objective(s): this paper describes coating of magnetite nanoparticles (mnps) with amorphous silica shells.   materials and methods: first, magnetite (fe3o4) nps were synthesized by co-precipitation method and then treated with stabilizer molecule of trisodium citrate to enhance their dispersibility. afterwards, coating with silica was carried out via a sol-gel approach in which the electrostati...

background and purpose: recently, release of pollutants such as pharmaceuticals to the environment becomes one of the most important problems for soil and water. the present study was conducted to introduce walnut shell-based activated carbon (ac) as a new low-cost adsorbent for the removal of cephalexin (cfx) antibiotic from aqueous solutions. materials and methods: this study was conducted in...

in this work, hierarchical wo3 core-shell microspheres were synthesized via a facile template-free precipitation method. gas sensing properties of the synthesized powder to acetone and some other volatile organic compounds were comparatively investigated with commercial wo3 nanoparticles. the synthesized and commercial powders were characterized by x-ray diffraction, scanning electron microscop...

this study aimed to investigate the effects of stiffeners on buckling of thin cylindrical shells under uniform axial compression. to this end, more than 300 finite element models of stiffened cylindrical shells were prepared. the variables considered are shell thickness, number, dimension and the location of the vertical and horizontal stiffeners as well as circular symmetrical imperfections. r...

the photocatalytic coatings were prepared via incorporating the modified titania nanoparticles into epoxy-based inorganic-organic hybrid coatings. titania nanoparticles were first synthesized from tetra-n-butyl titanate using sol-gel methods by two different calcination treatments, i.e., in mild condition (80°c) and 500°c. the formed anatase nanoparticles were further modified as titania-silica...

free vibration of simply supported circular cylindrical shell made of functionally graded material (fgm) under internal pressure was investigated. the effective material properties are assumed to vary continuously along the thickness direction according to a volume fraction power law distribution. first order shear deformation theory based on love's first approximation theory was utilized in th...

in this research controlled coating of magnetite (fe3o4) nanoparticles with sio2 was investigated. the fe3o4 nanoparticles were synthesized via chemical co-precipitation and then coated by silica according to stober method. effects of tetra ethyl ortho silicate (teos) concentration and ethanol to teos on the coating thickness were investigated. x-ray powder diffraction, fourier transform infrar...

surface topography and ultrastructure of dried cysts of artemia parthenogenetica (vedaranyam population) and bisexual artemia sp. (kelambakkam population) were studied electron microscopically in order to identify the bisexual strain, inhabiting covelong salterns, kelambakkam, south india. the scope of this study is to provide substantial information for further characterization of these artemi...

in the present investigation, shells of pistachio are used as adsorbents and they have been successfully used for the removal of blue 56, from water samples. the effect of various parameters such as: ph, amounts of adsorbents, size of adsorbent particles and contact time on removal processing were investigated. in this study freundlich absorption isotherms and langmuir were investigated . the e...

the paper studies optimization of shell-and-tube heat exchangers using the particle swarm optimization technique. a total cost function is formulated based on initial and annual operating costs of the heat exchangers. six variables – shell inside diameter, tube diameter, baffle spacing, baffle cut, number of tube passes and tube layouts (triangular or square) – are considered as the design para...