Advanced Materials Research Vol. 787

Abstract: The preservation of religious art work sees the coexistence of opposing needs: first of all the fruition of the works themselves. This is ensured by promoting accessibility to a wider audience and setting up environments improving both the visibility of artifacts and well-being of guests. The second is the obvious need to protect objects exposed to the degradation caused by environmental factors. This can be reachead by creating suitable conditions for their own preservation. The works of art are made up of antique and composite materials ; their proper preservation advices vary from case to case according to the kind of materials they are made of. In many cases the ideal environmental conditions for the objects are not compatible with the most appropriate ones for the audience. Usually the compromise solution is not so simple also because the is often object to physical contact by the faithful , subjected to frequent expositions and microclimate changes related to temperature and humidity excursions and connected to the presence of total suspended particulate (TSP) mainly from intensive uncombusted residue smoking from incense and votive candles.

Abstract: Clay modified with organic surfactant, Cloisite 10A, 15A, 20A, 25A, and 30B act as effective adsorbent in organic wastewater applications. The experiment was tested using wastewaters from removal of skim NR from concentrated NR industry. The ability to remove organic contaminants from aqueous solution, based on different molecular structures of organically modified clays, was evaluated using UV/VIS spectroscopy, chemical oxygen demand (COD), biological oxygen demand (BOD), suspended solid (SS), total dissolved solid (TDS), total solid (TS) and total kjeldahl nitrogen (TKN). In addition the mechanical properties of nanocomposites product obtained from coagulating method were determined by tensile testing. It reveals that mechanical properties of nanocomposites were improved when compared to the original skim rubber. The thermal stability and the composition of the coagulated skim rubber-organoclay nanocomposites were determined by thermogravimetric analysis.

Abstract: Clay modified with organic surfactant, DDA-MMT, Closite 15A, 20A, and 25A, act as effective adsorbent in organic wastewater applications. Due to the inorganic character of MMT, the organic adsorption ability of MMT was improved by replacing the exchangeable cation. The experiment was tested using wastewaters from removal of skim NR from concentrated NR industry. The ability to remove organic contaminants from aqueous solution, based on different molecular structures of organically modified clays, was evaluated using UV/VIS spectroscopy, chemical oxygen demand (COD), and biological oxygen demand (BOD). In addition, other quality indicators of wastewater and product were measured before and after the treatment with coagulating method.

Abstract: The purpose of this study is to investigate the effect of moisture and temperature on the compressive strength of T300/QY8911 composites that tend to be used as structural parts of aircrafts. In aeronautical applications, the composites are exposed to severe environmental conditions, and it is known that hot and humid environments can degrade some aspects of the material performance especially the compressive strength. In this paper, an experimental study was carried out to determine the damage progressions. Scanning electron microscope (SEM) was also employed for fractographic investigations. It is observed that the failure of specimens tested in hot and wet conditions always occurs as a result of out-of-plane microbuckling that is attributed to the reduction of matrix strength. Fiber microbuckling model, fiber kinking model and combined model were employed for the compressive strength prediction of the unidirectional T300/QY8911 composites subjected to different environment conditions. Results show that the combined model is more suitable for the compressive strength prediction of T300/QY8911 composite systems when suffering severe environment conditions.

Abstract: This paper covers the results of an experimental investigation on mechanical and durability properties of concrete containing waste polystyrene based lightweight aggregate called Stabilised Polystyrene (SPS) as a partial replacement of natural aggregates. The properties investigated in this paper were water absorption by capillary action and total absorption, compressive strength and ultrasonic pulse velocity (UPV). The composite aggregate was formed with 80% waste polystyrene which was shredded to different sizes, 10% of a natural additive to improve the resistance to segregation and 10% Portland cement. The natural fine aggregate were replaced with 0%, 30%, 60% and 100% (by volume) of SPS. There was an increasing in water absorption and a decreasing in compressive strength and UPV with the increase in SPS aggregate content in concrete.

Abstract: Ultrasound can promote the dye-uptake in the dyeing process. The effects of ultrasound on the fiber, dye and dyeing system were investigated by dyeing cotton fabrics with a direct dye. The dye exhaustion exceeded 80% in 30 minutes with the assistant of ultrasound. Langmuir adsorption model could descript the ultrasound dyeing process of direct dye. The area of fiber accessibility of cotton fiber increased 1.68 times under the action of ultrasound. The absorbance of direct dye solution increased remarkably in the first 10 minutes of ultrasound irradiation. Ultrasound accelerated the diffusion of dye on cotton fiber, and then the diffusion coefficient increased 46 times

Abstract: Unintentionally doped GaSb films grown by Molecular Beam Epitaxy (MBE) on GaAs (001) substrates were annealed under different temperatures and time. It was found that the rapid thermal annealing (RTA) process can improve the optical properties. By changing annealing temperature and time, the optimized annealing temperature and times are found to be 650°C and 30s, respectively. Point defects and dislocations are two major kinds of defect in undoped GaSb thin films grown by MBE on GaAs (001) substrates.

Abstract: The electrical conductivity of network polytetraphenylcalix [resorcinarene (I) and sulfonated polytetraphenylcalix [resorcinarene (II) in the form of Н⁺, Na⁺ , Li⁺, Ag⁺, Ba²⁺, Ni²⁺, Cu²⁺, and Zn²⁺ cations was measured. It was found that the specific conductivity of the polymers in the form of doubly-charged metal cations was 0.2-0.4 S/m. It increased to 1-1.5 S/m when the polymer was in the form of singly-charged metal cations. The specific conductivity of the H-form polymer II became as high as 20 S/m. The self-diffusion coefficients and activation energies of metal cation diffusion in the polymer phase were calculated over the temperature range 298333 K.

Abstract: Doped BaTiO₃ powders were sintered by slip casting. Sintering was performed at the temperature of 1300oC, for 180 min holding time, in a conventional furnace. Additives were varied to study their effect on the densification and both dielectric and mechanical properties. The relative density of the obtained material was high, up to 96.5 0.6 % the theoretical density for the BaTiO₃-Al₂O₃ composition. For these samples, their mechanical and dielectric properties have been studied.

Abstract: In this work we describe the studies of preparation and stability of liposomes formed by 1,1'-[(3,5-didodeciloxycarbonyl-4-phenyl-1,4-dihydropyridine-2,6-diil) dimethylebispyridinium dibromide, novel lipid-like compound. The influence of the amount of amphiphilic compound, solvent and sonication time was studied. Liposomes were prepared by dispersing of compound in the corresponding media at a selected concentration by sonication using a probe type sonicator and characterised by atomic force microscopy (AFM) and dynamic light scattering (DLS) methods.