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.

Anti-fouling and permeable polyvinyl chloride nanofiltration membranes embedded by hydrophilic graphene quantum dots for dye wastewater treatment

Abstract: In recent years, graphene has received much attention in many fields, to the extent that it has been mostly able to solve the tremendous human challenge of water scarcity. In this research, graphene quantum dots (GQDs) were used for the preparation of polyvinyl chloride (PVC) blended matrix nanofiltration membrane for removing Reactive Blue 19 dye wastewater. Improvement in anti-fouling performance was tested by filtration of bovine serum albumin (BSA) solution. The GQDs were synthesized and characterized using TEM, XRD, FTIR, UV-Vis spectrophotometer, and fluorescence emission. The surface morphology of prepared nanocomposite membranes was identified using AFM and SEM images. By embedding the optimum amount of the GQDs to the PVC matrix (1 wt%), the water flux reached 19.1 L/m2 h, which is 56% higher than the unfilled membrane. In the case of anti-fouling properties, the flux recovery ratio was improved from 68.8 to 80.0%. All of the fabricated PVC membranes have BSA rejection of more than 98%, and Reactive Blue 19 dye rejection of more than 96%. It can be concluded that the organic anti-fouling characteristics were improved with considerable permeability enhancement without influencing membrane rejection performance.

Green Synthesis of CdSe Colloidal Nanocrystals with Strong Green Emission by the Sol–Gel Method

Abstract: In this paper, high-quality CdSe colloidal nanocrystals were synthesized by an improved Sol–Gel green technique. These colloidal nanocrystals were characterized by different techniques: Transmission Electron Microscopy (TEM) showed that the diameter of colloidal nanocrystals is about 3 nm; X-ray diffraction (XRD) demonstrated that CdSe colloidal nanocrystals formed in cubic phase; Fourier Transform Infrared spectroscopy (FT-IR) was employed to study the chemical compounds of as-prepared sol; UV–visible absorption spectroscopy was used to evaluate optical properties of prepared CdSe colloidal nanocrystals, which indicated that the absorption peak is around 500 nm; Photoluminescence (PL) spectroscopy demonstrated that quantum yields for colloidal nanocrystals are 50.2% with 440 nm excitation wavelengths. Experimental observation has shown that highly stable CdSe colloidal nanocrystals with a strong green emission were synthesized. The mentioned optical properties have not been reported before.

Effect of penconazole and drought stress on the essential oil composition and gene expression of Mentha pulegium L. (Lamiaceae) at flowering stage

Abstract: Effect of penconazole (PEN) on the expression level of two genes in the biosynthesis pathway of monoterpenes, isopiperitenone reductase (iPR) and pulegone reductase (PR), and essential oil (EO) compounds were studied at flowering stage of Mentha pulegium L. under drought stress. Plants were grown with different levels of field capacity (100 and 50 %) with or without PEN (15 mg l−1). Results showed that drought stress decreased the growth and productivity parameters. PEN treatment to drought-stressed plants decreased the negative effects of drought stress on these parameters. The EO yield increased by about 1.6 times under drought stress, and the highest amount of EO was obtained in drought-stressed with PEN. Drought stress increased pulegone and decreased menthone percentage, and the highest pulegone percentage (78.2 % of total constituents) was obtained in drought-stressed with PEN treatment. Semi-quantitative RT-PCR showed drought stress increased the expression level of iPR and PR genes. PEN treatment promoted the impact of drought stress on iPR gene expression and repressed PR gene expression. Our results suggest that PEN may be a useful tool for the regulation of monoterpene metabolism in M. pulegium under stress condition.

PFLUA-DIoT: A Pairing Free Lightweight and Unlinkable User Access Control Scheme for Distributed IoT Environments

Abstract: The Internet of Things (IoT) connects enormous objects through various sensors to facilitate daily life by interconnecting the information space with the decision-makers. Security and privacy are, however, the main concerns in IoT due to the openness of communication channels and the unattended nature of common sensors. To provide security and privacy for sensors and users in IoT-based systems; in 2019, Zhou et al. proposed an unlinkable authentication scheme using bilinear pairings. However, the vulnerability of their scheme against sensor node impersonation attack as proved in this article renders the scheme of their work impractical and insecure. A pairing free lightweight and unlinkable authentication scheme for distributed IoT devices (PFLUA-DIoT) is then proposed in this article. The security of PFLUA-DIoT is proved using the formal method along with a discussion on its provision of security features. The performance and security comparisons show that PFLUA-DIoT provides known security features and provides better performance. Due to the avoidance of bilinear pairing-based expensive operations, PFLUA-DIoT completes authentication in less than half running time as compared with their and related schemes. Therefore, the PFLUA-DIoT can address the security and privacy issues of IoT, practically and efficiently.