Continuous Particle Separation Driven by 3D Ag-PDMS Electrodes with Dielectric Electrophoretic Force Coupled with Inertia Force

Cell separation has become @important in biological and medical applications. Dielectrophoresis (DEP) is widely used due to the advantages it offers, such as the lack of a requirement for biological markers and the fact that it involves no damage to cells or particles. This study aimed to report a novel approach combining 3D sidewall electrodes and contraction/expansion (CEA) structures to separate three kinds of particles with different sizes or dielectric properties continuously. The separation was achieved through the interaction between electrophoretic forces and inertia forces. The CEA channel was capable of sorting particles with different sizes due to inertial forces, and also enhanced the nonuniformity of the electric field. The 3D electrodes generated a non-uniform electric field at the same height as the channels, which increased the action range of the DEP force. Finite element simulations using the commercial software, COMSOL Multiphysics 5.4, were performed to determine the flow field distributions, electric field distributions, and particle trajectories. The separation experiments were assessed by separating 4 µm polystyrene (PS) particles from 20 µm PS particles at different flow rates by experiencing positive and negative DEP. Subsequently, the sorting performances of the 4 µm PS particles, 20 µm PS particles, and 4 µm silica particles with different solution conductivities were observed. Both the numerical simulations and the practical particle separation displayed high separating efficiency (separation of 4 µm PS particles, 94.2%; separation of 20 µm PS particles, 92.1%; separation of 4 µm Silica particles, 95.3%). The proposed approach is expected to open a new approach to cell sorting and separating.

Multistable autonomous motion of fruit on a smooth hotplate

Origin of scale coupling may be clarified by the understanding of multistability, or shifts between stable points via unstable equilibrium points due to a stimulus. When placed on a glasstop hotplate, cobs of corn underwent multistable autonomous oscillation, with unsteady viscous lubrication below and transitional plumes above, where the buoyancy to inertia force ratio is close to ≥ 1.0. Subsequently, viscous wall-frictional multistability occurred in six more types of smooth fruit with nominal symmetry. Autonomous motion observed are: cobs roll, pitch and yaw; but green chillies, blueberries, tropical berries, red grapes, oblong grapes and grape tomatoes roll and yaw. The cross products of the orthogonal angular momentum produce the observed motion. The prevalence of roll and yaw motion are the most common. Lubricant film thickness h$$\propto$$ ∝ U/(TF), for cob mass F, tangential velocity U and temperature T. In heavier cobs, the film thins, breaking frequently, changing stability. Lighter cobs have high h, favoring positive feedback and more spinning: more T rises, more viscosity of water drops, increasing U and h more, until cooling onsets. Infrequent popping of the tender corn kernel has the same mean sound pressure level as in hard popcorn. The plume vortex jets lock-in to the autonomous rolling cob oscillation. Away from any solid surface, the hot-cold side boundary produces plumes slanted at ± 45°. Surface fencing (13–26 μm high) appears to control motion drift.

Experimental Investigation on Dynamic Performance of Micro-Pile with Predrilled Oversize Hole on Shaking Table Test

For the situation of lacking research on micro-pile with predrilled oversize hole, the key part of semi-integral abutment bridge, the micro-pile-soil interaction shaking table test is carried out by considering the reaming pore diameter, depth, packing and other parameters in the end of the micro-pile to obtain the acceleration, pile moment, displacement and pile-system response frequency and other basic dynamic response and dynamic interaction law. Results show that: 1) the change of predrilled-hole parameters has litter effect on the dynamic properties of soil outside oversize hole; 2) The change of predrilled-hole parameters can cause the change of structural frequency, so led to the change of inertia force of pile head; 3) Inertial interaction has an important influence on the response of the upside part of pile and little influence in the downside part (lower than 15D). These conclusions will provide reference for dynamic response of interaction between pile with predrilled oversize hole and soil and make contribution to the practical application and designing of micro-pile with predrilled oversize hole.

Review on the Performance Evaluation of Thermal Exchangers using Different Baffle Designs

The thermal performance of a heat exchanger depends upon various parameters like inlet temperature of hot fluid, type of hot fluid, type of cold fluid, the shape of baffles, the material of baffles, baffles angle, and property of ribs. Basically fluid flow and heat transfer characteristics largely depend upon the Reynolds number (Re). Reynolds number is basically the ratio of inertia force to viscous force. Re is only the factor by which we can decide whether the fluid is laminar or turbulent in shell and tube type of heat exchanger. The heat exchanger is an adiabatic device in which heat is transferred from one fluid to another fluid across a plate surface. In this paper, we have introduced some special types of triangular baffles with rectangular channels. The purpose of this apparatus is to enhance the performance of the heat exchanger. Heat exchangers, nowadays, are one of the most important heat & mass transfer apparatuses in industries like oil refining; heat treatment plants, electric power generation, etc. are long service life.

Simulation of а car parameters impact on the process of its acceleration

Goal. The purpose of the work is mathematical modeling of Daewoo Lanos passenger car acceleration dynamics. Methodology. The mathematical model is based on the methodology of E.A. Chudakov and N.A.Yakovlev. According to this method, the main factor that determines the current value of vehicle acceleration at an elementary speed section is the dynamic factor. This factor depends on the traction force, the air resistance force and the weight of the vehicle. The paper proposes formulas for determining the dynamic factor and parameters of vehicle acceleration at an elementary speed section, where gear shift takes place. The model is implemented in the MATLAB software environment. The software product allows to determine the parameters of the car during acceleration to the maximum speed when the engine is running at the external speed characteristic modes. Results Based on the results of mathematical modeling for the Daewoo Lanos car, the loads arising in the drive of the car were analyzed. It is shown that the tractive effort is mainly spent on overcoming the inertial forces, which at the beginning of the movement exceed the resistance forces of the road and air by more than 50 times. With an increase in the vehicle speed, the inertia force decreases and at a speed of 100 km / h it is only twice the other load components. It is shown that with the accepted initial data, the Daewoo Lanos car accelerates to 100 km/h in 17.7 s, which corresponds to the experimental data. The influence of the mass of the car, the rated power of the engine, the mode and time of gear shifting, the radius of the wheels, the height of the car, the coefficient of aerodynamic drag on the dynamics of acceleration of the car is analyzed. It was revealed that the vehicle weight and the nominal power of the engine affect the dynamics of acceleration from 0 to 100 km/h to the greatest extent. The influence of other parameters in the indicated speed range is not somewhat significant. The explanation of the obtained results is given. Practical value. The mathematical model presented in the work allows to determine the parameters of the engine and the car during acceleration, take into account the influence of the design and adjusting parameters of the engine and the car on these indicators, and carry out optimization studies.

Dynamics modelling and analysis of a large-load swinging platform

Swing platform is widely used to simulate the motion attitude of vehicles, ships and aircraft while carrying large loads. Aiming at the excessive driving force and output power of the driving parts caused by the large load swing platform, a new swing platform which can bear the large load was established. The swing platform is equipped with four spring branch chains between the moving platform and the static platform of the 6-UPS parallel mechanism, so as to offset the gravity of the large load and the inertia force of the large load in the process of motion, and the driving force of each branch chain is reduced. In this paper, the structure of the swing platform is introduced, and the dynamics of the swing platform is modeled using the Newton-Euler dynamics equation. Finally, the driving force of each branch chain of the swing platform is obtained by simulation of the dynamics of the swing platform. The simulation results show that the swing platform with four spring branch chains can effectively reduce the driving force of each branch chain compared with the traditional 6-UPS parallel mechanism swing platform.

Comparative Study of Seismic Acceleration Amplification Models for RC Frame Structures

As the current aspect, the nonstructural components (NSCs) linked with the structures are more affected during the seismic motion. It causes not only loss of the economy but also affected life. The various codal provision has been available for minimizing the damages of primary components, but for NSCs, a minimal requirement is functional. So that more investigation is required for understating the behavior of NSCs during the seismic motion. The research aims to understand the behavior of acceleration demand on NSCs in a building. Structures subjected to inertia forces due to earthquakes experience damage of nonstructural components (NSC). The inertia force acting the NSCs are related to acceleration amplification factor. For obtaining the peak horizontal floor acceleration with respect to tectonic ground motion, these factors are used. In this paper, mathematical models of the acceleration amplification factor defined as the peak floor acceleration with respect to peak ground acceleration, given by previous researchers, has been compared. For this 2,4,6,8 and 10 storey moment-resisting frame models considering 29 ground motion data ranging between 0.1g to 0.2g, is analyzed using linear time history method. The supports of the models are considered fixed. The ETABS software is used for the analysis of the models. To analyses the models, the modal mass participation ratio plays a significant role. ASCE 7-05 defines that the structure should be investigated and designed when the model mass participation ratio is equal to or more than 90 per cent. Based on the results, a comparison of the reported models is made. There is a strong need for further research to refine the models for the realistic prediction of acceleration amplification factor.

Research and Application of Flutter Suppression Technology for Aeroengine Case Machining

The magazine is an important part of the aero-engine, its main role is to bear the load and mass inertia force generated by the engine in the work. The design and manufacturing level of the magazine is of great significance to improve the aero-engine’s quality. Engine magazine belongs to a thin-wall cylinder part with large size, complex shape and high processing precision. Due to its thin wall rigidity difference, the processing quality is easy to reduce caused by the vibration of machine tools and other processing system, and cannot meet the requirements. According to the absorption principle of TMD (Tuning Mass Damper), an auxiliary fixture is designed to transfer the magazine processing vibration energy to the auxiliary fixture to reduce the vibration of the processing system and to improve the processing quality. Through ANSYS analysis, the maximum vibration amplitude of the magazine was reduced by 60% by using this fixture. Therefore, the fixture can significantly reduce the vibration in the processing and have good effect on improving the quality of the processing. The auxiliary fixture has the advantages of simple installation, simple disassembly, and strong scalability.