Inertial MEMS

Kempe, Volker

doi:10.1017/cbo9780511933899

Cited by 118 publications

(28 citation statements)

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“…The corresponding boundary conditions are given as:

at \cdot y = 0, \frac{d u_{o u t}}{d y} = 0

at \cdot y = false(h - d false), {(|, u_{i n})}_{y = {(h - d)}^{+}} = {(|, u_{o u t})}_{y = {(h - d)}^{-}}

at \cdot y = false(h - d false), {(|, \frac{d u_{i n}}{d y})}_{y = {(h - d)}^{+}} = {(|, \frac{d u_{o u t}}{d y})}_{y = {(h - d)}^{-}}

Knudsen number

(K n)

, defined as the ratio of molecular mean free path

(λ_{D})

and system characteristic length ( L ), is important for liquid transport in nanochannels as magnitude of

K n

provides an idea of the validity of continuum assumption. For magnitude of

K n < 0.01

, continuum assumption of fluid flow is valid, whereas for

0.01 < K n < 0.1

, slip boundary condition should be incorporated to use the continuum approach . Since, nanofluidic channels may involve

K n \geq 0.01

, slip boundary condition at the wall has been considered in this study as given below:

at \cdot y = h...

…”

Section: Theorymentioning

confidence: 99%

Mass transfer of a neutral solute in polyelectrolyte grafted soft nanochannel with porous wall

Roy

Bhattacharjee

2019

Electrophoresis

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A soft nanochannel involves a soft interface that contains a polyelectrolyte layer (PEL) sandwiched between a rigid surface and a bulk electrolyte solution. Mass transfer of a neutral solute in a combined electroosmotic and pressure driven flow through a polyelectrolyte grafted charged nanochannel with porous wall is presented in this work. Assuming the PEL as fixed charged layer and PEL-electrolyte interface as a semi-penetrable membrane, analytical solutions were obtained for potential distributions (for small wall potential). Velocity profiles were also derived in the same domains, for both inside and outside the PEL. Convective-diffusive species balance equation was semi-analytically solved inside the PEL. Expression of length averaged Sherwood number was also obtained and effects of different parameters, namely, drag parameter (α), Debye parameter (κ ), and PEL thickness were studied in detail. The variation of permeate concentration and permeation flux across the porous wall was obtained.

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“…The corresponding boundary conditions are given as:

at \cdot y = 0, \frac{d u_{o u t}}{d y} = 0

at \cdot y = false(h - d false), {(|, u_{i n})}_{y = {(h - d)}^{+}} = {(|, u_{o u t})}_{y = {(h - d)}^{-}}

at \cdot y = false(h - d false), {(|, \frac{d u_{i n}}{d y})}_{y = {(h - d)}^{+}} = {(|, \frac{d u_{o u t}}{d y})}_{y = {(h - d)}^{-}}

Knudsen number

(K n)

, defined as the ratio of molecular mean free path

(λ_{D})

and system characteristic length ( L ), is important for liquid transport in nanochannels as magnitude of

K n

provides an idea of the validity of continuum assumption. For magnitude of

K n < 0.01

, continuum assumption of fluid flow is valid, whereas for

0.01 < K n < 0.1

, slip boundary condition should be incorporated to use the continuum approach . Since, nanofluidic channels may involve

K n \geq 0.01

, slip boundary condition at the wall has been considered in this study as given below:

at \cdot y = h...

…”

Section: Theorymentioning

confidence: 99%

Mass transfer of a neutral solute in polyelectrolyte grafted soft nanochannel with porous wall

Roy

Bhattacharjee

2019

Electrophoresis

View full text Add to dashboard Cite

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“…The electrostatic force F d alon by g the direction d is given the negative gradient of the stored energy [1] as…”

Section: Mapping From a Physical Plane To A Parallel Stripmentioning

confidence: 99%

“…MEMS technology has been rapidly developed and expanded in the past 30 years in various industries such as automobile, consumer electronic, health, and telecommunication. In 2011, MEMS market reached $12B [1], with MEMS capacitive sensors comprising significant portion of the market. For example, capacitive MEMS are the enabling technology in automobile airbags, accelerometers for cell phones and video game controllers, affordable inertial navigation, etc.…”

Section: Introductionmentioning

confidence: 99%

“…More accurate modeling enables more accurate determination of surface forces due to fringing fields, of dielectric breakdown due to high charge density, gap pull-in instability, comb asymmetry instability, of charge storage for dynamic capacitive circuit element analysis, of capacitance signal to noise ratio, coarse surface profiles, and of parasitic capacitance analysis. Parallel-plate approximation [3] applies to configurations where there is significant electrode overlap within close proximity as to approximate a portion of a parallel plate. Because the expression for the parallel plate approximation is analytical, computation is fast.…”

Section: Introductionmentioning

confidence: 99%

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Online Capacitance Modeling Tool for Conductors Represented as Simply-Connected Polygonal Geometries in 2D

Li¹,

Clark²

2012

JST

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We present an online tool for calculating the capacitance between two conductors represented as simply-connected polygonal geometries in 2D with Dirichlet boundaries and homogeneous dielectric. Our tool can be used to model the so-called 2.5D geometries, where the 3rd dimension can be extruded out of plane. Micro-electro-mechanical systems (MEMS) with significant facing surfaces may be approximated with 2.5D geometry. Our tool compares favorably in accuracy and speed to the finite element method (FEM). We achieve modeling accuracy by treating the corners exactly with a Schwarz-Christoffel mapping. And we achieve fast results by not needing to discretize boundaries and subdomains. As a test case, we model a MEMS torsional actuator. Our tool computes capacitance about 1000 times faster than FEM with 4.7% relative error

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“…Sensors are compared with each other on the basis of certain performance factors, such as bias and scale factor stability and repeatability or noise (e.g. random walk) [158,159]. One of the main determining factors in choosing sensors is often the budget of the project.…”

mentioning

confidence: 99%

L1 adaptive control augmentation for a hypersonic glider

Banerjee¹

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ii ABSTRACTThe aim of this research is to investigate control strategies to carry out a pull out of a ballistic trajectory (initially the same as the sub-orbital ballistic HyShot and HIFiRE trajectories) and a pulsed roll angle bank manoeuvre for a hypersonic glider. This study investigates the performance of two different control methodologies in the presence of aerodynamic, gravimetric and actuator uncertainties: pole placement control (PPC) (as the baseline) and adaptive control (to augment the PPC).Through simulations, it is shown that the PPC carries out the pull up manoeuvre (by tracking the flight path angle, ) on a scaled Generic Hypersonic Aerodynamics Model Example (GHAME model). Once the pull-up manoeuvre is carried out the lateral/directional PPCs perform satisfactorily in tracking the commanded roll angle, and maintaining a sideslip angle, , of zero degrees. The PPCs presented are all SingleInput Single Output (SISO) controllers. Pole-zero plots are utilised to highlight the stability properties of the PPC. All the controllers are stable. The differences in the performance and robustness for the various uncertainty cases are highlighted through the tracking error norm and the time delay margin (TDM). The performance of the PPC significantly worsens in the presence of uncertainties. This deterioration is quantified using tracking error norms, error dynamics acceleration and a control surface metric.adaptive control is employed as a control strategy to augment the PPC as it allows the decoupling of the control and the estimation loop. The control augmentation design is employed for both the longitudinal and the lateral/directional channels in the presence of matched and unmatched uncertainties. A piecewise constant adaptive law (to estimate the uncertainties) is adopted for all the channels. An additional challenge present in this research is that the flight path angle dynamics of the system display non-minimum phase behaviour. The control theory requires the inversion of the system dynamics, which renders the control law, which cancels the unmatched uncertainties, unstable. An inverse ABSTRACT iii DC gain method is presented and tested. Using this modification, the inversion of the system dynamics is avoided. The main step forward that has been taken in this thesis is the extension of the application of theory and its application to a non-minimum phase state feedback Linear Time Varying (LTV) systems. This modified law prevents a reformulation of the control problem, for example computing an alternative representation of the state estimator in the augmented controller in order to have all the uncertainties come in through the matched channel of the system or having a virtual inertial measurement unit (IMU) in order to make the measured values minimum phase. The augmented controller is able to cancel the uncertainties and is able to restore the performance of the controller and bring the system closer to the desired system performance. The improvement provided by the augmented controller is d...

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Inertial MEMS

Cited by 118 publications

References 0 publications

Mass transfer of a neutral solute in polyelectrolyte grafted soft nanochannel with porous wall

Mass transfer of a neutral solute in polyelectrolyte grafted soft nanochannel with porous wall

Online Capacitance Modeling Tool for Conductors Represented as Simply-Connected Polygonal Geometries in 2D

L1 adaptive control augmentation for a hypersonic glider

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