Magnesium Oxychloride as known Sorel cement, has superior strength over the other cements, AND is used as bonding agent in various commercial applications. The amount of the magnesium chloride varied from 0.5 to 1.9 moles AND the cold crushing strength (CCS) of samples was measured. X-Ray diffraction (XRD) of matrix are investigated. The morphology AND Microstructure of the PHASES are characterized using a scanning electron microscope (SEM). It is believed that a molar ratio of MgO/H2O of 13/12 AND 1.5 moles of MgCl2.6H2O can produce a promising matrix composition for proper design.

In the present paper, the constructal theory is employed to determine the optimal configuration of three rows of NEEDLE-SHAPED fins. The heat transfer across the fins is due to laminar forced convection. Second order upwind scheme is used for discretization of the diffusion terms of governing equations. The pressure– velocity coupling is performed using the SIMPLE algorithm. The heat transfer is optimized subject to constant fin volume. The effect of Reynolds number AND thermal conductivity on the optimal configuration is investigated. The results obtained from the present simulations are in good agreement with the numerical results. The results show that pin– fins flow structure leads to the best performance when the pin– fin diameters AND heights are non-uniform. At Re = 100 AND 200, the optimal value of 𝐻 3/𝐻 1is 1. 3. It is revealed that at Re = 50, the optimal value for 𝐷 3/𝐷 1 is approximately 1. 1. The results demonstrate that heat transfer rate is an increasing function of the Reynolds number.

Zinc oxide nanopowders were synthesized by the simple sol–gel method from an ethanol solution of zinc nitrate hexahydrate. Structural AND surface morphological investigations were carried out using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR) AND ultraviolet–visible (UV–Vis) spectrophotometry analyses. XRD pattern showed that the zinc oxide nanoparticles exhibited hexagonal wurtzite structure. A multiple-layered structure of obelisk-SHAPED ZnO nanoparticles was achieved after calcinations. The average particle size of ZnO was around 20 nm as estimated by direct HRTEM observation. The size of sphere-like SHAPED ZnO nanoparticles was measured in the range of 20–80 nm AND the size of pyramid-like SHAPED annealed samples was achieved in the range of 40–100 nm with less agglomeration. The energy dispersive spectroscopy spectrum showed peaks of zinc AND oxygen. The sharp peaks in FTIR spectrum determined the Zn-O stretching AND absorbance peak of UV–Vis spectrum showed the wide bANDgap energy of 3.35 eV.

Background AND Aim: Color match between prosthetic restorations AND natural teeth is challenging in dentistry. The aim of the current study was to assess the effect of accelerated aging on color stability of two silica-based ceramics with leucite AND lithium disilicate CRYSTALLINE PHASES after glazing AND polishing surface treatments. Materials AND Methods: In this experimental study, 30 disc-SHAPED specimens (1. 5x10mm) of IPS e. max Press AND Ceramco III ceramics were fabricated according to the manufacturers’ instructions. The specimens were rANDomly divided into two groups of surface treatments (glazing AND polishing) AND were then subjected to accelerated aging for 300 hours. Color parameters were measured before AND after aging using a spectrophotometer. The L*, a* AND b* parameters AND the color change (Δ E) of ceramics (based on the CIE L*a*b* system) before AND after glazing were determined by spectrophotometry. Data were analyzed using two-way ANOVA AND t-test. P<0. 05 was considered statistically significant. Results: After 300 hours of aging, the color stability (Δ E), Δ L AND Δ b of polished group was less than that of glazed group. The two ceramic types were not significantly different in terms of Δ E (range: 1. 31 to 2. 53; P=0. 055). Conclusion: Glazed silica-based ceramics had higher color stability than polished ceramics after aging in our study. Color stability of silica-based ceramic systems was influenced by the surface texture AND not the type of CRYSTALLINE phase.

Eldar pine introduction to Iran dates back to many centuries ago. It has been severely changed in morphology in Khaf region AND two different forms emerged. This study aims at using anatomical traits to differentiate Conical AND Ball-SHAPED pines which are two new mutant forms of Eldar pine. The results of anatomical comparison showed that Conical-SHAPED pine is distinguished from two other pines in some valuable taxonomical traits, such as cross sectional form of NEEDLE, number of stomata on ventral face per unit area, number AND position of resin ducts. Also the difference in characteristics like cuticle thickness, stomatal interval space in row, number of stomata per NEEDLE unit area, NEEDLE perimeter AND length imply increasing the adaptation potential to aridity in Conical-SHAPED pine spec. nova in comparison with Eldar AND Ball-SHAPED pines.

Mechanical alloying of an elemental powder mixture with stoichiometric composition of Ti0.4Ni0.5Nb0.1 was conducted using planetary ball milling. The assessment of the formed PHASES was investigated using semi-empirical Miedema Model. In addition, the milled product was characterized using various techniques; X-ray diffraction studies revealed the formation of Ni (Ti) solid solution after the first hour of milling. However, dissolution of Nb was not found in neither of the other elements. After 7.5 h of milling, the formation of NiTi-based intermetallic compound begins while Nbis still remained as a free element. Finally, after 10h of milling, an amorphous phase was formed which remained for the next 10h. Field emission scanning electron microscopy investigations showed that a homogeneous structure is formed after 20h of milling, but further milling increases the product size due to agglomeration AND cold welding of the relatively finer milling products. Transmission electron microscopy confirmed the presence of both the nano-CRYSTALLINE NiTi intermetallic compound AND amorphous phase. The experimental results were found to be in agreement with those of the thermodynamic calculations based on Miedema Model using Ni-Ti, Ni-Nb, Nb-Ti binary systems AND Ni-Ti-Nb ternary system that predicted the formation of Ni (Ti) solid solution AND immiscibility of Nb in Ti AND Ni. In addition, a slight difference in the value of Gibss free energy of formation was found between the intermetallic compound AND amorphous phase that confirms their presence in the final milled product. NiTiNb, nano-structured materials, mechanical alloying, thermodynamic calculations based on Miedema Model.