Modeling the effect of microstructure on the coupled torsion/bending instability of rotational nano-mirror in Casimir regime

t has been well-established that the physical performance of nano-devices might be affected by the microstructure. Herein, a 2-degree-of-freedom model based on the modified couple stress elasticity is developed to incorporate the impact of microstructure in the torsion/bending coupled instability of rotational nano-electromechanical mirror. The governing equation of the mirror is derived incorporating the effects of electrostatic Coulomb and corrected Casimir forces with the consideration of the finite conductivity of interacting surfaces. Effect of microstructure-dependency on the instability parameters are determined as a function of the microstructure parameter, bending/torsion coupling ratio, vacuum fluctuation parameter and geometrical dimensions. It is found that the bending/torsion coupling substantially affects the stable behavior of the mirrors especially those with long rotational beam elements. Depending on the geometry and material characteristics, the presented model is able to simulate both hardening behavior (due to microstructure) and softening behavior (due to torsion/bending coupling) of the nano-mirror

A 2-DOF microstructure-dependent model for the coupled torsion/bending instability of rotational nanoscanner

It has been well established that the physical performance of nanodevices might be affected by the microstructure. Herein, a two-degree-of-freedom model base on the modified couple stress theory is developed to incorporate the impact of microstructure in the torsion/bending coupled instability of rotational nanoscanner. Effect of microstructure dependency on the instability parameters is determined as a function of the microstructure parameter, bending/torsion coupling ratio, van der Waals force parameter and geometrical dimensions. It is found that the bending/torsion coupling substantially affects the stable behavior of the scanners especially those with long rotational beam elements. Impact of microstructure on instability voltage of the nanoscanner depends on coupling ratio and the conquering bending mode over torsion mode. This effect is more highlighted for higher values of coupling ratio. Depending on the geometry and material characteristics, the presented model is able to simulate both hardening behavior (due to microstructure) and softening behavior (due to torsion/bending coupling) of the nanoscanners. © 2016, Springer-Verlag Berlin Heidelberg

A 2-DOF model for incorporating the effect of microstructure on the coupled torsion/bending instability of nano-mirror in Casimir regime

It has been well-established that the physical performance of nano-devices might be affected by the microstructure. Herein, a 2 degree-of-freedom model based on modified couple stress elasticity is developed to incorporate the impact of microstructure in the torsion/bending coupled instability of rotational nano-scanner. The governing equation of the varactor is derived incorporating the effects of electrostatic Coulomb and corrected Casimir forces with the consideration of the finite conductivity of interacting surfaces. Effect of microstructure-dependency on the instability parameters are determined as a function of the microstructure parameter, bending/torsion coupling ratio, vacuum fluctuation parameter and geometrical dimensions. It is found that the bending/torsion coupling substantially affects the stable behavior of the scanners especially those with long rotational beam elements. Depending on the geometry and material characteristics, the presented model is able to simulate both hardening behavior (due to size phenomenon) and softening behavior (due to torsion/bending coupling) of the nano-mirror

A thermosensitive electromechanical model for detecting biological particles

Miniature electromechanical systems form a class of bioMEMS that can provide appropriate sensitivity. In this research, a thermo-electro-mechanical model is presented to detect biological particles in the microscale. Identification in the model is based on analyzing pull-in instability parameters and frequency shifts. Here, governing equations are derived via the extended Hamilton’s principle. The coupled effects of system parameters such as surface layer energy, electric field correction, and material properties are incorporated in this thermosensitive model. Afterward, the accuracy of the present model and obtained results are validated with experimental, analytical, and numerical data for several cases. Performing a parametric study reveals that mechanical properties of biosensors can significantly affect the detection sensitivity of actuated ultra-small detectors and should be taken into account. Furthermore, it is shown that the number or dimension of deposited particles on the sensing zone can be estimated by investigating the changes in the threshold voltage, electrode deflection, and frequency shifts. The present analysis is likely to provide pertinent guidelines to design thermal switches and miniature detectors with the desired performance. The developed biosensor is more appropriate to detect and characterize viruses in samples with different temperatures

Ion modified water flooding in low-permeable carbonates of Bashkirsky formation in Russia-Tatarstan

© 2020 Saint Petersburg 2020 - Geosciences: Converting Knowledge into Resources. All rights reserved. In this work we studied the effect of ion modified water on recovery factor and injectivity of the Bashkisky formation. For preparation of ion modified water added 5g magnesium sulfate to 100g fresh water. In order to define the effectiveness of ion modified water injection, the oil saturated cores were flooded by fresh water and when water-cut reached 100%, we replaced it with ion modified water. According to the results, recovery factor for fresh water was about 9.5% and pressure drop during injection was 232 kPa. By replacing fresh water with ion modified water recovery factor increased up to 14.5% and pressure drop decreased down to 136 kPa. Flooding simulation showed that by adding magnesium ions to fresh water, scale tendency of CaCO3 salt decreased from 22 to 1.2

Miscible gas injection into the reservoirs for increasing oil production

© 2020 Saint Petersburg 2020 - Geosciences: Converting Knowledge into Resources. All rights reserved. Gas injection into the oil reservoirs is one of the effective methods of increasing oil recovery. The gas injection into the reservoirs when it is fully or partially miscible with oil is a difficult physical process from the point of view of mathematical modelling. The simulation of miscible gas injection process by the simulator could give a recommendation about the amount of required gas, injection pressure and other technological parameters. In this work, an industrial software was used to simulate the miscible gas injection process for an Iranian oil reservoir. We determined the amount of gas injection, total oil and gas production and oil recovery factor in the various scenarios of gas recycling. The simulation results showed that the amount production gas was less than the injection gas. In addition, the total oil production and recovery factor was a function of the amount of miscible gas injection

Simulation investigation of hydraulic fracturing process in the oil reservoirs

© 2020 Saint Petersburg 2020 - Geosciences: Converting Knowledge into Resources. All rights reserved. Hydraulic fracturing is one of the most common methods of formation treatment for increasing the production rate, which can effectively enhance the productivity index. Simulation of hydraulic fracturing before the actual operation can help have the more effective treatment. In this work, the fracture width, which can be crated during hydraulic fracturing process, was simulated depending on the time. In addition, the required injection pressure for an optimum operation was determined at various injection rates. Furthermore, the effect of rock permeability and proppant mass on the productivity index and oil production rate was investigated. The simulation results showed that the optimum injection rate for hydraulic fracturing process is 4 L/s. At this rate, the maximum injection pressure was about 14.3 MPa. Moreover, the highest amount of productivity index was observed at lower values of rock permeability

Argonne National Laboratory Reports

The methodology and numerical values of NUREG-0278 were applied to four decommissioning alternatives for the West Valley Fuel Reprocessing Plant. The cost and impacts of the following four alternatives for the process building, fuel receiving and storage, waste tank farm, and auxiliary facilities were assessed: (1) layaway, (2) protective storage, (3) preparation for alternate nuclear use, and (4) dismantlement. The estimated costs are 5.7, 11, 19, and 31 million dollars, respectively