arXiv subjects

M. Moradi

Publications and source records attributed to M. Moradi.

7 recordsLinked to original sources

arXiv2026

Controlled drug delivery from chitosan-coated heparin-loaded nanopores anodically grown on nitinol shape-memory alloy

Nitinol (NiTi shape-memory alloy) is an interesting candidate in various medical applications like dental, orthopedic, and cardiovascular devices, owing to its unique mechanical behaviors and proper biocompatibility. The aim of this work is the local controlled delivery of a cardiovascular drug, heparin, loaded onto nitinol treated by electrochemical anodizing and chitosan coating. In this regard, the structure, wettability, drug release kinetics, and cell cytocompatibility of the specimens were analyzed in vitro. The two-stage anodizing process successfully developed a regular nanoporous layer of Ni-Ti-O on nitinol, which considerably decreased the sessile water contact angle and induced hydrophilicity. The application of the chitosan coatings controlled the release of heparin mainly by a diffusional mechanism, where the drug release mechanisms were evaluated by the Higuchi, first-order, zero-order, and Korsmeyer-Pepass models. Human umbilical cord endothelial cells (HUVECs) viability assay also showed the non-cytotoxicity of the samples, so that the best performance was found for the chitosan-coated samples. It is concluded that the designed drug delivery systems are promising for cardiovascular, particularly stent applications.

physics.bio-ph↗

arXiv2020

Extraction a Formalism for Fluids with Non-Spherical Molecules based on the Cluster Expansion of the Energy Functional

In this work, based on the cluster expansion of the energy functional, we have extracted a formalism for calculation of the thermodynamic properties of fluids with non-spherical molecules. The salient feature of the extracted formalism is that it has no restrictions on the type of interaction. In fact our formalism can be employed for all types of realistic inter-particle interactions. Here, for the interaction of two anisotropic molecules, we have applied the Gay-Berne potential. Finally, we have applied this formalism to calculate some thermodynamic properties of fluid H_2 which shows some expected results.

cond-mat.soft↗

arXiv2017

The study of uniaxial-biaxial phase transition of confined hard ellipsoids using density functional theory

The density profiles and corresponding order parameters of the hard ellipsoids confined between two hard walls and also in contact with a single hard wall are studied using the density functional theory. The Hyper-Netted Chain (HNC) approximation is used to write excess grand potential of the system with respect to the bulk value. To simplify the calculations we use restricted orientation model (ROM) for the orientation of ellipsoids to find the density profiles and order parameters. Density functional theory shows that there is a uniaxial-biaxial phase transition near a single hard wall and also between two hard walls for a fluid consisting of uniaxial hard ellipsoidal particles with finite elongation.

cond-mat.soft↗

arXiv2017

Rheology of active suspensions with hydrodynamic interactions

Using a simple model of self-propelled particle, the effective shear viscosity of a dilute, spatially homogeneous suspension of active particles is studied. We use formulation of non-linear Fokker-Planck equation to drive a kinetic description, including the effect of external flow field, rotary diffusion, and particle-particle hydrodynamic interactions in two dimensions. Analytical expressions are obtained for the stress tensor at small Peclet numbers, in a simple shear flow, up to second order of volume fraction of the swimmers, which shows the explicit dependence of shear viscosity on the details of the swimming mechanism.

cond-mat.soft↗

arXiv2016

Enhanced Performance of Dye-Sensitized Solar Cells based on TiO2 Nanotube Membranes using Optimized Annealing Profile

We use free-standing TiO2 nanotube membranes that are transferred onto FTO slides in front-side illuminated dye-sensitized solar cells (DSSCs). We investigate the key parameters for solar cell arrangement of self-ordered anodic TiO2 nanotube layers on the FTO substrate and namely the influence of the annealing procedure on the DSSC light conversion efficiency. The results show that using an optimal temperature annealing profile can significantly enhance the DSSC efficiency (in our case 9.8 %), as it leads to a markedly lower density of trapping states in the tube oxide, and thus to strongly improved electron transport properties.

cond-mat.mtrl-sci↗

arXiv2016

Orientational ordering of confined hard rods: the effect of shape anisotropy on surface ordering and capillary nematization

We examine the ordering properties of rectangular hard rods with length L and diameter D at a single planar wall and between two parallel hard walls using the second-virial density functional theory. The theory is implemented in the three-state Zwanzig approximation, where only three mutually perpendicular directions are allowed for the orientations of hard rods. The effect of varying shape anisotropy is examined at L/D=10, 15 and 20. In contact with a single hard wall, the density profiles show planar ordering, damped oscillatory behavior, and wall induced surface ordering transition below the coexisting isotropic density of bulk isotropic-nematic (I-N) phase transition. Upon approaching the coexisting isotropic density, the thickness of nematic film diverges logarithmically, i.e. the nematic wetting is complete for any shape anisotropy. In the case of confinement between two parallel hard walls, it is found that the continuous surface ordering transition depends strongly on the distance between confining walls (H) for H L. The minimal density at which a surface ordering transition can be realized is located at around H~2D for all studied shape anisotropies due to the strong interference effect between the two hard walls. The first order I-N phase transition of the bulk system becomes surface ordered isotropic (IB)-capillary nematic (NB) phase transition in the slit pore. This first order IB-NB transition weakens with decreasing pore width and terminates in a critical point for all studied shape anisotropies.

cond-mat.soft↗

arXiv2004

On the Probability of Occurrence of Clusters in Abelian Sandpile Model

We have performed extensive simulations on the Abelian Sandpile Model (ASM) on square lattice. We have estimated the probability of observation of many clusters. Some are in good agreement with previous analytical results, while some show discrepancies between simulation and analytical results.

cond-mat.stat-mech↗