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Water absorption and diffusion characteristics of nanohydroxyapatite (nHA) and poly(hydroxybutyrate-co-hydroxyvalerate-) based composite tissue engineering scaffolds and nonporous thin films
No full textWater uptake characteristics of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV-) based composite tissue engineering (TE) scaffolds incorporating nanosized hydroxyapatite (nHA) have been investigated. The water absorption of these composite scaffolds obeyed the classical diffusion theory for the initial period of time. The diffusion coefficients of the composite scaffolds during the water absorption were much faster than those for the nonporous thin films, suggesting that the water uptake process depends on the presence of porosity and porous microstructure of the composite scaffolds. The incorporation of nHA increased the water uptake of both the composite scaffolds and thin films. It was also observed that the equilibrium uptake increased with the incorporation of nHA. This increase in the water uptake was largely due to the nHA particle aggregates in the microstructure of both composite scaffolds and thin films. The activation energy for diffusion was also determined using the Arrhenius equation for both porous scaffolds and thin films and the results suggested that the activation energy for scaffolds was lower than that for thin films. © 2013 Naznin Sultana and Tareef Hayat Khan
Fabrication techniques and properties of scaffolds
No full textThe development of porous materials for use as scaffolds for the sustained 3D growth of tissue is a fast growing area in TE that has attracted commercial interest to a large extent. To fabricate both polymer scaffold and composite scaffold, many techniques are available. By using proper technique, the porous structure of polymeric and composite scaffolds could be controlled by varying the processing or formulation parameters. It is often necessary to modify the surface properties of biomaterials without changing the bulk attributes as a biomaterial rarely possess good surface characteristics suitable for bone tissue engineering. This chapter reviews the various existing methodologies to fabricate scaffolds and to modify the surface properties of scaffolds. It also discusses the study of interactions between tissues and biomaterials
Automatic generation of cobie data from revit
No full textAs the usage of BIM increased in the construction industry, some construction owners started exploring the use of BIM for maintaining their facilities. Construction Operations Building Information Exchange (COBIE), a spreadsheet data format suggested in 2007 to manipulate building information, is considered as one of the solutions that would facilitate the process of transferring information from BIM to applications for facilities management. Several BIM and Computer Aided Facilities Management (CAFM) applications offer functions to export or import the COBIE data. To facilitate the process of generating the COBIE data out of Building Information Model, some add-in applications, such as COBIE Toolkit for Revit, also were developed. However, most of these applications handle a limited amount of COBIE data. Professionals using these add-in applications therefore sometimes end up spending a significant amount of time to add additional data manually to the COBIE data file. To automatically get a data-rich COBIE file, we developed a prototype application that extracts information from Revit, which is one of the BIM authoring tools, stores them in an external database, and then produces the COBIE file using information stored in the database. We applied our application to a pilot project and produced 8 COBIE worksheets automatically, which demonstrated a significant amount of time saving. This paper presents how our prototype application produces 8 COBIE data sets automatically. It also addresses our attempt to handle more COBIE data sets
Generalised Separable Solution of Double Phase Flow through Homogeneous Porous Medium in Vertical Downward Direction Due to Difference in Viscosity
Get PDFIn this paper the instability (fingering) phenomenon in a double phase immiscible (oil and water) flow through the homogeneous porous medium with mean capillary pressure in the vertical downward direction is discussed. The mathematical formulation of this problem yields a nonlinear partial differential equation and the generalised separable solution is given in the exponential form. The numerical solution and graphical presentation is given using MAT LAB coding
Application of Fractional Moments for Comparing Random Variables with Varying Probability Distributions
Get PDFNew methods are being presented for statistical treatment of different random variables with unknown probability distributions. These include analysis based on the probability circles, probability ellipses, generalized mean values, generalized Pearson correlation coefficient and the beta-function analysis. Unlike other conventional statistical procedures, the main distinctive feature of these new methods is that no assumptions are made about the nature of the probability distribution of the random series being evaluated. Furthermore, the suggested procedures do not introduce uncontrollable errors during their application. The effectiveness of these methods is demonstrated on simulated data with extended and reduced sample sizes having different probability distributions
A Note on the Qualitative Behavior of Some Second Order Nonlinear Equation
Get PDFIn this paper, we present two qualitative results concerning the solutions of some second order nonlinear equations, under suitable assumptions. The first result centers on the boundedness of the solutions while the second discusses the square integrability of the solutions. These results are obtained by extending and improving the current literature through sound mathematical analysis
Robust switched filtering for time-varying polytopic uncertain systems
No full textThis paper studies the problem of designing robust switched filters for time-varying polytopic uncertain systems. The synthesis conditions for a set of filters under a min-switching rule are derived to guarantee globally asymptotical stability with optimized robust H∞ performance. Specifically, the conditions are expressed as bilinear matrix inequalities (BMIs) and can be solved by linear matrix inequality (LMI) optimization techniques. The proposed approach utilizes a piecewise quadratic Lyapunov function to reduce the conservativeness of robust filtering methods based on single Lyapunov function, thus better H∞ performance can be achieved. Both continuous and discrete-time robust filter designs are considered. To simplify filter implementation, a method to remove redundancy in min-switching filter members is also introduced. The advantages of the proposed robust switching filters are illustrated by several examples. © 2013 by ASME
Comparative study of three Plumbago L. species (Plumbaginaceae) by microscopy, UPLC-UV and HPTLC
No full textThis paper presents a comparative study of anatomy of leaves, stems and roots of three species of Plumbago, namely P. auriculata Lam., P. indica L. and P. zeylanica L. by light microscopy. The paper also provides qualitative and quantitative analysis of the naphthoquinone, plumbagin - a major constituent present in these species - using UPLC-UV. Microscopic examinations revealed the presence of distinctive differences in the anatomical features of the leaf, stem and root of the three species, and these can thus be used for identification and authentication of these species. UPLC-UV analysis showed the highest concentration of plumbagin in the roots of P. zeylanica (1.62 % w/w) followed by the roots of P. indica (0.97 % w/w) and then P. auriculata (0.33-0.53 % w/w). In contrast, plumbagin was not detected in the stems and leaves of P. indica and in the leaves of P. auriculata, whereas very low concentrations (\u3c0.02 % w/w) of plumbagin were detected in the stems and leaves of P. zeylanica and in the stems of P. auriculata. HPTLC fingerprints of the leaf and root of the three species exhibited distinguishable profiles, while those of the stems were undifferentiated. © 2012 The Japanese Society of Pharmacognosy and Springer Japan