Kharazmi University

About: Kharazmi University is a education organization based out in Tehran, Iran. It is known for research contribution in the topics: Membrane & Supply chain. The organization has 3395 authors who have published 5321 publications receiving 45645 citations. The organization is also known as: Tarbiat Moallem University of Tehran & Teacher Training University.

A local reproducing kernel method accompanied by some different edge improvement techniques: application to the Burgers’ equation

Abstract: The paper introduces a local reproducing kernel method based on spatial trial space spanned by the Newton basis functions in the “native” Hilbert space of the reproducing kernel. It is a truly meshless approach which uses the local sub clusters of domain nodes, named local domains of influence, for the calculation of the spatial partial derivatives. With the selected domain of influence, an approximation function is introduced as a sum of weighted local Newton basis functions. Then the collocation approach is used to determine weights. After the successful approximation function creation, all the needed differential operators can be constructed by applying an arbitrary operator on the approximation function. The main advantage of using the local method is that the overlapping domains of influence results in many small matrices with the dimension of the number of nodes included in the domain of influence for each center node, instead of a large collocation matrix, and hence the sparse global derivative matrices from local contributions. So the method needs less computer storage and flops. The method leads to a system of ordinary differential equations (ODEs) for the time-dependent partial differential equations (PDEs). This method can be implemented on a set of uniform or random nodes, without any a priori knowledge of node to node connectivity. We have chosen uniform nodal arrangement due to their suitability and better accuracy. To decrease accuracy degradations near boundaries, some different edge improvement techniques are also used. The method is tested on four benchmark problems on Burgers’ equation with mixed boundary conditions. Five nodded domains of influence are used in the local support. The numerical results for different value of Reynolds numbers (Re) is compared with analytical solution as well as some other numerical methods. It is shown that the proposed method is efficient, accurate and stable for flow with reasonably high values of Re.

Application of concrete surfaces as novel substrate for immobilization of TiO2 nano powder in photocatalytic treatment of phenolic water

Abstract: In this study, concrete application as a substrate for TiO2 nano powder immobilization in heterogeneous photocatalytic process was evaluated. TiO2 immobilization on the pervious concrete surface was done by different procedures containing slurry method (SM), cement mixed method (CMM) and different concrete sealer formulations. Irradiation of TiO2 was prepared by UV-A and UV-C lamps. Phenolic wastewater was selected as a pollutant and efficiency of the process was determined in various operation conditions including influent phenol concentration, pH, TiO2 concentration, immobilization method and UV lamp intensity. The removal efficiency of photocatalytic process in 4 h irradiation time and phenol concentration ranges of 25–500 mg/L was more than 80 %. Intermediates were identified by GC/Mass and spectrophotometric analysis. According to the results, photocatalytic reactions followed the pseudo-first-order kinetics and can effectively treate phenol under optimal conditions.

Suspended graphene oxide nanoparticle for accelerated multilayer osteoblast attachment.

Abstract: Mimicking bone tissues having layered structures is still a significant challenge because of the lack of technologies to assemble osteoblast cell types into bone structures. One of the promising and attractive materials in biomedical and different engineering fields is graphene and graphene-based nanostructures such as graphene oxide (GO) because of their unique properties. In most studies, GO was synthesized using chemical vapor deposition method, and was coated on the substrate. In this study, we proposed a simple technique for assembly of cells that facilitates the construction of osteoblast-like structures using suspended GO synthesized by graphite powder, H2 SO4 , and KMnO4 .Toxicity effects of GO on human mesenchymal stem cells (hMSCs) derived from bone marrow were analyzed. In addition to normal MSCs, toxicity effects of GO on human cancer cell line saos-2 as an abnormal cell line that possess several osteoblastic features, was examined. The attachment and expression of osteoblast cells genes were evaluated after differentiation of MSCs to osteoblast cells in presence of suspended GO by scanning electron microscopy and real time PCR. We found that the toxicity effects of GO are dose dependent and in oseogenic medium containing suspended GO the expression level of osteoblast genes osteopontin and osteocalcin and cell adhesion markers connexin were higher than control group. Interestingly, through this method GO was found to induce multilayer osteoblast cell morphology and enhance the number of cell layer. We expect that the presented method would become a highly useful approach for bone tissue engineering. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 293-303, 2018.