Advanced Materials Research Vols. 488-489

Abstract: CaO samples prepared from calcining the powdered waste shells at 1300°C for 4 h were tested the efficiency of humidity adsorption. The samples were characterized via X-ray diffraction (XRD) and Fourier transform infrared analysis (FT–IR) to identify the characteristic of CaO after humidity adsorption test. The results indicate that duck eggshells are highest capable of humidity adsorption while hydration rate of chicken eggshells is rather equal to that of cockle shells, and lowest hydration rate was found with sample prepared from Mussel shells. Therefore, we can conclude that the waste shells are suitable to be use as humidity adsorbent for commercial in the future

Abstract: Butylparaben is widely used as a bactericide and as an antimicrobial agent in the formation of personal care products (PCPs). Owing to a certain estrogenic activity, a possible relationship with breast cancer has been proved by many researchers. The removal efficiency of butylparaben in aqueous solutions was studied using advanced oxidation processes (AOPs). These results indicate that the reaction rates for the ozonation of butylparaben in water are higher under the concentration of ozone 5 mg/L in alkaline condition. The original concentration of butylparaben almost degraded within 50, 30, and 20 min at ozone concentrations of 1, 3, and 5 mg/L, respectively at pH 11 runs. The ozonation imposed butylparaben with a time dependence that appeared to follow pseudo first-order kinetics. The original butylparaben was degraded 50 %, 40%, 35%, and 32% within 24 hr at pH 3, 6, 9, and 11 respectively by UV/TiO₂ process in the O2-sparged concentration of 30 mg/L. The rate constants are 0.045, 0.043, 0.025, and 0.020 hr-1 at the butylparaben concentrations of 10.30, 20.60, 30.90, and 41.20 μM, respectively.

Abstract: Aging of Fe-Cu alloys or steels containing copper may result in the formation of the dispersion of nanometric precipitates in the matrix and, thus, causes a great increase in the strength of the alloys. A model is developed describing the aging process of Fe-Cu alloys. The model is first satisfactorily verified by comparing with the reported experimental results, and then applied to calculate the microstructure evolution during aging a Cu-Fe alloy. The numerical results demonstrate that the nucleation of the precipitates occurs after a period of incubation. Since that time on the microstructure evolution is the result of the concurrent action of nucleation, growth/shrinkage and structural transformation of the precipitates. In the late stage of aging almost all the precipitates are of 9R structure. The mean particle radius varies linearly with the cube root of time

Abstract: Ceria-based materials are widely used in industrial applications such as catalyst supports, catalysts and electrolytes. Various applications require different morphological particles. Spray pyrolysis (SP) is a well-known process for ceria particle fabrication because SP has the advantages of simple and continuous process. Although various studies have discussed the particle morphology formation of SP, some questions are still unclear. In order to solve these questions, this study investigates the morphology of ceria particles from various precursors using SP. By combining the experimental data of scanning electron microscopy, transmission electron microscopy and focused ion beam, the result suggests that the particle formation mechanism is highly correlated with factors of hydrophilic-hydrophobic properties of precursors. Therefore, the morphology mechanism of SP for the ceria particles is proposed .

Abstract: Iran is recognized as one of the largest fossil fuels reserves resources in the world, but it is also suffer from mismanaged consumption. The consequences of this mismanagement have been considered in Iran during recent years and authorities have raised concerns about it. Identification of the optimized orientation and tilt angle for roofs in Tehran- The capital of Iran- in order to achieve the maximum daytime heat gain by photovoltaic cells and minimum energy loss at night in winter is the main purpose of this paper. So this paper makes a comparison in three shape of high-rise building in Tehran and their orientation. The results show that the appropriate direction for gaining more energy in Tehran are north-south and WE-NE direction and the cubic type of building in field of energy consumption is more economically for users

Abstract: Natural fiber composite is nowadays used as an alternative to conventional materials. In this work, the natural fibre, Reshira is tried with epoxy resin, for the first time, as a composite material to be used for various applications. The reshira fiber is chemically treated with sodium hydroxide for better adhesion between fibre and resin. The reshira fiber–epoxy composite is fabricated with varying chemical concentrations of sodium hydroxide solution, fiber lengths and fiber volume fractions. The composite samples are subjected to tensile, flexural and impact tests and the optimum composition that produces maximum mechanical performance is selected. Further the optimum sample is tested for its fracture toughness property.

Abstract: This paper presents the preliminary study of the Unground Palm Oil Fuel Ash (UPOFA) addition on the Compressed Earth Brick (CEB) characteristic. POFA as a by product of palm oil kiln was found out to have pozzolanic properties and could be used to create cementitious materials. Previous researches believed that original or unground POFA is not suitable as cement replacement due to its large particle size and porous structure. Compressed earth bricks of 100 x 50 x 25 mm with manual compaction with compression rate 2000 psi were produced with additional of UPOFA passing 300 µm sieve and it was discovered that the addition of 40% UPOFA could enhanced the bricks compressive strength up to 13.89 MPa and decrease the brick water absorption until 15.3%. Incorporating UPOFA in CEB production will definitely resulted in cost efficient considering cost saving in grinding process.

Abstract: Structural materials, such as steatite-based ceramic is considered one of the most useful engineering ceramic in place of alumina as a cost-effective way to meet performance requirements. The objective of the research here is to develop a dense body which exhibits good properties as mentioned by the two stage sintering method. Steatite powders used in this work were undoped steatite, steatite doped 20wt% ZnO and steatite doped 20wt% MnO₂. The green samples were cold-isostatically pressed and pressureless sintered at temperatures ranging from 950°C to 1200°C at heating rate of 10°C/min through two stage sintering before cooling down to room temperature. The results revealed an improvement in the densification of all the steatites through two stage sintering compared to the conventional sintering. At 1200°C, the steatite bodies with 20 wt% ZnO compositions achieved maximum bulk density of 2.79 g/cm3 which is 10.3% higher than the same steatite doped bodies which exhibited best result when it was conventionally sintered. As a result of bulk density improvement, two stage sintering exhibited outstanding effects in enhancing Young’s modulus and hardness of the steatite body.

Abstract: Transparent thin films of 3% Sr – doped TiO₂ were prepared by spin coating technique on a glass substrate and annealed at different temperatures. The optical properties of the films were studied using UV – Visible spectroscopy and Photoluminescence ( PL ) spectroscopy. The optical band gap is found to change with the annealing temperature of the deposited films. The PL emission spectra showed a sharp intense peak near the violet region. AFM analysis was used to study the surface topography of the films. The study shows potential applications of the prepared films in optoelectronic devices.

Abstract: Molybdenum catalysts supported on γ-Al₂O₃ and γ-Al₂O₃-MgO mixed oxide with varying loading of MgO (5, 10, 15, 20 wt% with respect to γ-Al₂O₃) were prepared successfully by wet impregnation method. The physiochemical properties of these synthesized Mo catalysts were studied by various analytical techniques such as N₂ adsorption–desorption (BET), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Temperature-programmed reduction (TPR).The results showed that the addition of MgO into the support affected the binding energies of the elements and reducibility of the metal oxides formed after calcination of catalyst samples due to change in metal-support interaction. Further, the characterization techniques showed that the active metal was well dispersed on the surface of support material.