paper is to highlight the changes in focal bone fracture biopotentials depending on the chemical composition of biomaterials used. The study is experimental, on a group of 23 Wistar rats which were created femur bone defects that were repaired by autotransplantation of the hip bone with different wire set. The potential difference between the graft and the graft bed was measured and was correlated with the chemical composition of biomaterial. The largest potential differences were reported with aluminium wire, copper, and nickelin wire, while V4A wire (alloy of nickel, chromium and titanium) determined the smallest disturbance of these biopotentials. Keywords: biopotentials, aluminium, copper, V4A, bone callus

The canning of fuel elements in nuclear reactors is subjected to stress and strains, which may cause failure if the material does not possess sufficient ductility. Of particular interest is localized strain in the circumferential or transverse ductility. The ring expansion test has been used for the determination of what has been called the transverse ductility of fuel element cladding. However, after some thought, it is realized that the ductility determined in this test does not really represent the determination in a fuel pin. In this paper some results, which serve to illustrate the limits of the test to rank materials, have been discussed.

CaCO3 is the main component of the raw materials powder mixture to obtain Portland cement. In the clinkerization process, with increasing the working temperature, physico-chemical processes take place in the raw materials, the most important being the endothermal process of CaCO3 decomposition. Thermal efficiency of the plant is given by decarbonization degree of raw materials at feeding rotary kiln. It is proposed a mathematical model for correlation decarbonization degree with the main parameters (temperature, time, granulometric characteristics of the raw materials).

Acrylic adhesives show high stability towards atmospheric agents and degradation resistance. On the other hand they have low adhesion for low energy surfaces (non-polar thermoplastics: polyethylene, polypropylene etc.). Pressure sensitive adhesives based on hybrid acrylic polymers could eliminate these drawbacks by combining the performances of classical acrylic adhesive with those of elastomeric adhesives. This work is focused on the study regarding the performances of pressure sensitive adhesives based on hybrid acrylic polymers. Peel strength, shear strength and tensile strength are also determined. Keywords: acrylic adhesives, pressure sensitive adhesives, acrylic saturated rubber, hybrid pressure sensitive adhesives