New Nano-Bioactive Glass/Magnesium Phosphate Composites by Sol-Gel Route for Bone Defect Treatment

Silicon - This work was mainly aimed to synthesize new ceramic composites based on nano-bioactive glass (nBG) and magnesium phosphate ceramic (MgP) with different ratios using the sol-gel approach...     

Electrical properties of NiO films obtained by high-temperature oxidation of nickel

Nickel oxide thin films are formed by high-temperature oxidation of nickel foils at 973 K, and are characterized using X-ray diffraction and scanning electron microscopy indicating the formation of a single NiO phase whose thickness grows following a parabolic law. The electrical properties of the formed films are examined by impedance spectroscopy at room temperature; and by measuring direct current (DC) and alternating current (AC) conductivities and dielectric properties at different temperatures. At room temperature, the conductivity is about 4 orders of magnitude higher than that of NiO single crystals. Below 200 K, DC conductivity displays a slight increase with increasing temperature indicating conduction by thermal activation hopping of small polarons. Above 250 K, large polaron conduction associated with holes in the 2p band of O²⁻ with activation energy of about 0.4 eV is observed. Frequency as well as temperature dependencies of the AC conductivity and dielectric constant exhibit trends usually observed in carrier dominated dielectrics.     

A model for supersaturation and aspect ratio for growth dominated crystallization from solution

A model for predicting supersaturation, crystal growth rate, crystal size distribution, and aspect ratio is presented. The model applies to isothermal anti‐solvent crystallization where crystal growth is the dominant phenomena and for systems where crystal habit can be characterized by two‐dimensional variables. A parameter estimation algorithm was derived to extract solute integration coefficients in the two growth directions from experimental data about temporal evolution of concentration during crystallization, the final aspect ratio, and the aspect ratio at the end of the seed age period. Model's predictions for supersaturation and aspect ratio were in good agreement with experimental data obtained on an investigational drug that crystallizes in the parallelepipedic shape. Finally, model simulations predict that for a given initial seed size, the seed loading is the main factor impacting the final aspect ratio and thus identified the range of seed loading that would result in undesired powder flow. © 2015 American Institute of Chemical Engineers AIChE J, 61: 4456–4469, 2015     

Discussion on Barbalat Lemma extensions for conformable fractional integrals

In this paper, the Barbalat-type lemmas for conformable fractional order integrals which can be used to conclude the convergence of a function to zero is discussed.     

The effect of hot water setting treatment on the dyeing properties of grafted polyamide 6.6 microfibres

Polymeric fibres are semicrystalline structures in which macromolecules are rarely oriented in their equilibrium state. Further instabilities are imparted when the fibres are converted into yarns and the yarns into fabrics. Heat setting is an important industrial process, as it reduces the fibre strain to an acceptable limit. Although this process provides dimensional stability to polyamide 6.6, yet it affects its dyeability. This paper investigates the effects of hot water setting treatment on the dyeing properties of grafted polyamide 6.6 microfibres dyed with a cationic dye. It reveals that the dye uptake of the hot water-set samples is inferior to those unset. A kinetic study showed a change in the build-up rate. In addition, an increase in the percentage of grafting improved the quantity of the dye fixed on both unset and hot water-set samples. Comparing the wash fastness of the unset samples, the hot water ones are found to be lower. The modelling of the adsorption isotherms using Langmuir, Freundlich and Jossen relations allows the determination of isotherm constants. The results obtained have been modelled using standard adsorption isotherms.     

Deinking Sludge: A New Biofiller for HDPE Composites

This paper studies the potential of deinking sludge as a biofiller in high-density polyethylene composites. The physicochemical properties of deinking sludge were investigated by X-ray, Fourier transform infrared, thermogravimetric analysis, scanning electron microscopy, and fiber quality analyses. Deinking sludge/high-density polyethylene formulations were produced according to an experimental design. Variables were deinking sludge wt% (5, 12.5, and 20) and maleic anhydride polypropylene content (2 and 4%). The influences of deinking sludge and maleic anhydride polypropylene on the mechanical and morphological properties of deinking sludge/high-density polyethylene composites were investigated. Rigidity and tensile strength increased with fillers content. Maleic anhydride polypropylene ameliorated interfacial interaction and the dispersion of deinking sludge. Maximum properties were predicted at 3.5% of maleic anhydride polypropylene and 15.8% of deinking sludge.     

Fluoride activates G protein-dependent and -independent pathways in dispersed intestinal smooth muscle cells

The existence of G protein-dependent and -independent mechanisms activated by sodium fluoride was examined in muscle cells isolated separately from the circular and longitudinal layers of guinea pig intestine. The cells were transiently permeabilized by incubation with Trans. Port Reagent in the presence or absence of GDP beta S (100 microM) and then re-sealed. In the absence of GDP beta S, NaF (1 mM) induced contraction and caused an increase in [Ca2+]i, IP3 and diacylglycerol levels and in protein kinase C (PKC) activity in both cell types. In the presence of GDP beta S, the increases in IP3, DAG and PKC were abolished whereas contraction and the increase in [Ca2+]i were partly inhibited. Residual contraction and [Ca2+]i were abolished by the Ca2+ channel blocker, methoxyverapamil. We conclude that contraction and Ca2+ mobilization induced by NaF is mediated by G protein activation as well as by a G protein-independent mechanism involving activation of plasmalemmal Ca2+ channels.     

Modeling surface effects on hydrogen permeation in metals

A new mathematical model for analyzing hydrogen permeation in solids, in which surface effects and traps influence hydrogen transport, is presented and solved. The new model combines the McNabb and Foster equations for diffusion with concomitant trapping^[1] and a surface-limited mass-transfer boundary condition. An important result of the new model is the introduction of a new variable,h _m, which is defined as the surface-limited mass-transfer coefficient. Theh _m coefficient can account for all possible surface effects and may be experimentally evaluated.