On model for Darcy–Forchheimer 3D nanofluid flow subject to heat flux boundary condition

Journal of Thermal Analysis and Calorimetry - This paper provides a theoretical study of 3D nanofluid flow with zero nanoparticles mass and constant heat fluxes conditions. An incompressible...     

Characterization of a Multi-responsive Magnetic Graphene Oxide Nanocomposite Hydrogel and Its Application for DOX Delivery

Nanocomposite hydrogels are one of the most important types of biomaterials which can be used in many different applications such as drug delivery and tissue engineering.Incorporation of nanoparticles within a hydrogel matrix can provide unique characteristics like remote stimulate and improved mechanical strength.In this study,the synthesis of graphene oxide and graphene oxide nanocomposite hydrogel has been studied.Nanocomposite hydrogel was synthesized using carboxymethyl cellulose as a natural base,acrylic acid as a comonomer,graphene oxide as a filler,ammonium persulfate as an initiator,and iron nanoparticles as a crosslinking agent.The effect of reaction variables such as the iron nanoparticles,graphene oxide,ammonium persulfate,and acrylic acid were examined to achieve a hydrogel with maximum absorbency.Doxorubicin,an anti-cancer chemotherapy drug,was loaded into this hydrogel and its release behaviors were examined in the phosphate buffer solutions with different pH values.The structure of the graphene oxide and the optimized hydrogel were confirmed by Fourier-transform infrared spectroscopy,Raman spectroscopy,X-ray diffraction,scanning electron microscopy,and atomic force microscopy.     

New sensitive spectrophotometric method for the determination of clomipramine-HCl in pure form and pharmaceutical preparations

A simple, rapid and sensitive spectrophotometric method for the assay of clomipramine-HCl is described. It has been found that clomipramine-HCl reacts with ammonium molybdate in acetic medium to give blue color product exhibiting maximum absorbance at 712 nm. The reaction is selective for clomipramine-HCl with 1 μg/mL as visual limit of detection. It provides a basis for a sensitive spectrophotometric method for the determination of clomipramine-HCl. The method obeys Beer’s Law from 0.001 to 0.250 mg/mL. The standard deviation does not exceed 0.005 mg/mL. The method has been successfully applied to the determination of clomipramine-HCl in pure form and pharmaceutical preparations. The quantitative assessment of tolerable amounts of possible interferants was also studied. The results are reproduced within ±1% and are in good agreement with those obtained by the standard procedure.     

ZnSe-石墨烯/TiO_2声催化剂上罗丹明B降解与反应氧物种生成(英文)

Nanostructured ZnSe-graphene/TiO2 was synthesized by a hydrothermal-assisted approach. ZnSe-graphene/TiO2 exhibited favorable adsorption of rhodamine B, a wide wavelength absorption range, and efficient charge separation. Reactive oxygen species were generated by the oxidation of 1,5-diphenyl carbazide to 1,5-diphenyl carbazone. The sonocatalytic reaction mechanism was pro-posed. These findings potentially broaden the applications of sonocatalytic technologies.     

Evaluation of a novel nanocrystalline hydroxyapatite powder and a solid hydroxyapatite/Chitosan-Gelatin bioceramic for scaffold preparation used as a bone substitute material

Artificially fabricated hydroxyapatite (HAP) shows excellent biocompatibility with various kinds of cells and tissues which makes it an ideal candidate for a bone substitute material. In this study, hydroxyapatite nanoparticles have been prepared by using the wet chemical precipitation method using calcium nitrate tetra-hydrate [Ca(NO₃)₂.4H₂O] and di-ammonium hydrogen phosphate [(NH₄)₂ HPO₄] as precursors. The composite scaffolds have been prepared by a freeze-drying method with hydroxyapatite, chitosan, and gelatin which form a 3D network of interconnected pores. Glutaraldehyde solution has been used in the scaffolds to crosslink the amino groups (|NH₂) of gelatin with the aldehyde groups (|CHO) of chitosan. The X-ray diffraction (XRD) performed on different scaffolds indicates that the incorporation of a certain amount of hydroxyapatite has no influence on the chitosan/gelatin network and at the same time, the organic matrix does not affect the crystallinity of hydroxyapatite. Transmission electron microscope (TEM) images show the needle-like crystal structure of hydroxyapatite nanoparticle. Scanning Electron Microscope (SEM) analysis shows an interconnected porous network in the scaffold where HAP nanoparticles are found to be dispersed in the biopolymer matrix. Fourier transforms infrared spectroscopy (FTIR) confirms the presence of hydroxyl group (OH^-) , phosphate group (PO^3-₄) , carbonate group (CO^2-₃) , imine group (C=N), etc. TGA reveals the thermal stability of the scaffolds. The cytotoxicity of the scaffolds is examined qualitatively by VERO (animal cell) cell and quantitatively by MTTassay. The MTT-assay suggests keeping the weight percentage of glutaraldehyde solution lower than 0.2%. The result found from this study demonstrated that a proper bone replacing scaffold can be made up by controlling the amount of hydroxyapatite, gelatin, and chitosan which will be biocompatible, biodegradable, and biofriendly for any living organism.     

Loss of atom interference due to a random phase

We suggest a model where the influence of an environment on the atom interference is associated with a random phase. The model consists of sending a two-level state atom through two cavities, both containing a standing wave field in the Bragg regime and Raman–Nath regime, respectively. In view of this model, we can visualize the loss of interference fringes if the randomness of the phase increases, and the restoration of the pattern when it decreases, as which-path information. Then, the controllable random noise acts as a decoherence that would destroy the quantum features.     

Differential equation approach for the energy average of the scattering function

An exact differential equation is given to evaluate the energy average of the scattering function. The advantage of the differential equation as compared to the earlier methods based on series expansion is that one has to evaluate only single sums over the complex poles of the S-matrix. Using Wigner’s semicircle law for the distribution of the real parts of the poles of the scattering matrix, the earlier expression for the energy average of the scattering function is rederived.     

On an integral over the surface ofN-dimensional unit sphere

An integral which occurs in the new matrix ensembles and the width fluctuation factor is evaluated using a transformation which changes a Gaussian into an exponential. It is expressed in the form of a series whose terms are found using a simple recursion relation. It is shown that the series can be summed in closed form for the two-dimensional case.