Sharif Digital Repository

In this research "MnO2/MWCNT" nanocomposite was prepared firstly and then it was used as an adsorbent for Cr+3 ions removal from aqueous solutions. Our results showed that the prepared nanocomposite from modified multi-wall carbon nanotube and MnO2 has a good capacity for Cr+3 removal from aqueous solution. Morphology and Crystallinity of the modified MWCNT before and after deposition on MnO2 were examined by SEM and XRD. In turn, the experimental results were examined according to the Langmuir, Freundlich and Temkin Isotherms and Freundlich isotherm represented our experimental results  

In this research "MnO2/MWCNT" nanocomposite was prepared firstly and then it was used as an adsorbent for Cr+3 ions removal from aqueous solutions. Our results showed that the prepared nanocomposite from modified multi-wall carbon nanotube and MnO2 has a good capacity for Cr+3 removal from aqueous solution. Morphology and Crystallinity of the modified MWCNT before and after deposition on MnO2 were examined by SEM and XRD. In turn, the experimental results were examined according to the Langmuir, Freundlich and Temkin Isotherms and Freundlich isotherm represented our experimental results  

In this study, nano-sized diamond particles (ND) were functionalized in two consecutive stages. First, dry thermal oxidation was employed to obtain carboxylated ND. In the next step, carboxylated ND was properly surface modified through wet chemistry to acquire aminated-ND (ND-NH2). Then, polyaniline (PANI) was synthesized in the presence of aminated-ND particles at a broad concentration from 1 wt% to 70 wt% to obtain PANI/ND hybrid nanostructures. The chemical structure, morphology, and thermal stability of nanoparticles were comprehensively characterized by different techniques such as FT-IR, UV–visible, TGA, XRD, FESEM, and TEM. It was observed that the morphology of PANI/ND... 

Deep neural networks are currently the best solution for road and traffic scene interpretation for autonomous and self-driving vehicles. Compared to the autonomous cars, motorcycles have significant flexibility and advantages in crowded traffic situations and especially in non-urban and off-road areas. Many off-road tracks especially for agriculture and environment management tasks are only traversable with motorcycles. In this paper, a deep neural network is used for design and implementation of the vision system for navigation of an autonomous motorcycle. The proposed framework is evaluated using real world scenarios captured by a real motorcycle in various complex situations. The... 

A novel high-throughput device based on 96-micro-solid phase extraction (96-μ-SPE) system was constructed for multiresidue determination of nine pesticides in aquatic samples. The extraction procedure was performed on a commercially available 96-well plate system. The extraction module consisted of 96 pieces of 1cm×3cm of cylindrically shaped stainless steel meshes. The prepared meshes were fixed in a home-made polytetrafluoroethylene-based constructed ninety-six holes block for possible simultaneous immersion of meshes into the center of individual wells. Dodecyl methacrylate and ethylene glycol dimethacrylate was copolymerized as a monolithic polymer and placed in the cylindrically shaped... 

In this research study, interfacial assembled nanoporous zeolitic imidazolate framework (ZIF-8) multiwalled oxidized carbon nanotubes (MW-OCNTs) were developed and introduced into a silane coating. To analyze the destructive behavior of the nanoparticles exposed to salty solutions with three distinctive pHs of 2, 7.5, and 12, various types of tests such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and inductively coupled plasma (ICP) were accomplished. The XRD test revealed that the main characteristic peaks of ZIF-8 were eliminated and/or their intensity decreased. In accordance with the obtained data from the XRD test, nanoparticles at pH = 2 had been... 

Designing a novel epoxy composite system with dual self-healing/barrier anti-corrosion functions using graphene oxide (GO) nano-platforms decorated by polypyrrole (PPy) nanoparticles doped with zinc metal ions is the major objective of this research attempt. GO-PPy-Zn nanoplatform was fabricated via one-pot polymerization of pyrrole monomers on GO and two direct/indirect methods of zinc doping. In order to verify the PPy nanoparticles synthesis on GO sheets several analyses such as UV–visible, XPS, HR-TEM and FE-SEM were performed. The epoxy nanocomposite coatings containing GO-PPy and GO-PPy-Zn nanoplatforms were fabricated and applied on carbon steel. The nanocomposite coatings... 

In this study, the Peganum harmala seed extract (PHSE) was used as a green reducing agent of graphene oxide with high deoxygenation capability. PHSE not only acts as a reducing agent of GO due to the high amount of nitrogen-rich compounds but also plays an essential role in the particles' active anti-corrosion performance improvement. In order to add more active inhibition property, the zinc cations were doped successfully on the chemical structure of GO nanosheets, and eventually, the RGO-PHSE-Zn nanocomposite was obtained. The FT-IR results and UV–visible achievements declared that the epoxide (-C-O-C-) functional groups attached to the surface of the GO nanosheets had been successfully... 

Commercial paints and coatings can serve as a protective barrier for metallic substrates in a corrosive environment. A considerable variety of nanostructures can be embedded in a polymeric coating to achieve both barrier and active protection. This research aims to elucidate the role of polyaniline (PANI) as an active polyelectrolyte modifier for the surface modification of mesoporous silica nanoparticles (MSNs) doped with zinc cations (Zn2+). To characterize the samples, we employed different techniques, including field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), N2 adsorption-desorption, Fourier transform infrared spectroscopy (FTIR), Raman... 

In this paper the classical molecular structural mechanics model of graphene is modified to improve its accuracy for the analysis of transverse deformations. To this aim, a sample graphene sheet under a uniform pressure is modeled by both molecular dynamics and molecular structural mechanics methods. The sectional properties of the beam element, by which the covalent bonds are modeled, are modified such that the difference between the results of the molecular mechanics model and molecular dynamics simulation is minimized. Using this modified model, the buckling behavior of graphene under a uniform edge pressure is investigated subjected to different boundary conditions for both zigzag and... 

In this paper, a hierarchical predictive controller is designed in order to solve the tracking problem of a moving ground target by a quad-rotor in an unknown and uneven environment. This controller has internal and external predictive controller levels. In the lower layer of the controller, a constrained predictive controller is designed that is capable of rejecting perturbations and quickly tracking the reference path, and in the outer loop, a model predictive controller is designed to optimally detect the moving ground target where, the sub-cost functions were defined so that the quad-rotor would be able to track the moving ground target even if it was temporarily out of sight of the... 

In this paper, a hierarchical predictive controller is designed in order to solve the tracking problem of a moving ground target by a quad-rotor in an unknown and uneven environment. This controller has internal and external predictive controller levels. In the lower layer of the controller, a constrained predictive controller is designed that is capable of rejecting perturbations and quickly tracking the reference path, and in the outer loop, a model predictive controller is designed to optimally detect the moving ground target where, the sub-cost functions were defined so that the quad-rotor would be able to track the moving ground target even if it was temporarily out of sight of the... 

In this article, an integrated guidance and control design method for general nonlinear flexible hypersonic flight vehicles in the presence of dynamic uncertainties based on the (Formula presented.) adaptive state feedback control approach is presented. Initially, the 6-degree-of-freedom integrated guidance and autopilot dynamic model is organized using the combination of flexible uncertain hypersonic flight vehicle dynamic model and hypersonic flight vehicle-target relative motion model whereas aerodynamic and model uncertainties, cross-coupling effects, and disturbances are considered. The proposed integrated guidance and control method based on (Formula presented.) adaptive control scheme... 

In this paper, we study theoretically the generation of high repetition rate short pulses using fiber optical parametric amplification. We show that the pulse shape and duration depend on the signal location relatively to the pump frequency. We demonstrate that in order to get the shortest pulse width, the signal must be located at one of the extremities of the gain spectrum associated with the pump peak power. We derive the analytical expression of the pulse shape in this case and compare it to the exponential gain regime case. Using numerical simulations, we also analyze the impact of walk-off and pump phase modulation that is required to suppress Stimulated Brillouin Scattering and derive... 

This paper reports a polarization controllable and angle-insensitive perfect metamaterial absorber (PMA). The proposed PMA consists of periodically arranged asymmetric omega-shaped resonators made of metallic copper. The absorptivity was analyzed considering the microwave C-band from 4 GHz to 8 GHz. The proposed PMA shows an absorption peak with almost 100% absorptivity at 6.2 GHz. Also, wideband negative index of refraction is observed. Further, the absorber is inspected for the different rotation angles of the top metasurface (omega-shaped ring) along the optical axis, and obliquity of incidence angle for both TE and TM polarized waves. Moreover, surface electric field and surface current... 

In cloud computing, services play key roles. Services are well defined and autonomous components. Nowadays, the demand of using Fuzzy inference as a service is increasing in the domain of complex and critical systems. In such systems, along with the development of the software, the cost of detecting and fixing software defects increases. Therefore, using formal methods, which provide clear, concise, and mathematical interpretation of the system, is crucial for the design of these Fuzzy systems. To obtain this goal, we introduce the Fuzzy Inference Cloud Service (FICS) and propose a novel discipline for formal modeling of the FICS. The FICS provides the service of Fuzzy inference to the... 

The mixed nano-ferrites materials Cu0.6Zn0.4HoxFe2−xO4 (0.00 ≤ x ≤ 0.12) were prepared via the sol–gel auto combustion technique. The TGA curve established the annealing temperature (500 °C) for phase formation. The single exothermic peak on the DSC plot occurred at 341 °C temperature. XRD patterns of these nano ferrites verified single phase formation of the FCC cubic structure. The lattice constant a was increased from 8.4244 to 8.4419 Å and then its value decreased to 8.4319 Å. Crystallite size was found in the range of 7 to 16 nm. The surface morphology of the samples was observed from the scanning electron microscope (SEM) images. The grain size was found within the range of 90 nm to...