135 research outputs found
Porosity estimation of Phyllostachys edulis (Moso bamboo) by computed tomography and backscattered electron imaging
This study aims to investigate and quantify the porosity in the cross
section of Phyllostachys edulis (Moso bamboo) culm wall. The porosity results are
expected to be utilised in numerical study of heat and moisture transfer. Computed
tomography (CT) and backscattered electron (BSE) imaging methods are utilised in
this study because these two methods allow measurements of the anisotropic features
of bamboo specimens. The results of these two methods can be represented as
the function of the real dimension rather than the pore size distribution of the
specimen. The specimens are obtained from eight different locations along the
Moso bamboo culms. Both internodes and nodes specimens are measured in this
study. The average porosity, standard deviation (SD) and coefficient of variation
(COV) are calculated for BSE and CT results. Pearson product-moment correlation
coefficient (PPMCC) is also calculated in this study to analyse the correlation
between the BSE results and CT results. Typical porosity results from 400 sampling
points and 10 portions average porosity are analysed in this study. The CT scanning
results show similar trend with BSE results. The correlation relationship between
BSE and CT results approaches moderate correlation level to strong correlation
level. The average porosity of internode specimens is from 43.9 to 58.8 % by BSE
measurement and from 44.9 to 63.4 % by CT measurement. The average porosity of
node specimens is from 37.4 to 56.6 % by BSE measurement and from 32.1 to
62.2 % by CT measurement
Porosity estimation of (Moso bamboo) by computed tomography and backscattered electron imaging
This study aims to investigate and quantify the porosity in the cross section of Phyllostachys edulis (Moso bamboo) culm wall. The porosity results are expected to be utilised in numerical study of heat and moisture transfer. Computed tomography (CT) and backscattered electron (BSE) imaging methods are utilised in this study because these two methods allow measurements of the anisotropic features of bamboo specimens. The results of these two methods can be represented as the function of the real dimension rather than the pore size distribution of the specimen. The specimens are obtained from eight different locations along the Moso bamboo culms. Both internodes and nodes specimens are measured in this study. The average porosity, standard deviation (SD) and coefficient of variation (COV) are calculated for BSE and CT results. Pearson product-moment correlation coefficient (PPMCC) is also calculated in this study to analyse the correlation between the BSE results and CT results. Typical porosity results from 400 sampling points and 10 portions average porosity are analysed in this study. The CT scanning results show similar trend with BSE results. The correlation relationship between BSE and CT results approaches moderate correlation level to strong correlation level. The average porosity of internode specimens is from 43.9 to 58.8 % by BSE measurement and from 44.9 to 63.4 % by CT measurement. The average porosity of node specimens is from 37.4 to 56.6 % by BSE measurement and from 32.1 to 62.2 % by CT measurement
Facile control of silica nanoparticles using a novel solvent varying method for the fabrication of artificial opal photonic crystals
In this work, the Stöber process was applied to produce uniform silica nanoparticles (SNPs) in the meso-scale size range. The novel aspect of this work was to control the produced silica particle size by only varying the volume of the solvent ethanol used, whilst fixing the other reaction conditions. Using this one-step Stöber-based solvent varying (SV) method, seven batches of SNPs with target diameters ranging from 70 to 400 nm were repeatedly reproduced, and the size distribution in terms of the polydispersity index (PDI) was well maintained (within 0.1). An exponential equation was used to fit the relationship between the particle diameter and ethanol volume. This equation allows the prediction of the amount of ethanol required in order to produce particles of any target diameter within this size range. In addition, it was found that the reaction was completed in approximately 2 h for all batches regardless of the volume of ethanol. Structurally coloured artificial opal photonic crystals (PCs) were fabricated from the prepared SNPs by self-assembly under gravity sedimentation
A Two-Step Hydrothermal Synthesis Approach to Monodispersed Colloidal Carbon Spheres
This work reports a newly developed two-step hydrothermal method for the synthesis of monodispersed colloidal carbon spheres (CCS) under mild conditions. Using this approach, monodispersed CCS with diameters ranging from 160 to 400 nm were synthesized with a standard deviation around 8%. The monomer concentration ranging from 0.1 to 0.4 M is in favor of generation of narrower size distribution of CCS. The particle characteristics (e.g., shape, size, and distribution) and chemical stability were then characterized by using various techniques, including scanning electron microscopy (SEM), FT-IR spectrum analysis, and thermalgravity analysis (TGA). The possible nucleation and growth mechanism of colloidal carbon spheres were also discussed. The findings would be useful for the synthesis of more monodispersed nanoparticles and for the functional assembly
Characterization techniques for studying the properties of nanocarriers for systemic delivery
Nanocarriers have attracted a huge interest in the last decade as efficient drug delivery systems and diagnostic tools. They enable effective, targeted, controlled delivery of therapeutic molecules while lowering the side effects caused during the treatment. The physicochemical properties of nanoparticles determine their in vivo pharmacokinetics, biodistribution and tolerability. The most analyzed among these physicochemical properties are shape, size, surface charge and porosity and several techniques have been used to characterize these specific properties. These different techniques assess the particles under varying conditions, such as physical state, solvents etc. and as such probe, in addition to the particles themselves, artifacts due to sample preparation or environment during measurement. Here, we discuss the different methods to precisely evaluate these properties, including their advantages or disadvantages. In several cases, there are physical properties that can be evaluated by more than one technique. Different strengths and limitations of each technique complicate the choice of the most suitable method, while often a combinatorial characterization approach is needed
Optimum Support Properties for Protein Separation by High-Performance Size Exclusion Chromatography
Evaluation of Advanced Silica Packings for the Separation of Biopolymers by High-Performance Liquid Chromatography. I. Design and properties of parent silicas
Influence of the Manufacturing Technique on the Macroâ and Microstructure of Reticulated CarbonâBonded Alumina Foams
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