scholarly journals Bouncing dynamics of electrostatically actuated NEM switches

Nano Express ◽  
2021 ◽  
Author(s):  
Mohamed Bognash ◽  
Samuel F Asokanthan
Keyword(s):  
Contact Time ◽  
Surface Effects ◽  
Intermolecular Forces ◽  
Operating Conditions ◽  
Contact Dynamics ◽  
Interactive System ◽  
Initial Contact ◽  
Performance Parameters ◽  
Electrostatically Actuated ◽  
Switch Performance

Abstract The aim of the present research is to understand the bouncing dynamic behavior of nano electromechanical (NEM) switches in order to improve the switch performance and reliability. It is well known that bouncing can dramatically degrade the switch performance and life; hence, in the present study, the bouncing dynamics of a cantilever-based NEM switch has been studied in detail. To this end, the repulsive van der Waals force is incorporated into a nano-switch model to capture the contact dynamics. Intermolecular forces, surface effects, and gas rarefication effects were also included in the proposed model. The Euler-Bernoulli beam theory and an approximate approach based on Galerkin’s method have been employed to predict transient dynamic responses. In the present study, performance parameters such as initial contact time, permanent contact time, major bounce height, and the number of bounces, were quantified in the presence of interactive system nonlinearities. The performance parameters were used to investigate the influence of surface effects and rarefication effects on the performance of an electrostatically actuated switch. Recommended operating conditions are suggested to avoid excessive bouncing for these types of NEM switches.

Uncertainty Considerations for Nonlinear Dynamics of a Class of MEMS Switches Undergoing Tip Contact Bouncing

2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Mohamed Bognash ◽  
Samuel F. Asokanthan
Keyword(s):  
Design Method ◽  
Actuation Voltage ◽  
Interactive System ◽  
Initial Contact ◽  
Micro Electro Mechanical Systems ◽  
Mems Switches ◽  
Batch Fabrication ◽  
Length Width ◽  
Switch Performance ◽  
Measure Of Performance

Batch fabrication processes used to produce micro-electro-mechanical systems (MEMS) are prone to uncertainties in the system geometrical and contact parameters as well as material properties. However, since the common design method for these systems is typically based on precise deterministic assumptions, it is necessary to get more insight into their variations. To this end, understanding the influences of uncertainties accompanied by these processes on the system performance and reliability is warranted. The present paper focuses on predictions of uncertainty measures for MEMS switches based on the transient dynamic response, in particular, the bouncing behavior. To understand and quantify the influence of pertinent parameters on the bouncing effects, suitable mathematical model that captures the bouncing dynamics as well as the forces that are dominant at this micron scale are employed. Measure of performance in terms of second-order statistics is performed, particularly for the beam as well as beam tip parameters since excessive tip bounce is known to degrade switch performance. Thus, the present study focusses on the influence of uncertainties in the beam tip geometry parameters such as beam tip length/width as well as contact asperity variables such as the area asperity density and the radius of asperities. In addition to beam tip parameters, this study quantifies the effects of uncertainties in Young's modulus, beam thickness as well as actuation voltage. These influences on significant switch performance parameters such as initial contact time and maximum bounce height have been quantified in the presence of interactive system nonlinearities.

Power Test System Development and Dynamic Performance State Estimation Based on Hub Motor Vehicle

2020 ◽  
Vol 13 (2) ◽  
pp. 126-140
Author(s):  
Jing Gan ◽  
Xiaobin Fan ◽  
Zeng Song ◽  
Mingyue Zhang ◽  
Bin Zhao
Keyword(s):  
Real Time ◽  
Dynamic Performance ◽  
Test System ◽  
Operating Conditions ◽  
Motor Vehicles ◽  
Maximum Speed ◽  
Performance Parameters ◽  
Power Performance ◽  
Power Test ◽  
The Real

Background: The power performance of an electric vehicle is the basic parameter. Traditional test equipment, such as the expensive chassis dynamometer, not only increases the cost of testing but also makes it impossible to measure all the performance parameters of an electric vehicle. Objective: A set of convenient, efficient and sensitive power measurement system for electric vehicles is developed to obtain the real-time power changes of hub-motor vehicles under various operating conditions, and the dynamic performance parameters of hub-motor vehicles are obtained through the system. Methods: Firstly, a set of on-board power test system is developed by using virtual instrument (Lab- VIEW). This test system can obtain the power changes of hub-motor vehicles under various operating conditions in real-time and save data in real-time. Then, the driving resistance of hub-motor vehicles is analyzed, and the power performance of hub-motor vehicles is studied in depth. The power testing system is proposed to test the input power of both ends of the driving motor, and the chassis dynamometer is combined to test so that the output efficiency of the driving motor can be easily obtained without disassembly. Finally, this method is used to carry out the road test and obtain the vehicle dynamic performance parameters. Results: The real-time current, voltage and power, maximum power, acceleration time and maximum speed of the vehicle can be obtained accurately by using the power test system in the real road experiment. Conclusion: The maximum power required by the two motors reaches about 9KW, and it takes about 20 seconds to reach the maximum speed. The total power required to maintain the maximum speed is about 7.8kw, and the maximum speed is 62km/h. In this article, various patents have been discussed.

Phosphorus and Nitrogen Removal from Sewage by Modified Honeycomb Cinder

2013 ◽  
Vol 726-731 ◽  
pp. 2931-2935
Author(s):  
Qi Bin Liang ◽  
Yun Gen Liu ◽  
Kun Tian
Keyword(s):  
Nitrogen Removal ◽  
Phosphorus Removal ◽  
Contact Time ◽  
Low Cost ◽  
Ammonia Nitrogen ◽  
Domestic Sewage ◽  
Operating Conditions ◽  
Optimal Conditions ◽  
Batch Experiments ◽  
Adsorption Capacities

The study aimed at phosphorus and nitrogen removal by honeycomb cinder modified with Zinc chloride (ZnCl2). By bench-scale batch experiments, honeycomb cinders with different modification time and ZnCl2 dosage were modified and its adsorption capacities were evaluated by methylence blue as the adsorbate. Under the optimal modification conditions, large amount modified honeycomb cinders were prepared to remove the phosphorus and nitrogen from domestic sewage, which different operating conditions of honeycomb cinders dosage, and contact time were considered. The results show that removal efficiencies of total phosphate (TP), orthophosphate (PO43-P), total nitrogen (TN) and ammonia nitrogen (NH4+-N) could reach 89.9%, 96.7%, 18.9% and 23.3% under the optimal conditions, respectively. Modified honeycomb cinders might be an effective and low cost adsorbent for phosphorus removal.

Mass Transfer of Oxygen in Diffused Aeration Systems

1974 ◽  
Vol 1 (1) ◽  
pp. 71-84 ◽  
Author(s):  
Donald S. Mavinic ◽  
Jatinder K. Bewtra
Keyword(s):  
Mass Transfer ◽  
Oxygen Transfer ◽  
Contact Time ◽  
Transfer Rate ◽  
Oxygen Transfer Rate ◽  
Laboratory Data ◽  
Operating Conditions ◽  
Airflow Rate ◽  
Transfer Coefficients ◽  
Water Characteristics

Starting from the fundamental concepts of mass transfer of gases into liquid, a comprehensive mathematical equation, relating the mass oxygen-transfer rate to the various parameters in diffused aeration systems, is developed.The important variables involved are the liquid film coefficient, temperature, waste water characteristics, bubble size, diffuser submergence, airflow rate, and the contact time. The contact time between the air bubbles and the oxygen absorbing liquid can be varied by changing the operating conditions of the aeration system in terms of the direction of air and liquid movement. Investigations on four such combinations are presented.The influence of the above-mentioned variables, individually or in combination, on the mass oxygen-transfer rate and overall oxygen transfer coefficient are discussed. The presentation is supported with laboratory data collected from aeration studies over a period of 3 years. With proper understanding of the influence of operating parameters on mass transfer coefficients, it should be possible to modify the design and operation of aeration basins in order to obtain increased oxygen transfer.

Dynamic pull-in instability of electrostatically actuated beams incorporating Casimir and van der Waals forces

2010 ◽  
Vol 224 (9) ◽  
pp. 2037-2047 ◽  
Author(s):  
M Moghimi Zand ◽  
M T Ahmadian
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Van Der Waals ◽  
Time Discretization ◽  
Element Model ◽  
Intermolecular Forces ◽  
Governing Equations ◽  
Electrostatically Actuated ◽  
Clamped Beams ◽  
Fringing Fields

In this study, influences of intermolecular forces on the dynamic pull-in instability of electrostatically actuated beams are investigated. The effects of midplane stretching, electrostatic actuation, fringing fields, and intermolecular forces are considered. The boundary conditions of the beams are clamped—free and clamped—clamped. A finite-element model is developed to discretize the governing equations, and Newmark time discretization is then employed to solve the discretized equations. The static pull-in instability is investigated to validate the model. Finally, dynamic pull-in instability of cantilevers and double-clamped beams are studied considering the Casimir and van der Waals effects. The results indicate that by increasing the Casimir and van der Waals effects, the effect of inertia on pull-in values considerably increases.

scholarly journals Treatment of industrial electroplating wastewater for metals removal via electrocoagulation continous flow reactors

2022 ◽  
Author(s):  
Hussein I. Abdel-Shafy ◽  
Rehan M. M. Morsy ◽  
Mahmoud A. I. Hewehy ◽  
Taha M. A. Razek ◽  
Maamoun M. A. Hamid
Keyword(s):  
Stainless Steel ◽  
Ferric Chloride ◽  
Contact Time ◽  
Removal Rate ◽  
Operating Conditions ◽  
Synthetic Wastewater ◽  
Optimum Operating ◽  
Chemical Coagulation ◽  
Electroplating Wastewater ◽  
Metals Removal

Abstract A real industrial electroplating rinsing wastewater was collected and subjected the physical and chemical examination. The study showed that it can be categorized as high strength wastewater, at pH- 2, COD 1430 mg/l, and high level of metals above permissible limits namely: 150, 30, 25, and 2.9 for Ni, Cu, Zn, and Fe mg/l respectively. Therefore, metals must be adequately removed before discharging to avoid any hazardous impact on the environment. Similar synthetic wastewater was prepared to study effect of chemical coagulation for the precipitation of metals. The optimum removal rate was achieved by using a combination of lime and ferric chloride at 100 and 30 mg/l respectively. The chemically treated electroplating wastewater was subjected to an electrocoagulation study. A comparison between iron and stainless-steel electrodes for the removal of metals was investigated. Furthermore, the effect of different electric voltage, and the contact time on metals removal efficiency were also examined. It was found that the optimum removal capacity was achieved when stainless steel electrode was employed in the presence of ferric chloride as coagulant, at 10 volts, 30 min. contact time, and pH 9 for synthetic solution. In a batch treatment system, the real industrial wastewater was treated at the predetermined optimum operating conditions; the removal of metals was 92.1%, 87.8% and 82.9% for Ni. Zn, and Cu respectively. By employing a continuous flow reactor for the treatment of the same real wastewater and under the same operating conditions; metals removal rate increased to 98.9%, 97.4% and 96.6% for Ni. Zn, and Cu respectively. The level of metals in the final treated wastewater copes with Egyptian Environmental Regulation. The overall results confirmed that the electro-coagulation (EC) technology offers an effective alternative process in combination with the conventional chemical coagulation process for reaching high removal performance of toxic metals from the electroplating wastewater. The advantage of EC technique is achieving high treatment efficiency instead of expensive chemical reagents, high construction cost and/or other conventional processes. In addition, the final treated water can be reused for rinsing process in electroplating industry and/or discharging without any environmental hazard effect. It is also recommended to employ solar energy instead of electricity to reduce cost of operation.

scholarly journals Use of cement kiln dust to remove copper from simulated wastewater using the Response surface methodology

2020 ◽  
Vol 13 (3) ◽  
pp. 200-206
Author(s):  
Hanan A. Ibraheem ◽  
Husham M.Al. Tameemi
Keyword(s):  
Response Surface Methodology ◽  
Contact Time ◽  
Copper Ion ◽  
Operating Conditions ◽  
Ion Concentration ◽  
Copper Removal ◽  
Cement Kiln Dust ◽  
Cement Kiln ◽  
Simulated Wastewater ◽  
Kiln Dust

Copper removal from simulated wastewater was achieved using Cement Kiln Dust (CKD) as adsorbent. The effects of contact time, pH, initial copper ion concentration, rotational speed, and Cement Kiln Dust (CKD) amount were studied. The best operating conditions were determined by applying a Response Surface Methodology (RSM). The results showed that the copper concentration has the main effect on the efficiency of copper removal followed by time, shaking rate, dosage of cement kiln dust, and pH. The best operating conditions were found to have a pH value of 8, contact time 90 minutes, shaking rate of 300 rpm, copper ion concentration 20 ppm, and a quantity of CKD equivalent to 35 g / l. Based on this optimum condition, 99 % of the efficiency of copper removal was achieved.

scholarly journals Study on Influencing Factors of Adsorption of Methylene Blue on Magnetic Graphene Oxide Composite

2020 ◽  
Vol 218 ◽  
pp. 03035
Author(s):  
Yafeng Li ◽  
Jiacheng Li ◽  
Binxin Zhao
Keyword(s):  
Methylene Blue ◽  
Graphene Oxide ◽  
Contact Time ◽  
Ph Value ◽  
Operating Conditions ◽  
Reaction Conditions ◽  
Magnetic Graphene Oxide ◽  
Oxide Composite ◽  
Magnetic Graphene ◽  
Best Parameter

In order to explore the optimal reaction conditions of magnetic graphene oxide composite materials for the treatment of methylene blue wastewater. By controlling the pH value, contact time, temperature, the amount of adsorbent added for comparative analysis, and finally determine the best operating conditions. The study showed that when the pH value was 7, the contact time was 1440 min, the reaction temperature was 25 ° C, and the dosage of the adsorbent was 0.5 g / L, the treatment effect was the best. Parameter optimization can effectively improve the processing effect.

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