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When a cementitious material is in contact with ambient air, CO2 enters the material by the porous network and through the cracks, reacts with the CSH hydrates and Ca (OH)2. These carbonation react...

Chitosan/nanodiopside/nanohydroxyapatite (CS/nDP/nHAp) composite scaffolds were prepared from the mixture of chitosan, nDP, and nHAp in different inorganic/organic weight ratios by using the freeze-drying method. The prepared nHAp and composite scaffolds were investigated using BET, TG, FT-IR, SEM, EDS, and XRD techniques. The composite scaffolds had 50–85% porosities with interlinked porous networks. Moreover, investigation of the cell proliferation, adhesion, and viability using MTT test, and mouse preosteoblast cell proved the cytocompatibile nature of the composite scaffolds with improved cell attachment and proliferation. All these results essentially illustrated that this composite could be a potential for bone tissue engineering applications.

Wicking is an important characteristic which determines the moisture management of the textile products, and thereby has a large impact on comfort. Different techniques have been used to examine the longitudinal or in-plane flow behaviour of the liquid in the porous network of the fibrous assemblies. This paper describes one between several methods to study longitudinal wicking of liquid in textiles. The manuscript presents a detailed explanation of the design and development of an instrumental set-up for wicking measurement. This is based on electrical capacitance principle according to which the capacitance of a parallel plate capacitor varies as dielectric material between the plates changes. It has been aimed to analyse in-plane wicking which includes both horizontal and vertical wicking behaviour in textiles. Several parallel plate capacitors are used to obtain flow property of the liquid on the plane of the fabric in different directions. Many wicking parameters, such as the nature of fluid transpor...

International audience; We report here a simple algorithm to create 2D lattice-based models of porous deposits of preformed nano-metric particles, by mimicking to some extent the physics of the actual deposition/aggregation mechanism. The heterogeneous porous networks obtained exhibit anisotropic properties unlike lattice-based models of porous materials in the existing literature, such as those of porous Vycor glass. We have then used calculations based on the mean field kinetic theory, in order to study the thermodynamics and dynamics of fluid adsorption and desorption in these lattice based porous models. We showcase the influence of pore heterogeneity on the phase equilibrium of the confined fluid, studying both heterogeneity in pore size distribution and chemical heterogeneity of the internal surface.

Nanofibrous interconnected networks have been fabricated from PLA and PET using two different techniques, namely, electrospinning and the concept of microfibrillar composite (MFC), to compare the morphology, production methods, costs, and, to an extent, their potential as scaffolds. Both methods of production create a three-dimensional network, with the electrospun scaffolds being comprised of a fibrillar, cross-plyed structure compared to the extruded scaffolds that consist of an interconnected porous network. The average diameter of the fibers ranged from 125–145 nm and 70–75 nm for the electrospun and extruded scaffolds, respectively. Mouse osteoblastic MC3T3-E1 cells have been used to test the biocompatibility of the electrospun scaffolds. A live/dead stain indicated that cells could attach and grow on the PLA and PET scaffolds. A preliminary cost analysis demonstrates that electrospinning is substantially more time and cost effective for larger quantities produced; however, the MFC technique can pote...

Mechanical alloying and sintering were used to fabricate nanostructured Ti6Al4V scaffolds of highly controllable pore geometry and fully interconnected porous network. Elemental powders were milled for different periods of time (10, 20, 30, 40 and 60 h), mixed with 40–60 vol.-% of 200–400 μm cuboidal NaCl, compacted at 500–600 MPa and sintered according to single or double stage heat treatment regimes at 790 and 950°C under vacuum. After sintering, the samples were soaked in distilled water to washout the NaCl. Foamy microstructures were obtained showing well shaped biopores and fragmentary embedded micropores. The shape of initial NaCl was copied into the biopores which had highly interconnected architecture considered suitable for cancellous bone tissue adherence and cell culture.

A novel heterobimetallic La-Na coordination polymer [La2(odpa)2Na2(H2O)3]n (H4odpa= 2,2′,3,3′ -oxydiphthalic acid) was synthesized under mild condition and characterized by single-crystal X-ray diffraction. Its X-ray crystal structure shows that the new coordination polymer belongs to a monoclinic system, C2/c space group. The crystallographic data are: a = 31.451(2) A, b = 12.635(5) A, c= 8.986(7) A, α = γ = 90°, β = 102.54(8)°. In this complex, it presents a three-dimensional structure containing a 1D {LaO9} chain and 2D Na-odpa layer, which have not been reported in all coordination polymers of odpa ligand.

An extensive experimental investigation of microstructural changes in granites under freeze–thaw cycles using permeability and P-wave velocity measurements is described. Two types of natural granite rocks are considered and tested under dry and saturated conditions. The specimens were subjected to 200 heating–cooling cycles (− 20°C/ + 20°C); each cycle had a duration of 24 h. The results indicate that the ageing process decreases the permeability and the P-wave velocity. The reduction in P-wave velocity is likely to be due to microcrack development (material damage). In dry samples, the microcracks result from the repeated differential contraction–dilatation of the mineral components. In water-saturated samples, there is an additional effect of freezing and thawing of water in the porous network. The decrease in permeability in the dry samples is due to partial closure of existing microcracks. In water-saturated samples, there was no increase in the permeability. A physically acceptable explanation is tha...

In the freeze-drying process, the freezing step is one of the most important steps which determines the texture of the frozen material and, consequently, the final morphological characteristics of the freeze-dried material and its biological activity and its stability. As a matter of fact, the parameters of the freezing protocol have a direct effect on the pore size distribution and on the pore connectivity of the porous network of the freeze-dried matrix. Thus, the ice crystal morphology determines indirectly the mass and the heat transfer rates through the dry layer and, consequently, the freezing parameters have a strong influence on the total duration of the primary and secondary sublimation steps. The main objective of this study was to adapt and to develop a new optical direct microscopy method, based on the reflected flux differences, with episcopic axial lighting to characterize the structure of the different phases of a standard pharmaceutical matrix used for pharmaceutical proteins free...

A Monte Carlo simulation study has been made of adsorption and desorption of a gas in a semiflexible porous network with a porosity of over 95%, which is comparable with that of silica aerogels. Although dilute, the network has substantial effects on the properties of confined fluids. Network flexibility is shown to make a significant difference to both the adsorption/desorption isotherms and the fluid phase coexistence when compared with the case where the network is rigid. For one of the systems studied the solid volume changes by as much as 30% during desorption. This is qualitatively similar to an effect seen in nitrogen adsorption/desorption in some silica aerogels.