33 Questions
Which organization provides movies of a motor and gear train related to MEMS?
Sandia National Laboratory
What are the alternative names for MEMS as mentioned in the text?
Microsystems and Micro-technology (MST)
What are the objectives of the course program as mentioned in the text?
Identify and describe the most commonly used fabrication processes in making MEMS devices
What are students expected to be able to do through the student work in the course program?
List a number of common MEMS transducers and explain their operating principles
What is one of the specific topics covered in the course program according to the text?
MEMS Transducers and Their Operating Principles
What is the focus of the course program according to the text?
An introductory treatment of MEMS, also known as microsystems and micro-technology (MST)
What can students gain experience in, through the course program?
Using English language as a means of expressing technical ideas
What is elastic theory used for, according to the text?
Predicting the stress/strain state of MEMS devices
Which organization provides an overview and objectives for a course on MEMS?
Sandia National Laboratory
What is Sandia National Laboratory's focus according to the text?
MEMS (microsystems and micro-technology) research
Which type of motor can be used in reverse as an actuator?
Comb drive
What is the acronym MEMS used for?
Micro-Electro-Mechanical Systems
What is the basic unit of measure in MEMS?
Micrometer
What do most accelerometers use to sense acceleration?
Electrical capacitance
In which type of device can MEMS accelerometers be widely found?
Automobiles
What is the acronym for 'Focused ion beam instruments'?
FIB
Which book is suggested as a reference for introductory MEMS?
Introductory MEMS: Fabrication and Applications by Thomas Adams and Richard Layton, Springer
What is the working equation for conduction?
$Q = \frac{kA(T1 - T2)}{d}$
Which material has the highest thermal conductivity among the listed options?
Copper
What is the combined heat transfer mode of conduction and advection known as?
Convection
What is the equation for radiation heat transfer?
$Q = \frac{\epsilon_1T_1^4 - \epsilon_2T_2^4}{A}$
What is the equation for convective heat transfer?
$Q̇ = hA(T_1 - T_2)$
What does the symbol $T_∞$ represent in the context of convective heat transfer?
The ambient temperature
What is the equation for heat transfer through radiation for a perfect blackbody?
$Q̇ = \epsilon\sigma A(T_S^4 - T_{sur}^4)$
What does the symbol $T_S$ represent in the context of radiation heat transfer?
The temperature of a small object
In the context of thermal actuators, what does the symbol $ω_{tip}$ represent?
Mechanical output (motion)
What is the equation for voltage drop across the hot arm in terms of input voltage, resistivity, and geometry?
$eρ(L/A_h)$
What is the equation for temperature of the cold arm in terms of input voltage, resistivity, geometry, and heat transfer coefficient?
$T_c = e(A_h + A_c)/A_c$
What is the thermal strain when the hot arm is initially at $T_∞$ and is then heated to $T_h$?
$\alpha T_h (T_h - T_∞)$
In the context of thermal actuators, which arm experiences an extra piece of strain due to being hooked to another component?
Hot arm
What are initial stresses experienced by in a thermal actuator?
Hot arm only.
In thermal actuators, what does ε represent?
Thermal strain.
What does Q̇conv stand for in thermal actuators?
Convective heat transfer.
Study Notes
MEMS Course Overview
- The course provides an overview and objectives for a course on Micro-Electro-Mechanical Systems (MEMS).
- The focus of the course program is on MEMS, which is also known as Micro-Systems Technology (MST) or Micro-Nano Systems.
Objectives and Expectations
- The objectives of the course program include understanding the design, fabrication, and application of MEMS devices.
- Students are expected to be able to design, fabricate, and test MEMS devices through hands-on activities and projects.
MEMS and Applications
- One of the specific topics covered in the course program is the design and fabrication of thermal actuators.
- Students can gain experience in the design, fabrication, and testing of MEMS devices, including thermal actuators.
- MEMS devices are widely used in applications such as accelerometers, which can sense acceleration.
Elastic Theory and Thermal Conductivity
- Elastic theory is used to analyze the thermal strain in thermal actuators.
- The basic unit of measure in MEMS is the micron (μm).
- Materials with high thermal conductivity, such as copper, are used in MEMS devices.
Heat Transfer and Thermal Actuators
- The combined heat transfer mode of conduction and advection is known as convection.
- The equation for radiation heat transfer is Q̇rad = ε * σ * (Ts^4 - T∞^4), where ε is the emissivity and σ is the Stefan-Boltzmann constant.
- The equation for convective heat transfer is Q̇conv = h * A * (Ts - T∞), where h is the heat transfer coefficient and A is the surface area.
- The working equation for conduction is Q̇cond = k * A * (dT/dx), where k is the thermal conductivity and dT/dx is the temperature gradient.
Thermal Actuators and Strain
- In thermal actuators, the hot arm experiences thermal strain due to heating.
- The thermal strain is given by ε = α * ΔT, where α is the thermal expansion coefficient and ΔT is the temperature change.
- The equation for voltage drop across the hot arm is ΔV = I * R, where I is the current and R is the resistance.
- The equation for temperature of the cold arm is Tc = Vin / (R * I), where Vin is the input voltage.
Symbols and Notations
- The symbol T∞ represents the ambient temperature in heat transfer.
- The symbol Ts represents the surface temperature in radiation heat transfer.
- The symbol ε represents the emissivity in radiation heat transfer.
- The symbol ωtip represents the angular frequency in thermal actuators.
Focused Ion Beam Instruments
- The acronym FIB stands for Focused Ion Beam instruments.
References
- The book "MEMS: A Practical Approach" is suggested as a reference for introductory MEMS.
Sandia National Laboratory
- Sandia National Laboratory provides movies of a motor and gear train related to MEMS and focuses on the development of MEMS devices.
Explore movie and still picture galleries featuring motors and gear trains from Sandia National Laboratory, as well as an overview of the course and its objectives.
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