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Physical Properties of Crystalline Infrared Optical Materials
Published in Paul Klocek, Handbook of Infrared Optical Materials, 2017
James Steve Browder, Stanley S. Ballard, Paul Klocek
Notes: Magnesium oxide, also called periclase, is a cubic crystal of fairly high hardness and high melting point. Although less hard than sapphire, it may be pressed against metal gaskets to form a leaktight seal. This method, though not always successful, has been used for sealing magnesium oxide windows to absorption cells at high temperatures. The crystal can be cut on a disk grinder with no lubricant. Hard work with an aluminum oxide finishing cloth is necessary to get a smooth finish. It can also be used without polishing if a perfect cleav-age of the single crystal has been obtained. Some specimens show little O–H absorption, probably due to water. The polished surfaces of optical components of magnesium oxide can be protected from attack by atmospheric moisture with evaporated coatings of silicon monoxide. Magnesium oxide has a slippage plane that may affect the mechanical strength of certain optical components.
Development and Characterization on the Isothermal Kinetics of Mg(OH)2-sol Synthesized by Chemical Method
Published in Journal of Asian Ceramic Societies, 2022
Qingdong Hou, Jinlian Li, Luo Xudong, Zhipeng Xie, Di An
Due to the simple chemical properties and structure of Mg(OH)2, it is an important model system for researching the dehydrogenation mechanism of layered hydroxides at the atomic level. The process of preparing periclase by dehydroxylation of magnesium hydroxide is generally considered to be a two solid phase reaction process of Mg(OH)2 and MgO. The formation of MgO and its industrial applications mainly depend on the conditions of dihydroxylation. Therefore, the transformation of refractories with high density and low specific surface area to high chemical reaction active materials with low density and high specific surface area provides an important theoretical basis for industrial production [8].
MHD flow of MoS2 and MgO Water-based Nanofluid through Porous Medium over a Stretching Surface with Cattaneo-Christov heat flux model and convective boundary condition
Published in International Journal of Ambient Energy, 2020
Sannu Venkateswarlu, S.V.K. Varma, P. Durga Prasad
Molybdenum disulphide () is a semi-conducting material is made up of sulphur-molybdenum-sulphur triple-decker layers freely bound by van der Waals interactions. have a wide range of applications like, lubricating oils, greases (because of its excellent lubricate) and solid lubrication additive in composite materials. The comparison of bulk molybdenum disulphide and nano-sized molybdenum disulphide usually takes superior tribological properties and therefore bring progressively extensive consideration. Also, Magnesium oxide (MgO) or magnesia is a white hygroscopic solid mineral that happens generally as periclase and is a source of magnesium. MgO is a refractory material solid, which is chemically and physically stable at high temperatures. It has two advantageous characteristics: (a) high thermal conductivity and (b) low electrical conductivity. MgO is used in agricultural, environmental, chemical, construction and industries etc. Kasaeipoor et al. [10] deliberate the heat transfer characteristics of natural or free convention of a rigid body filled with MgO-water nanofluid by using Lattice Boltzmann method. Heat transfer characteristics and Ag-MgO water micropolar hybrid nanofluid over a permeable channel explained by Sheikhzadeh et al. [11]. They observed that increase in Reynolds number, the temperature of the nanofluid reduces in the area between the two walls; while the microrotation parameters near the hot wall decrease and near the porous wall increase. MgO-NBCNT hybrid nanofluid with thermal radiation and magnetohydrodynamic effects are examined by Ghalambaz et al. [12]. They are noticed that using the composite nanoparticles increases the convective heat transfer. However, the rise of the volume fraction of nanoparticles would reduce the overall enhancement. Considering a convective dominant regime of natural convection flow with Rayleigh number of 107, the maximum enhancement ratio (Nusselt number ratio compared to the pure fluid) for the case of glass ball is about 1.17 and for the case of aluminium metal foam is about 1.15 when the volume fraction of hybrid nanoparticles is minimum as 0.2 per cent.
Structure and thermal investigation of the effect of laser radiation in Chitosan-MgO nanocomposite film
Published in Radiation Effects and Defects in Solids, 2020
S. A. Nouh, B.O. Alsobhi, A. Abou Elfadl, K. Benthami, K. D. Khalil, S. M. Riyadh
Chitosan is an alternative to replace environmentally threatening materials due to its unique properties such as non-toxicity, good biocompatibility, biodegradability, and antimicrobial and anti-fungal properties (1,2). Chitosan is a deacetylated product of chitin, derived from crab and shrimp shells. It is a polysaccharide with a linear polymer of β-(1,4)-2-acetamido-2-deoxy-dglucopyranose units. Although chitosan films exhibit remarkable properties, poor mechanical, thermal and barrier properties restrict its usage in a wider range of potential applications (3). Hence, chitosan has been reinforced by preparing nanocomposites with various nano-fillers (4,5). Magnesium oxide (MgO), also known as magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase. It is used as a nanofiller to improve the properties of materials (6–8). MgO nanoparticles possess many interesting features including thermal and electrical insulation, good biocompatibility, and a large surface area-to volume ratio (9). Thus the nanometer sized MgO has been in great demand in recent years with a broad-range of applications (9). Nanomaterials have become an attractive field for researches due to their size dependent magnetic, electrical, optical and mechanical properties (10–12). The size dependent properties, together with the large surface to volume ratio in nanocomposites have made them more unique than the bulk form (13). The thermal stability, as well as the solubility, of the system is optimized by the use of polymeric matrix constructing a metal–polymers nanocomposite with additional novel catalytic, conductive, magnetic and optical properties (14). The merging of metal nanoparticles in the polymer matrix will improve its physical properties so that the obtained nanocomposite will be suitable for different applications (15,16). On the other hand, the laser irradiation of polymer films can cause changes in the thermal, optical and structural properties (16). The prompted physico-chemical property modifications in the polymer films have grabbed the attention for numerous applications (17). Several studies have been performed on the modification of the physical properties of polymers using nanoparticles (18–26). The present study deals with the investigation of the effect of laser radiation on the structure and thermal properties of chitosan-MgO nanocomposite aiming to study the possibility of enhancing its properties and refining its performance in different applications.