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Design and Fabrication of a XY Nano-Positioning System
, M.Sc. Thesis Sharif University of Technology ; Nejat Pishkenari, Hossein (Supervisor)
Abstract
Nanopositioning is technology of positioning & manipulation of Nano-scale object. This technology can be considered as one of the fundamental necessities in Nano & Micro research and fabrication and made lots of unbelievable advancement in researches and technologies. There are lots of mechanical systems designed for large scale positioning with sub millimeter resolution, but when it’s come to Nano scale, the range of access should be limited to some micrometer. Also in Nano-scale motion some difficulties like backlash, stick-slip and friction is phenomenon. For increasing the workspace using coarse and fine positioning systems may be an appropriate method. In this method a fine positioning...
Design and Fabrication of a Flexure-Based Nano-Precision XY Positioning Stage
,
M.Sc. Thesis
Sharif University of Technology
;
Zohoor, Hassan
(Supervisor)
Abstract
Nanopositioning is a technology for moving a target object within nanometer (10-9 meter) resolution. Nowadays nanopositioning stages have emerged as an important technological advancement in hi-tech applications, including scanning probe microscopy, lithography, nanometrology, fabrication and assembly of nanostructures and beam steering for optical communication systems. To achieve nanometer resolution the stage must focus on a few tens of micrometers travel range. The combination of piezoelectric actuators and monolithic compliant mechanisms can provide a smooth motion without friction, wear, and backlash. So, piezo-driven compliant mechanisms are used widely in nanopositioning systems. The...
Utilizing the moiré deflectometry-based detection method improves the detection sensitivity for gold nanoparticles trapped by optical tweezers
, Article Journal of the Optical Society of America B: Optical Physics ; Volume 38, Issue 7 , 2021 , Pages 2135-2140 ; 07403224 (ISSN) ; Khorshad, A. A ; Sharif University of Technology
The Optical Society
2021
Abstract
Gold nanoparticles (GNPs) are very often used as handles for nanotechnological micromanipulation. In this regard, optical trapping of GNPs is of great importance, in which locating the trapped GNP within the focal spot with nanometer precision is crucial. Very recently, we have introduced a new position detection system for optical tweezers based on moiré deflectometry (MD). Here we show, both theoretically and experimentally, that an MD detection system could provide significantly larger detection sensitivity for a trapped GNP compared to that provided by conventional back focal plane (BFP) detection systems. For instance, for a trapped 200 nm GNP, the detection sensitivity provided by the...
Design of robust SRAM cells against single-event multiple effects for nanometer technologies
, Article IEEE Transactions on Device and Materials Reliability ; Volume 15, Issue 3 , 2015 , Pages 429-436 ; 15304388 (ISSN) ; Asgari, B ; Tabandeh, M ; Fazeli, M ; Sharif University of Technology
Abstract
As technology size scales down toward lower two-digit nanometer dimensions, sensitivity of CMOS circuits to radiation effects increases. Static random access memory cells (SRAMs) that are mostly employed as high-performance and high-density memory cells are prone to radiation-induced single-event upsets. Therefore, designing reliable SRAM cells has always been a serious challenge. In this paper, we propose two novel SRAM cells, namely, RHD11 and RHD13, that provide more attractive features than their latest proposed counterparts. Simulation results show that our proposed SRAM cells as compared with some state-of-the-art designs have considerably higher robustness against single-event...
A comparative evaluation of the additional impact of nanometer-sized tetravalent oxides on the performance of doloma-magnesia ceramic refractories
, Article Ceramics International ; Volume 44, Issue 2 , 2018 , Pages 2058-2064 ; 02728842 (ISSN) ; Gheisari Dehsheikh, H ; Karamian, E ; Nemati, A ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In this research study, a comparative evaluation of the additional impact of nanometer-sized tetravalent oxides [Zirconia (ZrO2), Titania (TiO2), and Silica (SiO2)] on the properties and performance of Doloma-Magnesia (MgO-CaO) ceramic refractories, with an emphasis on their hydration resistance improvement, has been done. For this purpose, from 0 to 2.5 wt% ZrO2, TiO2, and SiO2 nanometer-sized particles have been added to the Doloma-Magnesia compositions. After formulation and mixing of the starting materials, the pressed samples (at 150 MPa) were tempered (at 250 °C for 12 h) and fired in a shuttle furnace (at 1650 °C for 3 h). The physical, mechanical, and thermo-mechanical properties of...
Al-Al3Ti nanocomposite produced in situ by two-step hot-press sintering
, Article IOP Conference Series: Materials Science and Engineering ; Volume 40, Issue 1 , 2012 ; 17578981 (ISSN) ; Ghiabakloo, H ; Hosseini, H. R. M ; Mohammadi, A. V ; Sharif University of Technology
2012
Abstract
Aluminum reinforced with a large amount (up to about 55 vol.%) of Al 3Ti particles can be fabricated from Al-20Ti elemental nanometer-sized powder mixture via in-situ two step hot press sintering (TSS). For production of intermetallic reinforced in-situ composite, TSS can provide elevated temperature to facilitate the formation of intermetallic phase in situ and hot consolidation to form a fully dense solid. The first step sintering was employed at a higher temperature to obtain an initial high density, and the second step was held at a lower temperature by isothermal sintering for more time than the first one to increase bulk density without significant grain growth. The optimum TSS regime...
Preparation of new superhydrophobic and highly oleophobic polyurethane coating with enhanced mechanical durability
, Article Applied Surface Science ; Volume 454 , 2018 , Pages 201-209 ; 01694332 (ISSN) ; Ghadimi, M. R ; Amirpoor, S ; Dolati, A ; Sharif University of Technology
Abstract
In this study, a noble robust superhydrophobic and highly oleophobic polyurethane (PU)–SiO2 nanoparticle (NP) coating is specially designed using sol-gel process. For this purpose the effective parameters on surface tension and durability of the synthesized coating investigated and optimized. This new superhydrophobic and highly oleophobic coating exhibits good pensile hardness as high as 6H with adhesive force grade of 5B and repels water and oil with contact angles (CAs) of 159° and 140° respectively. The synthesized PU-SiO2 composite also retains an excellent amphiphobicity after a 7 days immersion in water with water and oil with CAs of 150° and 130°. Facile fabrication of PU–SiO2...
The effect of nanoparticles on spontaneous imbibition of brine into initially oil-wet sandstones
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Volume 41, Issue 22 , 2019 , Pages 2746-2756 ; 15567036 (ISSN) ; Ghasemi Dehkordi, M ; Sharif University of Technology
Taylor and Francis Inc
2019
Abstract
In this paper, the effect of silica nanoparticles on oil production due to the spontaneous imbibition of brine into oil-wet sandstones has been studied. The imbibed fluids were NaCl 3 wt. % solutions containing various concentrations of nanoparticles and the recovered oil for each solution was compared. The results revealed that nanoparticles yielded more oil recovery. Nanofluid was used after brine imbibition, and the oil recovery increased from 17.8% to 40% while in the case of using the same nanofluid as the first imbibed fluid the oil recovery was 53%. Also, the results indicated that the oil recovery depends on nanoparticle concentrations. © 2019, © 2019 Taylor & Francis Group, LLC
Enhanced local viscosity around colloidal nanoparticles probed by equilibrium molecular dynamics simulations
, Article Journal of Chemical Physics ; Volume 155, Issue 17 , 2021 ; 00219606 (ISSN) ; Saidi, M. H ; Joly, L ; Merabia, S ; Rajabpour, A ; Sharif University of Technology
American Institute of Physics Inc
2021
Abstract
Nanofluids - dispersions of nanometer-sized particles in a liquid medium - have been proposed for a wide variety of thermal management applications. It is known that a solid-like nanolayer of liquid of typical thicknesses of 0.5-1 nm surrounding the colloidal nanoparticles can act as a thermal bridge between the nanoparticle and the bulk liquid. Yet, its effect on the nanofluid viscosity has not been elucidated so far. In this article, we compute the local viscosity of the nanolayer using equilibrium molecular dynamics based on the Green-Kubo formula. We first assess the validity of the method to predict the viscosity locally. We apply this methodology to the calculation of the local...
Room-temperature quantum effect in silicon nanoparticles obtained by low-energy ion implantation and embedded in a nanometer scale capacitor
, Article Applied Physics Letters ; Volume 86, Issue 16 , 2005 , Pages 1-3 ; 00036951 (ISSN) ; Grisolia, J ; Assayag, G. B ; Coffin, H ; Atarodi, S. M ; Claverie, A ; Sharif University of Technology
2005
Abstract
In this article, we present the room-temperature current-voltage characteristics of a nanometer scale (100×100 nm2) metal-oxide-semiconductor capacitor containing few (less than 100) silicon nanoparticles. The layer of silicon nanoparticles is synthesized within the oxide of this capacitor by ultra low-energy ion implantation and annealing. Current fluctuations in the form of discrete current steps and sharp peaks appeared in the static and dynamic I (V) characteristics of the capacitor. These features have been associated to quantized charging and discharging of the nanoparticles and the resulting Coulomb interaction to the tunneling current. © 2005 American Institute of Physics
Optimal sliding mode control of AFM tip vibration and position during manipulation of a nanoparticle
, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings ; Vol. 12, Issue. PART A , 2010 , pp. 205-214 ; ISBN: 9780791843857 ; Khorsand, M ; Meghdari, A ; Alasty, A ; Sharif University of Technology
Abstract
This research regards to a two-dimensional lateral pushing nanomanipulation using Atomic Force Microscope (AFM). Yet a reliable control of the AFM tip position during the AFM-based manipulation process is a chief issue since the tip can jump over the target nanoparticle and then the process can fail. However, a detailed Modeling and understanding of the interaction forces on the AFM tip is important for prosperous manipulation control and a nanometer resolution tip positioning. In the proposed model, Lund-Grenoble (LuGre) dynamic friction model is used as friction force on the contact surface between the nanoparticle and the substrate. This model leads to a stick-slip behavior of the...
Data center power reduction by heuristic variation-aware server placement and chassis consolidation
, Article CADS 2012 - 16th CSI International Symposium on Computer Architecture and Digital Systems ; 2012 , Pages 150-155 ; 9781467314824 (ISBN) ; Momtazpour, M ; Goudarzi, M ; Sharif University of Technology
2012
Abstract
The growth in number of data centers and its power consumption costs in recent years, along with ever increasing process variation in nanometer technologies emphasizes the need to incorporate variation-aware power reduction strategies in early design stages. Moreover, since the power characteristics of identically manufactured servers vary in the presence of process variation, their position in the data center should be optimally determined. In this paper, we introduce two heuristic variation-aware server placement algorithm based on power characteristic of servers and heat recirculation model of data center. In the next step, we utilize an Integer Linear Programming (ILP) based...
Experimental investigation of forced convective heat transfer coefficient in nanofluids of Al2O3/EG and CuO/EG in a double pipe and plate heat exchangers under turbulent flow
, Article Experimental Thermal and Fluid Science ; Volume 35, Issue 3 , April , 2011 , Pages 495-502 ; 08941777 (ISSN) ; Oskouie, S. N ; Doosthoseini, A ; Joneidi, A ; Pazouki, M ; Sharif University of Technology
2011
Abstract
Nanofluid is the term applied to a suspension of solid, nanometer-sized particles in conventional fluids; the most prominent features of such fluids include enhanced heat characteristics, such as convective heat transfer coefficient, in comparison to the base fluid without considerable alterations in physical and chemical properties. In this study, nanofluids of aluminum oxide and copper oxide were prepared in ethylene glycol separately. The effect of forced convective heat transfer coefficient in turbulent flow was calculated using a double pipe and plate heat exchangers. Furthermore, we calculated the forced convective heat transfer coefficient of the nanofluids using theoretical...
Optimal sliding mode control of AFM tip vibration and position during manipulation of a nanoparticle
, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings, 13 November 2009 through 19 November 2009, Lake Buena Vista, FL ; Volume 12, Issue PART A , 2010 , Pages 205-214 ; 9780791843857 (ISBN) ; Khorsand, M ; Meghdari, A ; Alasty, A ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2010
Abstract
This research regards to a two-dimensional lateral pushing nanomanipulation using Atomic Force Microscope (AFM). Yet a reliable control of the AFM tip position during the AFM-based manipulation process is a chief issue since the tip can jump over the target nanoparticle and then the process can fail. However, a detailed Modeling and understanding of the interaction forces on the AFM tip is important for prosperous manipulation control and a nanometer resolution tip positioning. In the proposed model, Lund-Grenoble (LuGre) dynamic friction model is used as friction force on the contact surface between the nanoparticle and the substrate. This model leads to a stick-slip behavior of the...
The effect of pH and ionic strength on the transport of alumina nanofluids in water-saturated porous media: Experimental and modeling study
, Article Journal of Thermal Analysis and Calorimetry ; Volume 137, Issue 4 , 2019 , Pages 1169-1179 ; 13886150 (ISSN) ; Yoozbashizadeh, H ; Madaah Hosseini, H. R ; Sharif University of Technology
Springer Netherlands
2019
Abstract
Alumina nanofluids are one of the most useful nanofluids, especially for increasing the thermal conductivity. Due to importance of porous media in the improvement of heat transfer, this study investigates the transport and retention of gamma alumina/water nanofluid in the water-saturated porous media. For this purpose, alumina nanofluids were introduced to the porous media consisting of water-saturated glass beads possessing various pH values (4, 7 and 10) and different ionic strengths (0.001 M of KCl, CaCl2, AlCl3, K2SO4, CaSO4, Al2(SO4)3, K2CO3 and CaCO3). Then the break through curve of each experiment was drawn and modeled by combining classical filtration theory with...
Hexagonal core–shell SiO2[–MOYI]Cl–]Ag nanoframeworks for efficient photodegradation of the environmental pollutants and pathogenic bacteria
, Article Journal of Inorganic and Organometallic Polymers and Materials ; Volume 29, Issue 4 , 2019 , Pages 1314-1323 ; 15741443 (ISSN) ; Asgarpour, F ; Akbari, A ; Eftekhari Sis, B ; Lammel, G ; Sharif University of Technology
Springer New York LLC
2019
Abstract
Hexagonal core–shell SiO2[–MOYI]Cl–]Ag nanoframeworks were synthesized via surface modification of hexagonal silica nanoparticles prepared from perlite (EP) as a cheap and abundant raw material. The prepared samples were well characterized by X-ray diffraction powder (XRD), energy dispersive X-ray (EDX), diffuse reflectance spectroscopy (DRS), Brunauer–Emmett–Teller (BET) specific surface area analysis, fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The XRD patterns confirmed that Ag and AgCl crystalline phases were successfully loaded on the surface. The TEM images were also implied that the...
Photocatalytic and photoluminescence properties of ZnO/graphene quasi core-shell nanoparticles
, Article Ceramics International ; Volume 45, Issue 7 , 2019 , Pages 8945-8961 ; 02728842 (ISSN) ; Nemati, A ; Simchi, R ; Choong Un, C ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In this paper, a combination of in-situ chemical synthesis and electrolysis methods was applied for the preparation of zinc oxide/graphene oxide quasi core-shell nanoparticles. Pure zinc oxide was also prepared using the same method at different temperatures. 100 °C was selected for synthesizing the ZnO/GO quasi core-shell (zinc oxide as a core and few layers of graphene oxide as a shell). The particle size was 15 ± 2 nm in all samples. In both processes, oxygen was the main reason for the connection between the core and the shell. XRD patterns also confirmed the formation of ZnO (with regular wurtzite structure) and ZnO/GO quasi core-shell structures. Raman spectroscopy results confirmed...
Effect of interphase zone on the overall elastic properties of nanoparticle-reinforced polymer nanocomposites
, Article Journal of Composite Materials ; Volume 53, Issue 9 , 2019 , Pages 1261-1274 ; 00219983 (ISSN) ; Jam, J. E ; Arab, B ; Firouz Abadi, R. D ; Sharif University of Technology
SAGE Publications Ltd
2019
Abstract
In the current work, the effect of interphase region on the mechanical properties of polymer nanocomposites reinforced with nanoparticles is studied. For this purpose, a closed-form interphase model as a function of radial distance based on finite-size representative volume element is suggested to estimate the mechanical properties of particle-reinforced nanocomposites. The effective Young’s and shear moduli of thermoplastic polycarbonate-based nanocomposites for a wide range of sizes and volume fractions of silicon carbide nanoparticles are investigated using the proposed interphase model and molecular dynamics simulations. In order to investigate the effect of particle size, several unit...
Developing a new superhydrophilic and superoleophobic poly(4-(1-vinyl-1H-imidazol-3-ium-3-yl) butane-1-sulfonate): vinyl imidazole@Perfluorooctanoic acid@SiO2 coated stainless steel mesh for highly efficient, stable, and durable oil/water separation
, Article Journal of Coatings Technology and Research ; 2020 ; Siavash Moakhar, R ; Amirpoor, S ; Azad, M ; Dolati, A ; Sharif University of Technology
Springer
2020
Abstract
The design and development of efficient approaches for water–oil separation have had widespread interest. Most previously introduced techniques and materials used for development of the successful separation of oily wastewater could not answer all the desired demands, such as being efficient and environmentally and economically friendly. Therefore, in seeking a novel method capable of answering these expectations, surfaces with special wettability were introduced. A novel, reusable, and recyclable superhydrophilic and superoleophobic poly(Vsim-Vim)@PFOA@SiO2 nanocomposite-coated stainless steel mesh was synthesized through a facile preparation process. Since the most important factors of...
Developing a new superhydrophilic and superoleophobic poly(4-(1-vinyl-1H-imidazol-3-ium-3-yl) butane-1-sulfonate): vinyl imidazole@Perfluorooctanoic acid@SiO2 coated stainless steel mesh for highly efficient, stable, and durable oil/water separation
, Article Journal of Coatings Technology and Research ; Volume 18, Issue 2 , 2021 , Pages 511-521 ; 15470091 (ISSN) ; Siavash Moakhar, R ; Amirpoor, S ; Azad, M ; Dolati, A ; Sharif University of Technology
Springer
2021
Abstract
The design and development of efficient approaches for water–oil separation have had widespread interest. Most previously introduced techniques and materials used for development of the successful separation of oily wastewater could not answer all the desired demands, such as being efficient and environmentally and economically friendly. Therefore, in seeking a novel method capable of answering these expectations, surfaces with special wettability were introduced. A novel, reusable, and recyclable superhydrophilic and superoleophobic poly(Vsim-Vim)@PFOA@SiO2 nanocomposite-coated stainless steel mesh was synthesized through a facile preparation process. Since the most important factors of...