ORIGINAL_ARTICLE
On the oscillatory frequency of the carbon nanotube-based nanothermometers
Electromechanical nanothermometers are instruments that work on the basis of the van der Waals (vdW) potential energy and interaction force of their constituent carbon nanotubes (CNTs). The CNT-based nanothermometers have two different congurations: telescope and shuttle congurations. In this article, based on the Lennard-Jones potential function together with the continuum approximation, first, the vdW potential energy and interaction force for a telescope conguration with nite CNTs are derived, which have not been obtained in the previous research studies. Thereafter, by employing the interaction force, the equation of motion between constituent CNTs is solved. Subsequently, a new semi-analytical expression is obtained which enables one to precisely evaluate the oscillation frequency. By employing the given formulae, effects ofdierent system parameters on the vdW interactions and oscillation frequency are shown.
https://scientiairanica.sharif.edu/article_4139_9698ec79273993c1fa416aa9c152ff4d.pdf
2017-06-01
1615
1625
10.24200/sci.2017.4139
Electromechanical nanothermometers
carbon nanotubes
Continuum approximation
Oscillation frequency
R.
Ansari
1
Department of Mechanical Engineering, University of Guilan, Rasht, P.O. Box 3756, Iran
LEAD_AUTHOR
M.
Daliri
2
Department of Mechanical Engineering, University of Guilan, Rasht, P.O. Box 3756, Iran
AUTHOR
M.
Hosseinzadeh
3
Department of Mechanical Engineering, University of Guilan, Rasht, P.O. Box 3756, Iran.
LEAD_AUTHOR
ORIGINAL_ARTICLE
Retracted: Thermally-aware circuit modeling and performance analysis of single-walled carbon nanotube bundle as VLSI interconnects
Temperature-dependent delay, power dissipation, and Power Delay Product (PDP) are analyzed in a single-walled carbon nanotube (SWCNT) bundle interconnect. Thermally-aware circuit model for a metallic SWCNT bundle is presented. The results are compared with those of the currently used copper interconnects at 22 nm technology node. It is seen that delay, power dissipation, and PDP of SWCNT bundle interconnect increase with a rise in temperature from 300 K to 450 K at dierent interconnect lengths from 100 m to 1000 m. It is also observed that with rise in temperature, SWCNT bundle has a lower delay than that of copper for all interconnect lengths, whereas the reverse is true for power dissipation. In addition, with rise in temperature from 300 K to 450 K, for interconnect lengths at 100 m and 400 m, SWCNT bundle has lower PDP compared to copper interconnects, whereas the reverse is true for interconnect lengths at 700 m and 1000 m. Moreover, relative average improvement in delay, power, and PDP using thermally-aware resistance model is estimated in comparison with temperatureindependent resistance model of an SWCNT bundle. Based on simulation results, the thermally-aware resistance model of a SWCNT bundle achieved improvement in accuracyof delay, power, and PDP estimation of about 22.44%, 7.59%, and 31.96%, respectively, on average.
https://scientiairanica.sharif.edu/article_4140_d41d8cd98f00b204e9800998ecf8427e.pdf
2017-06-01
1626
1634
10.24200/sci.2017.4140
Carbon nanotube (CNT)
Interconnects
Single walled carbon nanotube (SWCNT)
Delay analysis
Power dissipation
Power Delay Product (PDP)
ORIGINAL_ARTICLE
An analytical solution for bending, buckling, and free vibration of FG nanobeam lying on Winkler-Pasternak elastic foundation using different nonlocal higher order shear deformation beam theories
In the present study, various Higher-order Shear Deformation beam Theories (HSDTs) are applied in order to achieve the exact analytical solution to bending, buckling, and free vibration of Functionally Graded (FG) nanobeam lying on the Winkler and Pasternak elastic foundations. HSDTs are those in which the effect of transverse shear strain is included. The displacement field of these theories involves a quadratic variationof transverse shear strains and stresses; hence, this hypothesis leads to the diminishing of transverse shear stresses at the top and bottom surfaces of a beam. Thus, necessarily, there is no need to use a shear correction factor in the HSDTs. Nanobeam has been made of FG materials in which the properties of these materials are changed through the thickness direction of nanobeam according to the power-law distribution. Hamilton's principle is used to derive the equation of motions and the related boundary conditions of simplysupported nanobeam. The present study shows that the stability and vibration behaviors of FG nanobeam are extremely dependent on the Winkler and Pasternak elastic foundation, gradient index, aspect ratio, and nonlocal parameter. The obtained results of the present study might be useful in the advanced field of micro/nano electromechanical systems.
https://scientiairanica.sharif.edu/article_4141_b8db5364ea91c666d2bf8ba2e685f6b3.pdf
2017-06-01
1635
1653
10.24200/sci.2017.4141
Winkler-Pasternak elastic foundation
Nonlocal Higher order Shear Deformation Theories (HSDTs)
Functionally Graded (FG) nanobeam
Bending
buckling
free vibration
V.
Refaeinejad
1
Smart Structures and New Advanced Materials Laboratory, Department of Mechanical Engineering, University of Zanjan, Zanjan, Iran.
AUTHOR
O.
Rahmani
istmcjlu@scientiaunknown.non
2
Smart Structures and New Advanced Materials Laboratory, Department of Mechanical Engineering, University of Zanjan, Zanjan, Iran.
LEAD_AUTHOR
S.A.H.
Hosseini
3
Smart Structures and New Advanced Materials Laboratory, Department of Mechanical Engineering, University of Zanjan, Zanjan, Iran
AUTHOR
ORIGINAL_ARTICLE
Evaluation of physical and mechanical properties of B-tri-calcium phosphate/poly-3-hydroxybutyrate nanocomposite scaffold for bone tissue engineering application
One of the major challenges facing researchers of tissue engineering is the scaold design with desirable physical and mechanical properties for growth and proliferation of cells and tissue formation. In this paper, rstly, -tricalcium phosphate (-TCP) nanopowders with particle size of 50-70 nm were synthesized using a simple sol-gel route with calcium nitrate and potassium dihydrogenphosphate as calcium and phosphorusprecursors, respectively. Then, the porous ceramic scaold containing 40, 50, and 60 wt% of n-TCP was prepared by the polyurethane sponge replication method. The scaffolds were coated with P3HB for 30 sec and 1 min in order to increase the scaold's mechanical properties. XRD, XRF, SEM, TEM, and FT-IR were used in order to study the phase and element structure, morphology, particle size, and determination of functional groups respectively. Based on the results of compressive strength and porosimetry tests, the most appropriate type of scaold is 50 wt% of n-TCP immersed for 30 sec in P3HB with 75% porosity in 200-600 m, with a compressive strength of 1.09 MPa and a compressive modulus of 33 MPa, which can be utilized in bone tissue engineering.
https://scientiairanica.sharif.edu/article_4142_06671d7f7c6dd6c04beabbce8c699f30.pdf
2017-06-01
1654
1668
10.24200/sci.2017.4142
Nano-B-tricalcium phosphate (B-TCP)
Poly-3- hydroxybutyrate (P3HB)
Scaffold
Tissue Engineering
Sh.
Shahi
1
Department of Material Engineering, Shahreza Branch, Islamic Azad University, Shahreza, Isfahan, Iran
AUTHOR
S.
Karbasi
2
Biomaterials Group, Advance Medical Technology Department, Isfahan University of Medical Sciences, Isfahan, Iran
LEAD_AUTHOR
ORIGINAL_ARTICLE
Petahertz-frequency plasmons in graphene nanopore and their application to nanoparticle sensing
The Surface Plasmon Resonance (SPR) properties in the petahertz (1015 Hz) frequency range for monolayer graphene nanosheet and graphene nanopore are investigated using discrete dipole approximation method. We calculate graphene refractive indices by using rst-principle density functional theory. The near-field enhancement made by plasmon in these structures is studied by employing nite-dierence-time-domain method. For graphene nanosheets, energy of the SPR peak drops with increase in the sheet length. Also, for graphene nanopores smaller than 5 nm in length, increasing the pore diameter decreases energy of the SPR peak and for some length values like 6 nm, this energy value is raised. For larger sheets (e.g., 8 nm), SPR peak is rather unchanged by variations of the pore diameter. The SPR is used to detect nanoscale objects such as gold, silver, copper, rhodium, and aluminium oxide. If nanoscale particles are inserted into the graphene nanopore, 0.195 to 0.474 eV shift in the SPR spectra appears. Type of the presented nanoparticle can be clearly determined by measuring the energy shifts in the SPR spectra. Our results show that petahertz-frequency plasmon in graphene nanopore can be used as a nanoscale-object detection methodology.
https://scientiairanica.sharif.edu/article_4143_289fd8fbb52e203abcc17e9cbe553bb6.pdf
2017-06-01
1669
1677
10.24200/sci.2017.4143
Interband plasmon
graphene
nanopore
Nanoparticle
Discrete Dipole Approximation (DDA)
B.
Fotouhi
1
Department of Electrical & Computer Engineering, Tarbiat Modares University, Tehran, Iran.
AUTHOR
V.
Ahmadi
2
Department of Electrical & Computer Engineering, Tarbiat Modares University, Tehran, Iran.
LEAD_AUTHOR
M.
Abasifard
3
Department of Electrical & Computer Engineering, Tarbiat Modares University, Tehran, Iran
AUTHOR
V.
Faramarzi
4
Department of Electrical & Computer Engineering, Tarbiat Modares University, Tehran, Iran.
AUTHOR
ORIGINAL_ARTICLE
Enhanced electro-oxidation of urea based on nickel nanoparticle decorated reduced graphene oxide/PEDOT:PSS composite
A facile two-step systematic plan of action was used to prepare nanocomposite of Reduced Graphene Oxide (RGO) doped poly(3,4-ethylenedioxythiophene):poly (styrene sulfonate) (PEDOT:PSS) decorated with nickel nanoparticles (Ni NPs) onto a Glassy Carbon Electrode (GCE). Composites of PEDOT:PSS and RGO were prepared by mixing each component solution and were fabricated as a benecial substrate for Ni NPs. Ni NPs were electrodeposited on the PEDOT-RGO support by applying constant potential into nickel ions solutions. Then, Ni/PEDOT-RGO/GCE was employed as an efficient electrocatalyst for electrooxidation of urea. The electrocatalytic properties of Ni NPs/PEDOT-RGO modied glassy carbon electrode toward the oxidation of ureawere analyzed by Cyclic Voltammetry (CV) and chronoamperometry (CA). Such studies evidenced the high electrocatalytic activity of Ni NPs and mixed PEDOT-RGO, which is mainly ascribed to the good electrochemical activity of PEDOT-RGO composites and the well-dispersed Ni NPs on the surface of PEDOT-RGO composite.
https://scientiairanica.sharif.edu/article_4144_3c9f0f9563e9f57accf9cd9b39aed0f2.pdf
2017-06-01
1678
1685
10.24200/sci.2017.4144
Poly(3,4- ethylenedioxythiophene)
reduced graphene oxide
Nickel nanoparticles
Electro-oxidation
urea
M.
Mazloum-Ardakani
1
Department of Chemistry, Faculty of Science, Yazd University, Yazd, P.O. Box 89195-741, Iran.
LEAD_AUTHOR
F.
Farbod
2
Department of Chemistry, Faculty of Science, Yazd University, Yazd, P.O. Box 89195-741, Iran
AUTHOR
L.
Hosseinzadeh
3
Department of Chemistry, Faculty of Science, Yazd University, Yazd, P.O. Box 89195-741, Iran
AUTHOR
ORIGINAL_ARTICLE
Natural convection and entropy generation of ultrafine atmospheric aerosols in the presence of hydrodynamic partial slip and thermal radiation due to solar energy
Combined eects of hydrodynamic partial slip, thermal radiation due to solar energy, and nanoparticles volume fraction on natural convection and entropy generation of atmospheric ultrane aerosols sample enclosed within a two-sided lid-driven cavity are studied numerically in the present contribution. Partial slip eect is taken intoaccount along the two horizontal moving walls, and thermal radiation is considered through Rosseland approximation. The governing equations are solved using an accurate finite volume method based on SIMPLE algorithm. The impact of Brownian motion of nanoparticles is also considered in this study, whereby KKL (Koo-Kleinstreuer-Li) correlation is utilized for simulating the eective thermal conductivity and viscosity of nanouid. The heatline visualization technique is also utilized to study the energy flux within the cavity. A comprehensive study is conducted on the controlling parameters, including partial slip coecient ( = 0 5), radiation parameter (Rd = 0 2), and nanoparticles volume fraction ( = 0 4%), which influence the ow and heat transfer characteristics. Results show that the partial slip usually eliminates the effect of mechanical forces provoked by the moving lids. Moreover, thermal radiation homogenizes the mediumthermally, which results in decreasing the average entropy generation. It is also observed that the eect of carbon-black nanoparticles on the atmospheric heat transfer manifests a wide variety of fashions mainly dependent on the presence or absence of thermal radiation due to solar energy.
https://scientiairanica.sharif.edu/article_4145_17b18ba5209da4c182a3ea1c644028ed.pdf
2017-06-01
1686
1705
10.24200/sci.2017.4145
Aerosol particles
Natural convection of nano fluids
Partial slip
thermal radiation
Heatline visualization
entropy generation
O.
Ghaffarpasand
1
Department of Physics, University of Isfahan, Isfahan 81746, Iran
LEAD_AUTHOR
ORIGINAL_ARTICLE
Copper-doped and copper-free bioactive glass nanopowders cytotoxicity and antibacterial activity assessment
The purpose of this study is to evaluate the antibacterial activity and cytotoxicity of copper-doped (Cu45SBG) and copper-free bioactive glass (45SBG) nanopowders. The antibacterial eect was studied using Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria. The BG nanopowders were synthesized by the sol-geltechnique. They were characterized by various techniques and their cytotoxicity was evaluated by MTT assay. Chemical compositions of BGs were as the same as the predicted compositions. The size of the BGs with an amorphous structure was measured to be around 100 nm. Both BG nanopowders have no antibacterial eect on broth concentrations less than 12.5 mg/ml. They demonstrated similar antibacterial activity on E. coli withMinimum Bactericidal Concentration (MBC) of 12.5 mg/ml. Cu45SBG nanopowders with the MBC of 25 mg/ml were more ecient on S. aureous bacteria than 45SBG nanopowders with the MBC of 50 mg/ml. Compared to 45SBG, Cu45SBG showed much more cytotoxicity. 45SBG demonstrated similar cells viability to the control. It was concluded that to overcome cytotoxic eect, Cu content of BGs nanopowders must be lower than the amount used in this research. Therefore, 45SBG nanopowders with considerable antibacterial activity could be used as a good candidate for biomedical applications.
https://scientiairanica.sharif.edu/article_4146_20aa7a324744ce07a1026f6206c1914e.pdf
2017-06-01
1706
1716
10.24200/sci.2017.4146
Bioactive glass nanopowders
Antibacterial properties
Cytotoxicity
Sol-gel technique
Sh.
Soltani-Dehnavi
1
Department of New Science and Technology Campus (Biomaterial Group), Semnan University, Semnan, P.O. Box 35131-19111, Iran
AUTHOR
M.
Mehdikhani-Nahrkhalaji
2
Department of Biomedical Engineering, Faculty of Engineering, University of Isfahan, Isfahan, P.O. Box 81746-13441, Iran
LEAD_AUTHOR
M.
Rafienia
3
Biosensor Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
AUTHOR
A.
Doostmohammadi
4
Department of Materials, Faculty of Engineering, Shahrekord University, Shahrekord, Iran
AUTHOR
ORIGINAL_ARTICLE
Synthesis and antimicrobial properties of ZnO/PVA, CuO/PVA, and TiO2/PVA nanocomposites
In this paper, zinc oxide (ZnO), copper oxide (CuO), and titanium oxide (TiO2) nanoparticles were prepared using sol-gel method. The structural properties of these nanoparticles were characterized using X-Ray Diraction (XRD) and Transmission Electron Microscopy (TEM). SEM images revealed that the average sizes of zinc oxide, copper oxide, and titanium oxide nanoparticles are about 37 nm, 86 nm, and 50 nm, respectively. Then, nanocomposites of metal oxide were produced by Polyvinyl Alcohol (PVA). The antibacterial activities of zinc oxide, copper oxide, and titanium oxide nanocomposites against human pathogenic bacteria, mainly Escherichia coli HB101 (gram-negative), have been studied using drop test during the time periods of 15 minutes, 30 minutes, 1 hour, 2 hours, 12 hours, and 24 hours of generated reviews. According to the results obtained with the nanocomposite, zinc oxide nanoparticles exhibit the highest antibacterial properties.
https://scientiairanica.sharif.edu/article_4147_905ee85512a7e540d84718b40766e20c.pdf
2017-06-01
1717
1723
10.24200/sci.2017.4147
Nanoparticles
Sol-gel method
Polyvinyl alcohol (PVA)
Nano-composites
Antibacterial activity
Drop test method
R.
Etefagh
1
Department of Physics, University of Guilan, Rasht 41335, Iran
LEAD_AUTHOR
S.M.
Rozati
2
Department of Physics, University of Guilan, Rasht 41335, Iran
AUTHOR
E.
Azhir
3
Departments of Physics, Ferdowsi University of Mashhad, Mashhad, Iran.
AUTHOR
N.
Shahtahmasebi
4
Departments of Physics, Ferdowsi University of Mashhad, Mashhad, Iran.
AUTHOR
A.S.
Hosseini
5
Departments of Physics, Ferdowsi University of Mashhad, Mashhad, Iran.
AUTHOR
ORIGINAL_ARTICLE
First-principles study of strain-induced charge polarization in a molybdenum disulfide monolayer
In the presence of elastic planar strain distributions, electronic properties of molybdenum disulde (MoS2) monolayer are investigated within Density Functional Theory (DFT) calculations as implemented in SIESTA package. Three types of planar strain are considered with some dierent intensity values, and uniaxial strain along the armchair and zigzag directions as well as biaxial strain. We present a systematic study of the strained MoS2 monolayer by focusing on the calculation of Total Density Of State (TDOS), Partial Density Of State (PDOS), electron charge density, and electrostatic potential using post processing tools. In most cases, the states due to Mo atoms have dominant association in the TDOS close to the Fermi level of MoS2 monolayer under strain. As a consequence of the strain, S atom takes electron from Mo atom and becomes negatively charged. In addition, the tensile and compressive strains introduce the charge polarization in twoopposite directions per three types of strain for both sheets, which is in line with the experimental study. As another important result, the strain-induced charge polarization is proportional to the intensity value of strain.
https://scientiairanica.sharif.edu/article_4148_54ca9b639eca5bde002b186b906bbbce.pdf
2017-06-01
1724
1733
10.24200/sci.2017.4148
Molybdenum disulfide
Charge polarization
Piezoelectric
Electrostatic potential
N.
Salami
1
Department of Physics, Yasooj Branch, Islamic Azad University, Yasooj, Iran
LEAD_AUTHOR
A.A.
Shokri
2
Department of Physics, Tehran Payame-Noor University, Tehran, P.O. Box 19395-3697, Iran
AUTHOR