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Poly(citric acid)-block-poly(ethylene glycol) copolymers-new biocompatible hybrid materials for nanomedicine
, Article Nanomedicine: Nanotechnology, Biology, and Medicine ; Volume 6, Issue 4 , Aug , 2010 , Pages 556-562 ; 15499634 (ISSN) ; Adeli, M ; Vossoughi, M ; Sharif University of Technology
2010
Abstract
Linear-dendritic ABA triblock copolymers containing poly(ethylene glycol) (PEG) as B block and hyperbranched poly(citric acid) (PCA) as A blocks were synthesized through polycondensation. The molecular self-assembly of synthesized PCA-PEG-PCA copolymers in water led to formation of nanoparticles and fibers in different sizes and shapes depending on the time and size of PCA blocks. Ten days after dissolving PCA-PEG-PCA copolymers in water, the size of fibers had reached several millimeters. Mixing a water solution of fluorescein as a small guest molecule and PCA-PEG-PCA copolymers led to the encapsulation of fluorescein by products of molecular self-assembly. To investigate their potential...
Synthesis of gold nanoparticle necklaces using linear-dendritic copolymers
, Article European Polymer Journal ; Volume 46, Issue 2 , 2010 , Pages 165-170 ; 00143057 (ISSN) ; Adeli, M ; Vossoughi, M ; Sharif University of Technology
2010
Abstract
Linear-dendritic copolymers containing hyperbranched poly(citric acid) and linear poly(ethylene glycol) blocks (PCA-PEG-PCA) were used as reducing and capping agents to synthesize and support gold nanoparticles (AuNPs). PCA-PEG-PCA copolymers with 1758, 1889 and 3446 molecular weights, called A1, A2 and A3 through this work, respectively, were synthesized using 2, 5, and 10 citric acid/PEG molar ratios. The diameter of A1, A2 and A3 in a fresh water solution was investigated using dynamic light scattering (DLS) and it was between 1.8 and 2.8 nm. AuNPs were simply synthesized and supported by addition a boiling aqueous solution of HAuCl4 to aqueous solutions of A1, A2 and A3. Supported AuNPs...
Study and Preparation of Coated Drug by PEG Biopolymer (PEGylation) for Release Controlling
, M.Sc. Thesis Sharif University of Technology ; Vossoughi, Manoochehr (Supervisor) ; Sarbolouki, Mohammad Nabi (Supervisor)
Abstract
In the first part of this work, citric acid monomer was selected to produce dendrimer through the divergent method using logical conditions (for controlling its functional groups) on the base of poly (ethylene glycol) as the core. Triblock copolymers (ABA-type) of citric acid and poly (ethylene glycol) (PCA-PEG-PCA) as biocompatible compounds were synthesized in four different molecular weights and applied as nanocarriers. The structure definition of the molecules and nanoparticles were carried out using different spectroscopy methods. Diameter of the synthesized copolymers was investigated using dynamic light scattering (DLS) experiments and transmission electron microscopy (TEM) and it was...
Organic halides and nanocone plastic structures enhance the energy conversion efficiency and self-cleaning ability of colloidal quantum dot photovoltaic devices
, Article Journal of Physical Chemistry C ; Volume 121, Issue 18 , 2017 , Pages 9757-9765 ; 19327447 (ISSN) ; Simchi, A ; Tavakoli, R ; Fan, Z ; Sharif University of Technology
American Chemical Society
2017
Abstract
This paper presents solid-state ligand exchange of spin-coated colloidal lead sulfide quantum dot (PbS QD) films by methylammonium iodide (MAI) and integration of them in depleted heterojunction solar (DHS) devices having an antireflecting (AR) nanocone plastic structure. Time-resolved photoluminescence measurements determine a shorter lifetime of the charge carries on a semiconductor (TiO2) electron transfer layer for the MAI-passivated QD films as compared with those with long-chain aliphatic or short thiol ligands. Consequently, the DHS device yields improved power conversion efficiency (>125%) relative to oleic-acid-passivated PbS QD films. Using anodized aluminum oxide templates, an...
How does psychological empowerment affect knowledge management improvement in organizations? a study of cause-and-effect relationship using the fuzzy DEMATEL method
, Article IEEE Transactions on Engineering Management ; 2021 ; 00189391 (ISSN) ; Mohammadi, M ; Maleki, A ; Bonyadi Naeini, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
The present article aims to investigate the cause-and-effect relationship between the employees’ psychological empowerment (PE) and dimensions of knowledge management (KM) in an oil company, using the fuzzy decision-making trial and evaluation laboratory method. The study population consists of oil company experts. The sample size is determined based on the theoretical saturation limit. The present findings show that PE is the strongest causative factor with significant effects on knowledge creation (KC) and knowledge dissemination (KD). Among the KM dimensions, the most influential factors are the dimensions of KC, knowledge application, and knowledge capture (KCA). Of all KM dimensions,...
Simultaneously synthesis and encapsulation of metallic nanoparticles using linear-dendritic block copolymers of poly (ethylene glycol)-poly (citric acid)
, Article Key Engineering Materials, 8 July 2010 through 9 July 2010 ; Volume 478 , July , 2011 , Pages 7-12 ; 10139826 (ISSN) ; 9783037851357 (ISBN) ; Vossoughi, M ; Adeli, M ; Sharif University of Technology
2011
Abstract
Linear-dendritic triblock copolymers of linear poly(ethylene glycol) and hyperbranched poly(citric acid) (PCA-PEG-PCA) were used as the reducing and capping agents to encapsulate gold and silver nanoparticles (AuNPs and AgNPs). PCA-PEG-PCA copolymers in four different molecular weights were synthesized using 2, 5, 10 and 20 citric acid/PEG molar ratios and were called A 1, A 2, A 3 and A 4, respectively. Nanoparticles were encapsulated simultaneously during the preparation process. AuNPs were simply synthesized and encapsulated by addition a boiling aqueous solution of HAuCl 4 to aqueous solutions of A 1, A 2, A 3 and A 4. In the case of silver, an aqueous solution of AgNO 3 was reduced...
An nnovative test bed for verification of attitude control system
, Article IEEE Aerospace and Electronic Systems Magazine ; Volume 32, Issue 6 , 2017 , Pages 16-22 ; 08858985 (ISSN) ; Faghihinia, A ; Kalhor, A ; Sharif University of Technology
2017
Abstract
A 3 DOF platform was constructed in the Georgia Institute of Technology to perform new control strategies in an experimental framework. Also in this simulator, there isn't any sensor used by a real satellite for attitude determination. The setup was structured on data transmitting and synchronization of distributed elements for ADCS tests. In such a plan, not only can different elements of the test bed be used individually, but also they can support an integrated hardware in the loop test. Accordingly, reusing the hardware sources causes a cost reduction of development. Furthermore the geometric interferences of different parts are minimized in this plan. So, the test bed can be developed...
Efficient removal of cationic dyes using a new magnetic nanocomposite based on starch-g-poly(vinylalcohol) and functionalized with sulfate groups
, Article RSC Advances ; Volume 6, Issue 44 , 2016 , Pages 38042-38051 ; 20462069 (ISSN) ; Abedin Moghanaki, A ; Tavakoli, A ; Sharif University of Technology
Royal Society of Chemistry
2016
Abstract
A magnetic nanoparticle@starch-g-poly(vinyl sulfate) nanocomposite (MNP@St-g-PVS) as a new magnetic nano-adsorbent has been prepared based on graft copolymerization of vinyl acetate onto starch in the presence of magnetic nanoparticles, where the acetate groups were converted to hydroxyl groups followed by the sulfation of the hydroxyl groups using chlorosulfonic acid. Characterization of this magnetic nanocomposite was carried out by FTIR, TGA, XRD, VSM, SEM, TEM and elemental analysis. The resulting nanocomposite was used as an adsorbent for the removal of typical cationic dyes, methylene blue (MB) and malachite green (MG), from aqueous solutions. All experimental parameters that can...
Modeling of osmotic pressure of aqueous poly(ethylene glycol) solutions using the artificial neural network and free volume flory huggins model
, Article Journal of Dispersion Science and Technology ; Volume 32, Issue 7 , 2011 , Pages 1054-1059 ; 01932691 (ISSN) ; Pazuki, G. R ; Vossoughi, M ; Alemzadeh, I ; Sharif University of Technology
2011
Abstract
In this work, the modified Flory-Huggins coupled with the free-volume concept and the artificial neural network models were used to obtain the osmotic pressure of aqueous poly(ethylene glycol) solutions. In the artificial neural network, the osmotic pressure of aqueous poly(ethylene glycol) solutions depends on temperature, molecular weight and the mole fractions of poly(ethylene glycol) in aqueous solution. The network topology is optimized and the (3-1-1) architecture is found using optimization of an objective function with batch back propagation (BBP) method for 134 experimental data points. The results obtained from the neural network in obtaining of the osmotic pressure of aqueous...
High cycle fatigue behavior and thermal properties of PLA/PCL blends produced by fused deposition modeling
, Article Journal of Polymer Research ; Volume 30, Issue 7 , 2023 ; 10229760 (ISSN) ; Sedighi, M ; Kasaeian Naeini, M ; Jabbari, A. H ; Sharif University of Technology
Springer Science and Business Media B.V
2023
Abstract
In this paper, high cycle fatigue behavior and thermal properties of blend specimens made of polylactic acid (PLA) and polycaprolactone (PCL) were studied and the influence of crystallization was investigated on the fatigue behavior. In this regard, fused deposition modeling method was employed to manufacture neat-PLA, neat-PCL, PLA/10wt.% PCL (90/10), and PLA/20wt.% PCL (80/20) specimens. The results show that the addition of 10wt.% and 20wt.% of PCL to the neat-PLA increases the elongation of the specimens by 32% and 284%, respectively, compared to that of the neat-PLA. However, Young’s modulus respectively decreases by 22% and 34%. According to the differential scanning calorimetry (DSC)...
Effect of dip-coating on tensile and high cycle fatigue behavior of 3D printed bio-polymer blends
, Article 2023 30th National and 8th International Iranian Conference on Biomedical Engineering, ICBME 2023 ; 2023 , Pages 232-236 ; 979-835035973-2 (ISBN) ; Sedighi, M ; Kasaeian Naeini, M ; Mostahsan, A. J ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2023
Abstract
Considering the desirable biodegradable properties and mechanical characteristics of poly lactic acid (PLA) and poly caprolactone (PCL), these polymers are recently widely utilized in medical applications including the fabrication of body-compatible implants. One of the most efficient manufacturing methods to fabricate polymer-based implants is 3D printing, due to its ability to rapidly produce parts with complex geometries. In this study, an effort has been made to study the impact of the dip-coating process on tensile and high cycle fatigue behavior of 3D printed PLA/PCL blends, using PCL/chloroform solution. The results demonstrate that after applying the PCL coating on the surface of the...
Policy Instruments for the Improvement of Customers’ Willingness to Purchase Electric Vehicles: A Case Study in Iran
, Article Energies ; Volume 15, Issue 12 , 2022 ; 19961073 (ISSN) ; Mirzamohammadi, S ; Naeini, A. B ; Maleki, A ; Mobayen, S ; Skruch, P ; Sharif University of Technology
MDPI
2022
Abstract
Given the various advantages of electric vehicles compared to conventional gasoline vehicles in terms of energy efficiency and environmental pollution (among others), this paper studies the factors affecting customers’ willingness to purchase electric vehicles. An integrated discrete choice and agent-based approach is applied to model the customers’ choice for the valuation of electric vehicles based on the internal reference price. The agent-based model evaluates customers’ preferences for a number of personal and vehicle attributes, according to which vehicle they chose. Data from 376 respondents are collected to estimate a random-parameter logit model where customers are asked to reveal...
Improving quality of a post's set of answers in stack overflow
, Article 46th Euromicro Conference on Software Engineering and Advanced Applications, SEAA 2020, 26 August 2020 through 28 August 2020 ; 2020 , Pages 504-512 ; Izadi, M ; Heydarnoori, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
Community Question Answering platforms such as Stack Overflow help a wide range of users solve their challenges on-line. As the popularity of these communities has grown over the years, both the number of members and posts have escalated. Also, due to the diverse backgrounds, skills, expertise, and viewpoints of users, each question may obtain more than one answer. Therefore, the focus has changed toward producing posts that have a set of answers more valuable for the community as a whole, not just one accepted-answer aimed at satisfying only the question-asker. Same as every universal community, a large number of low-quality posts on Stack Overflow require improvement. We call these posts...
Two nanostructured polymers: Polyaniline nanofibers and new linear-dendritic matrix of poly(citric acid)-block-poly(ethylene glycol) copolymers for environmental monitoring in novel biosensors
, Article International Journal of Polymeric Materials and Polymeric Biomaterials ; Volume 62, Issue 7 , Jul , 2013 , Pages 377-383 ; 00914037 (ISSN) ; Vossoughi, M ; Alemzadeh, I ; Naeini, A. T ; Darvish, M ; Sharif University of Technology
2013
Abstract
In this work two phenol biosensors, one based on polyaniline nanofibers (PNFs) and the other based on the newly created and introduced linear-dendritic matrix of poly(citric acid)-block-poly(ethylene glycol) copolymers (PCA-PEG-PCA), were chemically modified with horseradish peroxidase (HRP) enzyme. These phenol biosensors showed an oxidation peak at 0.55 V. The amperometric response for biosensors based on PNFs showed a linear response range from 2.5 × 10-6 to 2.5 × 10-5 mol/L, with a detection limit of 2.5 M phenol. Also, the amperometric response for a biosensor based on PCA-PEG-PCA showed a linear response range from 2.5 × 10-6 to 4 × 10-5 mol/L, with a detection limit of 1.5 M phenol
Investigation of the higher-order harmonics of internal vernier envelopes on the sensitivity enhancement of the integrated all-fiber cascade fabry–perot strain and temperature sensor
, Article Optical Fiber Technology ; Volume 80 , 2023 ; 10685200 (ISSN) ; Ranjbar Naeini, O. R ; Bahrampour, A. R ; Latifi, H ; Sharif University of Technology
Academic Press Inc
2023
Abstract
Fiber optic sensors have emerged as a promising technology for precise measurements in various applications. In this study, we propose an integrated all-fiber Cascade Fabry–Perot (CFP) sensor that uses the harmonic Vernier effect to enhance its sensitivity. The sensor consists of a Silica Capillary Tube (SCT) fusion spliced to a Single-Mode Fiber (SMF), and its cavity length is optimized to locate Vernier's internal envelopes for three different Vernier harmonic orders within the spectral range of 1500 nm–1600 nm. Three CFPs were fabricated and utilized as strain and temperature sensors. By analyzing and tracing Vernier's internal envelopes, we experimentally demonstrated that sensitivity...
Investigations of thermal behavior of Fe3Si2O5(OH)4·Sb3O6(OH)·Sb2O3 in air atmosphere: a study of acidic leaching process of Sb mineral
, Article Journal of Thermal Analysis and Calorimetry ; Volume 148, Issue 9 , 2023 , Pages 3295-3300 ; 13886150 (ISSN) ; Sadeghi Naeini, M ; Sharif University of Technology
Springer Science and Business Media B.V
2023
Abstract
The thermal behavior of Fe3Si2O5(OH)4·Sb3O6(OH)·Sb2O3 (a sample of antimony from Sefidabe mine in Zahedan) was investigated by the technique of thermogravimetry under air atmosphere from 25 to 1200 °C. The obtained results from TGA were reported. This study reports comprehensive information about these minerals. XRD and XRF techniques, UV/visible and elemental analysis such as ICP are used to identify the products at different decomposition steps. The acidic leaching of this mineral Fe3Si2O5(OH)4·Sb3O6(OH)·Sb2O3 is carried out, and the obtained results are reported. In total, the recovery was achieved by leaching with hydrochloric acid was 85% at D80 granulation below 45 microns. In leaching...
Study of the compaction behavior of composite powders under monotonic and cyclic loading
, Article Composites Science and Technology ; Volume 65, Issue 14 , 2005 , Pages 2094-2104 ; 02663538 (ISSN) ; Simchi, A ; Seyed Reihani, S. M ; Sharif University of Technology
2005
Abstract
The consolidation behavior of composite powders during pressure cycling at room temperature in uniaxial compaction experiments was studied and compared with monotonic compaction. Aluminum and various amounts of SiC powders (up to 50 vol%) were used to investigate the effect of hard reinforcement particle on the densification of soft aluminum matrix. The cyclic compaction was carried out at various pressure amplitudes, ranges from 90 to 360 MPa, at the frequency of 1 Hz. The pressure cycling was continued up to 5000 cycle, in which, the rate of consolidation was found to be fairly low. The consolidation of the composite powders under different loading modes was analyzed through...
Supercritical synthesis and in situ deposition of PbS nanocrystals with oleic acid passivation for quantum dot solar cells
, Article Materials Chemistry and Physics ; Volume 156 , 2015 , Pages 163-169 ; 02540584 (ISSN) ; Simchi, A ; Aashuri, H ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
Colloidal quantum dot solar cells have recently attracted significant attention due to their low-processing cost and surging photovoltaic performance. In this paper, a novel, reproducible, and simple solution-based process based on supercritical fluid toluene is presented for in situ growth and deposition PbS nanocrystals with oleic-acid passivation. A lead precursor containing sulfur was mixed with oleic acid in toluene and processed in a supercritical fluid condition at different temperatures of 140, 270 and 330 °C for 20 min. The quantum dots were deposited on a fluorine-doped tin oxide glass substrate inside the supercritical reactor. Transmission electron microscopy, X-ray diffraction,...
Surface engineering of TiO2 ETL for highly efficient and hysteresis-less planar perovskite solar cell (21.4%) with enhanced open-circuit voltage and stability
, Article Advanced Energy Materials ; Volume 8, Issue 23 , 2018 ; 16146832 (ISSN) ; Yadav, P ; Tavakoli, R ; Kong, J ; Sharif University of Technology
Wiley-VCH Verlag
2018
Abstract
Interfacial studies and band alignment engineering on the electron transport layer (ETL) play a key role for fabrication of high-performance perovskite solar cells (PSCs). Here, an amorphous layer of SnO2 (a-SnO2) between the TiO2 ETL and the perovskite absorber is inserted and the charge transport properties of the device are studied. The double-layer structure of TiO2 compact layer (c-TiO2) and a-SnO2 ETL leads to modification of interface energetics, resulting in improved charge collection and decreased carrier recombination in PSCs. The optimized device based on a-SnO2/c-TiO2 ETL shows a maximum power conversion efficiency (PCE) of 21.4% as compared to 19.33% for c-TiO2 based device....
Efficient, hysteresis-free, and flexible inverted perovskite solar cells using all-vacuum processing.Efficient, hysteresis-free, and flexible inverted perovskite solar cells using all-vacuum processing
, Article Solar RRL ; 2020 ; Yadav, P ; Prochowicz, D ; Tavakoli, R ; Sharif University of Technology
Wiley-VCH Verlag
2020
Abstract
The fabrication of efficient perovskite solar cells (PSCs) using all-vacuum processing is still challenging due to the limitations in the vacuum deposition of the hole transporting layer (HTL). Herein, inverted PSCs using copper (II) phthalocyanine (CuPC) as an ideal alternative HTL for vacuum processing are fabricated. After proper optimization, a PSC with a power conversion efficiency (PCE) of 20.3% is achieved, which is much better than the PCEs (16.8%) of devices with solution-based CuPC. As it takes a long time to dissolve CuPC in the solution-based device, the evaporation approach has better advantage in terms of fast processing. In addition, the device with the evaporated CuPC HTL...