Papers by Keyword: Pore Size

Abstract: This paper includes analysis on the recent advancement of glass fiber core based vacuum insulation panels (VIPs) in China, including the experimental development of mixed ultrafine fiberglass prototype core material consisting of Centrifugal and Aerocor glass wool mixture at different ratios. Pore sizes exhibited by these prototypes generally range between 15-25μm. Extensive centre of panel thermal conductivity (K_cop) were performed from which thermal performance graphs were extracted and analyzed prudently. K_cop analysis verified superior performance of the prototypes over traditional glass fiber core samples, hinting greater service life. The study concludes that in order to optimize the long term performance of current industrial glass fiber core material reduction of pore size at less than 10μm range as well as reduction of x-z axis fiber orientation angle to less than 450 would potentially decrease core structural sensitivity towards both gaseous and solid conductivity at increase of internal pressure.

Abstract: A flexible, controllable and facile synthesis route was presented in the synthesis of spherical particles of mesoporous SBA-15 with diameter up to 28 nm, and particle diameter of 3-5 µm. The structures and morphology of these materials were characterized by powder X-ray diffraction (XRD), nitrogen adsorption analysis and scanning electron micrographs (SEM). The relationship between the porous property of silica and the weight ratio of starch to TMB were discussed. It indicates that the weight ratio of starch to TMB have a significant effect on the pore size, the surface area and also contribute to a narrow pore size distribution.

Abstract: Mesoporous carbonated hydroxypatite (CHA) is a promising drug delivery agent for disease treatment and could be a carrier for different types of drugs and antibiotics. It is still a challenge to introduce pores to carry drugs within the mesoporous CHA and obtain high surface area nanoparticles. This study investigates the effect of different types of nonionic surfactant and carbonate concentration on the pore characteristic of mesoporous CHA. Mesoporous CHA is synthesised through the coprecipitation technique using nonionic surfactants as pore templates i.e., P123 and F127 with different carbonate concentration. The axial view of transmission electron microscopy (TEM) images shows the pores formed within the particles are distributed randomly, while the parallel view demonstrates that nanopore channels are developed within the CHA particles. Nitrogen adsorption analysis provides the surface area and Pore Size Distribution (PSD) of the nanoparticles. The PSD shows that CHA synthesis with P123 and F127 has similar pore size, around 28.9 nm, but different surface area. The results confirm the different types of surfactant templates has a positive effect on the pore characteristic, while carbonate precursor concentration does not significantly change surface area and pore size.

Abstract: In this work, the influences of process parameters including electroplating time, annealing temperature, etchant concentration and dealloying time on the microstructures of nanoporous copper (NPC) were quantitatively evaluated in terms of pore size. Taguchi method was utilized to reduce the number of experiments required for the evaluation. The effect of each parameter variable on the characterization length scale of NPC was quantified and discussed. It was found that the annealing temperature was the most dominant factor influencing the microstructure of NPC and the dealloying time, electroplating time and etchant concentration contributed sequentially weakly to that of NPC.

Abstract: For the present situation of spotty mask fabrics in current market, the paper used natural fiber silk as raw materials for the study of anti-fog and haze mask fabrics. The paper design five different programs and any one sample in every program has different weft density or warp and weft yarn fabric specifications. Make total of 15 kinds of trial samples and do a series of testing of fabric performance. Through testing the pore size value, the filtration efficiency, resistance value and other indicators and analyzing the results, do research on filtering properties of the fabrics. The conclusions have certain guiding significance in product development.

Abstract: Electrospinning is a versatile and efficient technique for fabricating nanofibrous tissue engineering scaffolds. However, problems such as small pore size of electrospun scaffolds have limited their applications for tissue regeneration. It is important to modify/improve existing electrospinning techniques for fully realizing the potential of both the electrospinning technology and electrospun nanofibrous scaffolds. To increase the pore size of scaffolds prepared by conventional electrospinning technology, in the present study, a hybrid fabrication technique by combining electrospinning with phase separation is utilized. Polymer solutions were made using mixed solvent of (a) DCM and DMF or (b) chloroform and DMF and electrospun fibers were deposited in ice water, ice methanol or liquid nitrogen. It was shown that for poly (ε-caprolactone) (PCL) scaffolds, the hybrid technique could maintain the nanofibrous structure for scaffolds and control the pore size in scaffolds. As compared with pore sizes in PCL scaffolds made by conventional electrospinning, pores were larger in PCL scaffolds produced by the hybrid technique.

Abstract: The work explores feasibility of 3D finite element modeling (FEM) to study the effective linear properties of porous brittle material microstructures represented by a uniform cubic mesh. Both artificial virtually generated and real 3D tomography specimens are considered in this work. A method for assessment of the critical value of tomography resolution is proposed. A method to build approximations of the linear effective structure properties of interest at virtually zero FE size is developed. The methods do not have to be associated with mechanical modeling only but can be applied in some other cases, e.g. effective thermal conductivity or effective permeability calculations.

Abstract: Metal foams are widely produced by using different techniques such as compaction and replication method. In this study, slurry method also known as replication method has been used to produce SS316L foams. SS316L powders (50wt% and 60wt%) were mixed with the binders and distilled water by using mechanical stirrer. Polyethylene Glycol (PEG) and Carboxyl Methyl Cellulose (CMC) were used as binders. Polyurethane (PU) foam was used as scaffold and dipped into SS316L slurry then dried in room temperature for 24 hours. Sintering process has been done in two different temperatures which were 1200°C and 1300°C in vacuum furnace. The morphological study was performed using Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray (EDX). The SEM micrograph showed that the cells were interconnected and the structures become denser as the sintering temperature increase. The average pores size is ranging from 252.8 μm-353.8 μm, while strut size ranging from 50.2 μm-79.9 μm based on SEM micrograph analysis. The elemental analysis from EDX showed the element presence in the SS316L foam remain from SS316L powder which are Chromium (Cr), Nickel (Ni), Molybdenum (Mo), Cooper (Cu), Nitrogen (N₂), Sulphur (S) and Silicon (Si). Higher sintering temperature contributes better grain growth between particles where the point-contact between the particles expanded and disappear the small pores.

Abstract: Mesoporous TiO₂ with high surface area (S_BET) and different pore size was successfully fabricated via hydrothermal method using cetyltrimethylammonium bromide and PEO-PPO-PEO as the structure-directing agents, and tetrabutyl titanate (TBT) as titanium source. S_BET and pore size of the materials were adjusted by using different amount of TBT. S_BET was increased as TBT changing from 0.5 g to 1.0 g, and then dropped as 2.0 g TBT added. Among as-prepared samples (PC), PC-1.0 showed the highest S_BET of 92.72 m² g¹. With the increase amount of TBT, pore size increased from 10.36 nm to 12.72 nm. The phtocatalysis study showed that PC-1.0 had the highest percent degradation of 99.6 %. We believed that the design and synthesis of mesoporous TiO₂ with changing mesopores and S_BET are important for both fundamental and technological viewpoints.

Abstract: Pulverizing problem, low mechanical strength and poor wear resistance of desulfurization sorbent limit the further development and industrialization of hot coal gas desulfurization technology. The present paper highlighted on the recent progress of hot gas desulfurization researches and gave a fully detailed introduction on physical parameters that reflect the texture of desulfurizer: specific surface area, pore volume, pore size and its distribution, porosity, fractal dimension and so on. Different from the traditional physical parameters, fractal dimension, as a comprehensive physical parameter describing a fractal structure, reflects the regularity degree of a porous structure. With the increase of sorbent fractal dimension, the complexity of pore spatial geometrical features increases, and the porosity and average diameter for pore decrease. The specific surface area also increased consequentially with the increase of micro-pore. Besides, this paper also investigated the proper texture of desulfurization sorbent that is favorable for desulfurization process on the basis of desulfurization mechanism for fuel gas.