Sharif Digital Repository

The process of imaging a biomolecule by atomic force microscope (AFM) is modeled using molecular dynamics (MD) simulations. Since the large normal force exerted by the tip on the biosample in contact and tapping modes may damage the sample structure and produce irreversible deformation, the noncontact mode of AFM (NC-AFM) is employed as the operating mode. The biosample is scanned using a carbon nanotube (CNT) as the AFM probe. CNTs because of their small diameter, high aspect ratio and high mechanical resistance attract many attentions for imaging purposes. The tip-sample interaction is simulated by the MD method. The protein, which has been considered as the biomolecule, is ubiquitin and a... 

In this paper a procedure for two-dimensional unsteady thermo-mechanical analysis of layered structures is presented, allowing the determination of the temperature and stress field at each step the construction period. The finite element method is employed in the methodology. Numerical simulation are focused on concrete structures, particularly roller compacted concrete (RCC) dams. A time varying elasticity modulus is introduced in the model. One case study is presented and analysis under different design approaches. Thermal effects must be considered in the process of designing of certain types of concrete structures in order to prevent the damage during either the construction phase (early... 

The chemical, thermal, and mechanical degradation of polymer chains under high salinity, temperature, and shear rates in oil reservoirs are the current challenges of the polymer flooding process. To answer such a complex requirement, recently, acrylamide (AM)-based thermoassociating graft copolymers (TAP) were synthesized that presented excellent performance as a viscosity enhancer, especially under high temperature and salinity conditions. The purpose of this study was to further investigate the effect of salinity, shear rate, mechanical strength, and adsorption of these TAPs on viscosity-enhancing performance at different temperatures. Finally, the performance of the TAPs was studied in... 

Diatoms are unicellular microalga found in soil and almost every aquatic environment (marine and fresh water). Biogenic silica and diatoms are attractive for biotechnological and industrial applications, especially in the field of biomedicine, industrial/synthetic manufacturing processes, and biomedical/pharmaceutical sciences. Deposition of silica by diatoms allows them to create micro- or nanoscale structures which may be utilized in nanomedicine and especially in drug/gene delivery. Diatoms with their unique architectures, good thermal stability, suitable surface area, simple chemical functionalization/modification procedures, ease of genetic manipulations, optical/photonic... 

Hybrid nanoparticles possess better chemical stability, mechanical resistance, thermal conductivity, physical strength and so forth as equated to pure nanoparticles. The present work describes the novel features of hybrid nanoparticles such as Titanium oxide (TiO2) and Copper (Cu) in the flow of Ethylene glycol (EG) under the induced magnetic field environment. The analysis covers the features of both pure nanofluid Cu/EG and hybrid nanofluid Cu-TiO2/EG. The concentration equation is amended by the activation energy term. The amalgamation of Cu-TiO2/EG exhibits improved and embellished thermal characteristics. A persuasive numerical technique named “Successive over Relaxation” is used to... 

Hybrid nanofluids possess better mechanical resistance, physical strength, chemical stability, thermal conductivity and so forth as compared to individual nanoliquids. Our approach in the present work is to offer a novel study involving MHD flow of hybrid nanoparticles with viscous dissipation effect through a porous medium past a stretching surface. A powerful tool of similarity transformation is utilized to transmute the governing flow model PDEs into ordinary ones. The entire system of nonlinear coupled differential equations along with boundary conditions is tackled numerically by means of Successive over Relaxation (SOR) technique. Two distinctive fluids, named Al2O3-Cu/water (hybrid... 

Hybrid nanoliquids comprise of better physical strength, mechanical resistance, thermal conductivity, and chemical stability as equated to individual nanoliquids. In this paper, MHD hybrid nanoparticle flow with heat and mass transfer attributes is numerically investigated. Flow is taken over a stretching surface embedded in a porous medium. The governing flow model partial differential equations (PDEs) are transformed into ordinary differential equations (ODEs) using a powerful tool of similarity transformations. The relevant system of differential equations and boundary conditions are numerically treated with the successive over-relaxation (SOR) technique. Heat and mass transfer features... 

Hybrid nanoliquids comprise of better physical strength, mechanical resistance, thermal conductivity, and chemical stability as equated to individual nanoliquids. The present work investigates the MHD laminar flow, containing hybrid nanoparticles, with heat transfer phenomenon over a stretching sheet immersed in a porous medium. The effect of induced magnetic field has also been taken into account. The flow model PDEs are rehabilitated into ordinary ones using a persuasive tool of similarity variables. The analogous system of dimensionless equations alongside the boundary conditions is numerically treated with the Successive-Over-Relaxation (SOR) technique. Flow and heat transfer aspects of... 

Hybrid nanoparticles possess better chemical stability, mechanical resistance, thermal conductivity, physical strength and so forth as equated to pure nanoparticles. The present work describes the novel features of hybrid nanoparticles such as Titanium oxide (TiO2) and Copper (Cu) in the flow of Ethylene glycol (EG) under the induced magnetic field environment. The analysis covers the features of both pure nanofluid Cu/EG and hybrid nanofluid Cu-TiO2/EG. The concentration equation is amended by the activation energy term. The amalgamation of Cu-TiO2/EG exhibits improved and embellished thermal characteristics. A persuasive numerical technique named “Successive over Relaxation” is used to... 

Hybrid nanofluids possess better mechanical resistance, physical strength, chemical stability, thermal conductivity and so forth as compared to individual nanoliquids. Our approach in the present work is to offer a novel study involving MHD flow of hybrid nanoparticles with viscous dissipation effect through a porous medium past a stretching surface. A powerful tool of similarity transformation is utilized to transmute the governing flow model PDEs into ordinary ones. The entire system of nonlinear coupled differential equations along with boundary conditions is tackled numerically by means of Successive over Relaxation (SOR) technique. Two distinctive fluids, named Al2O3-Cu/water (hybrid... 

Hybrid nanoliquids comprise of better physical strength, mechanical resistance, thermal conductivity, and chemical stability as equated to individual nanoliquids. In this paper, MHD hybrid nanoparticle flow with heat and mass transfer attributes is numerically investigated. Flow is taken over a stretching surface embedded in a porous medium. The governing flow model partial differential equations (PDEs) are transformed into ordinary differential equations (ODEs) using a powerful tool of similarity transformations. The relevant system of differential equations and boundary conditions are numerically treated with the successive over-relaxation (SOR) technique. Heat and mass transfer features... 

Hybrid nanoliquids comprise of better physical strength, mechanical resistance, thermal conductivity, and chemical stability as equated to individual nanoliquids. The present work investigates the MHD laminar flow, containing hybrid nanoparticles, with heat transfer phenomenon over a stretching sheet immersed in a porous medium. The effect of induced magnetic field has also been taken into account. The flow model PDEs are rehabilitated into ordinary ones using a persuasive tool of similarity variables. The analogous system of dimensionless equations alongside the boundary conditions is numerically treated with the Successive-Over-Relaxation (SOR) technique. Flow and heat transfer aspects of...