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Preparation of Nanobiocomposites Based on Halloysite Nanotubes-Zein and Evaluation of their Performance for Thin Film Microextraction

, M.Sc. Thesis Sharif University of Technology Gordan, Hasti (Author) ; Bagheri, Habib (Supervisor)

Abstract

In this work, a biocompatible sorbent based on halloysite nanotubes-zein bionanocomposite for direct-immersion thin film microextraction (DI-TFME) is introduced. Zein as a biodegradable, low cost and accessible polymer was used to prepare a flexible thin film with the possession of different interactions and good adsorption capacity. To improve the mechanical and chemical resistance of the film, halloysite nanotubes were combined with zein to prepare the thin film sorbent. The film was used for TFME of 16 pesticides from different chemical classes, including organochlorines and organophosphates followed by gas chromatography with electron capture detector (GC-ECD). To achieve the maximum...

Extensive Comparison between Semi-rigid Connection and Investigation of a New Semi-rigid Steel Connection

, M.Sc. Thesis Sharif University of Technology Gordan, Mahshid (Author) ; Mofid, Masoud (Supervisor)

Abstract

Steel structures are one of the most common structures in the world. One of the main parts of these structures is the connections, which are divided into three main categories of fixed, semi-rigid and joints, according to
the different criteria provided in the guidelines and codes. Perhaps the main challenge facing civil engineers has been designing efficient connections against lateral loads (seismic loads, wind loads). This issue has received more and more attention from designers due to the poor performance of the fasteners against lateral loads. Investigating and evaluating semi-rigid connections as one of the main part of steel structures against various loads, especially lateral...

Fabrication of neem tree seed shell biochar polyamide composite for determination of pesticides in environmental water samples by GC-ECD: A comparison of various hard shell nuts’ biochar in thin-film microextraction setup

, Article Journal of Food Composition and Analysis ; Volume 125 , 2024 ; 08891575 (ISSN) Keikavousi Behbahan, A ; Mahdavi, V ; Gordan, H ; Bagheri, H ; Sharif University of Technology

2024

Abstract

Pesticide detection in water is highly noted due to its effect on the whole ecosystem, which needs a preconcentration step, especially in trace levels. In this research, nut shells including almond, pistachio, walnut, hazelnut, and neem tree seed (with and without chemical modification) were pyrolyzed to prepare biochars as potential sorbents for pesticide detection in water. The extraction ability of prepared biochars was compared using a thin-film microextraction (TFME) setup with polyamide (PA) as the substrate. The role of biomass origin on the extraction efficiency was studied through the characterization process. During optimization, both weight percent of biochars in composite and...

Temperature-dependent Multi Scale Large Deformation Simulation of Heterogeneous Crystals

, M.Sc. Thesis Sharif University of Technology Gordan, Ali (Author) ; Khoei, Amir Reza (Supervisor) ; Jahanshahi, Mohsen (Co-Advisor)

Abstract

In this study, a novel and unprecedented multi-scale hierarchical molecular dynamics (MD) – finite element (FE) coupling method is proposed to demonstrate the influence of temperature on mechanical properties of heterogeneous Nano-crystalline structures. The embedded-atom method (EAM) many-body interatomic potential is implemented to consider pairwise interactions between atoms in the metallic alloys with face-centered-cubic (FCC) lattice structure at different temperatures. In addition, the Nose-Hoover thermostat is employed to adjust the fluctuation of temperature. In order to calculate the equivalent lattice parameter, a weight average between the lattice parameters of atomic structures...

A novel probabilistic simulation approach for forecasting the safety factor of slopes: a case study

, Article Engineering with Computers ; 2018 , Pages 1-10 ; 01770667 (ISSN) Mojtahedi,S. F. F ; Tabatabaee, S ; Ghoroqi, M ; Soltani Tehrani, M ; Gordan, B ; Ghoroqi, M ; Sharif University of Technology

Springer London 2018

Abstract

Stabilization of slopes is considered as the aim of the several geotechnical applications such as embankment, tunnel, highway, building and railway and dam. Therefore, evaluation and precise prediction of the factor of safety (FoS) of slopes can be useful in designing these important structures. This research is carried out to evaluate the ability of Monte Carlo (MC) technique for the forecasting the FoS of many homogenous slopes in the static condition. Moreover, the sensitivity of the FoS on the effective parameters was identified. To do this, the most important factors on FoS, such as angle of internal friction (Formula presented.), slope angle (Formula presented.) and cohesion (Formula...

A novel probabilistic simulation approach for forecasting the safety factor of slopes: a case study

, Article Engineering with Computers ; Volume 35, Issue 2 , 2019 , Pages 637-646 ; 01770667 (ISSN) Mojtahedi, S. F. F ; Tabatabaee, S ; Ghoroqi, M ; Soltani Tehrani, M ; Gordan, B ; Ghoroqi, M ; Sharif University of Technology

Springer London 2019

Abstract

Stabilization of slopes is considered as the aim of the several geotechnical applications such as embankment, tunnel, highway, building and railway and dam. Therefore, evaluation and precise prediction of the factor of safety (FoS) of slopes can be useful in designing these important structures. This research is carried out to evaluate the ability of Monte Carlo (MC) technique for the forecasting the FoS of many homogenous slopes in the static condition. Moreover, the sensitivity of the FoS on the effective parameters was identified. To do this, the most important factors on FoS, such as angle of internal friction (∅) , slope angle (α) and cohesion (C) were investigated and used as the...