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Book part
Publication date: 28 February 2019

Kathy Cousins-Cooper, Dominic P. Clemence-Mkhope, Thomas C. Redd, Nicholas S. Luke and Seong-Tae Kim

Before 2011, student performance rates in college algebra and trigonometry at North Carolina A&T State University (NCA&TSU) were consistently below 50%. To remedy this situation…

Abstract

Before 2011, student performance rates in college algebra and trigonometry at North Carolina A&T State University (NCA&TSU) were consistently below 50%. To remedy this situation, the Mathematics Department implemented the math emporium model (MEM) instructional method. The underlying principle behind MEM is that students learn math by doing math (Twigg, 2011). The MEM requires students to work on math problems and spend more time on material that they do not understand while allowing them to spend less time on material that they do understand. Also, students receive immediate feedback on problems from teaching assistants as they work through their online assignments. After implementing the MEM, student pass rates improved for both the MEM and traditional sections. Data to date also show that female students outperform male students in both instructional models. Further study is needed to determine the factors that have caused improvement in pass rates in addition to the implementation of the MEM. Some important lessons learned by the NCA&TSU math faculty from implementing the MEM into the college algebra and trigonometry courses are that successful implementation requires a long-term commitment, internal and external collaborations, and the collective ability to determine what works for the local setting.

Details

Broadening Participation in STEM
Type: Book
ISBN: 978-1-78756-908-9

Keywords

Article
Publication date: 1 April 2003

Patrick Bell, Nils Hoivik, Victor Bright and Zoya Popovic

A frequency tunable half‐wave resonator at 3 GHz is presented with a microelectromechanical systems (MEMS) variable capacitor as the tuning element. The capacitor is fabricated…

Abstract

A frequency tunable half‐wave resonator at 3 GHz is presented with a microelectromechanical systems (MEMS) variable capacitor as the tuning element. The capacitor is fabricated using the multi‐user MEMS process (MUMPs) technology provided by JDS/Cronos, and transferred to an alumina substrate by an in‐house developed flip‐chip process. This capacitor is electrostatically actuated. The resulting CV response is linear with a slope of 0.05 pF/V for a wide range of actuation voltages. The MEMS device has a capacitance ratio of 3:1 for 0‐70 V bias, with a Q‐factor of 140 measured at 1 GHz. A half‐wave tunable microstrip resonator with bias lines is designed to include this MEMS device, which exhibits linear tuning over 180 MHz (6 percent) centered around 3 GHz with a constant 3 dB bandwidth of 160 MHz over the entire tuning range. The power consumption of the MEMS device was measured to be negligible.

Details

Microelectronics International, vol. 20 no. 1
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 6 September 2011

John Lee, Scott Newbern, Yu‐Chong Tai, Chih‐Ming Ho and Po‐Hao Adam Huang

The goal of this research is to demonstrate micro‐electro‐mechanical systems (MEMS)‐based transducers for aircraft maneuvering. Research in wind tunnels have shown that…

Abstract

Purpose

The goal of this research is to demonstrate micro‐electro‐mechanical systems (MEMS)‐based transducers for aircraft maneuvering. Research in wind tunnels have shown that micro‐actuators can be used to manipulate leading edge vortices found on aerodynamic surfaces with moderate to highly swept leading edges, such as a delta wing. This has been labeled as the MEMS vortex shift control (MEMS‐VSC). The work presented in this paper seeks to detail the evolution of real‐world flight tests of this research using remotely piloted vehicles (RPVs).

Design/methodology/approach

Four different RPVs were constructed and used for flight tests to demonstrate the ability of using MEMS devices to provide flight control, primarily in the rolling axis.

Findings

MEMS devices for high angle‐of‐attack (AOA) turning flights have been demonstrated and the paper finds that the success of a complex project like the MEMS‐VSC requires the marriage of basic science expertise found in academia and the technical expertise found in industry.

Research limitations/implications

Owing to the need to test fly the RPVs at low altitudes for video documentation while performing high AOA maneuvers, the attrition of the RPVs becomes the dominant factor to the pace of research.

Practical implications

MEMS sensors and actuators can be used to augment flight control at high AOA, where conventional control surfaces typically experiences reduced effectiveness. Separately, the lessons learned from the integration efforts of this research provide a potentially near parallel case study to the development of ornithopter‐based micro aerial vehicles.

Originality/value

This is the only research‐to‐date involving the demonstration of the MEMS‐VSC on real‐world flight vehicles.

Details

Aircraft Engineering and Aerospace Technology, vol. 83 no. 5
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 March 2002

Michael Huff

Describes the key attributes of MEMS technology and existing and future business opportunities. Discusses the various stages in the fabrication of MEMS devices and offers guidance…

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Abstract

Describes the key attributes of MEMS technology and existing and future business opportunities. Discusses the various stages in the fabrication of MEMS devices and offers guidance regarding the selection of processing methods for deposition, lithography and etching. Also describes the MEMS‐Exchange program and associated network of fabrication centres.

Details

Sensor Review, vol. 22 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 26 June 2019

Pavel Baranov, Tamara Nesterenko, Evgenii Barbin, Aleksej Koleda, Shuji Tanaka, Takashiro Tsukamoto, Ivan Kulinich, Dmitry Zykov and Alexander Shelupanov

Technological capabilities of manufacturing microelectromechanical system (MEMS) gyroscopes are still insufficient if compared to manufacturing high-efficient gyroscopes and…

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Abstract

Purpose

Technological capabilities of manufacturing microelectromechanical system (MEMS) gyroscopes are still insufficient if compared to manufacturing high-efficient gyroscopes and accelerometers. This creates weaknesses in their mechanical structure and restrictions in the measurement accuracy, stability and reliability of MEMS gyroscopes and accelerometers. This paper aims to develop a new architectural solutions for optimization of MEMS gyroscopes and accelerometers and propose a multi-axis MEMS inertial module combining the functions of gyroscope and accelerometer.

Design/methodology/approach

The finite element modeling (FEM) and the modal analysis in FEM are used for sensing, drive and control electrode capacitances of the multi-axis MEMS inertial module with the proposed new architecture. The description is given to its step-by-step process of manufacturing. Algorithms are developed to detect its angular rates and linear acceleration along three Cartesian axes.

Findings

Experimental results are obtained for eigenfrequencies and capacitances of sensing, drive and control electrodes for 50 manufactured prototypes of the silicon electromechanical sensor (SES). For 42 SES prototypes, a good match is observed between the calculated and simulated capacitance values of comb electrodes. Thus, the mean-square deviation is not over 20 per cent. The maximum difference between the calculated and simulated eigenfrequencies in the drive channel of 11 SES prototypes is not over 3 per cent. The same difference is detected for eigenfrequencies in the first sensing channel of 17 SES prototypes.

Originality/value

This study shows a way to design and optimize the structure and theoretical background for the development of the MEMS inertial module combining the functions of gyroscope and accelerometer. The obtained results will improve and expand the manufacturing technology of MEMS gyroscopes and accelerometers.

Details

Sensor Review, vol. 39 no. 5
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 1 November 2005

Kevin Davis

This paper reviews experience with credit union demutualisation to date in the light of increasing discussion about whether demutualisation is a likely (or inevitable) future…

Abstract

This paper reviews experience with credit union demutualisation to date in the light of increasing discussion about whether demutualisation is a likely (or inevitable) future stage in the evolutionary process. It is argued that the credit union industry faces an inherent demutualisation bias which emerges as the sector develops maturity. Contributing factors include the emergence of professional management pursuing personal objectives, together with the economic realities of technological change, financial liberalisation, increased competition, and prudential regulation based on minimum capital requirements. Demutualisation incentives may partially reflect the unsuitability of the mutual form of governance in larger, more sophisticated financial institutions, but there is also a significant risk of demutualisation based on wealth expropriation motives. Alternative policies and strategies which might avoid this demutualisation bias are examined.

Details

Managerial Finance, vol. 31 no. 11
Type: Research Article
ISSN: 0307-4358

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Article
Publication date: 30 January 2007

Robert Bogue

To describe the historical development of micro‐electromechanical system (MEMS) sensor technology, to consider its current use in physical, gas and chemical sensing and to…

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Abstract

Purpose

To describe the historical development of micro‐electromechanical system (MEMS) sensor technology, to consider its current use in physical, gas and chemical sensing and to identify and discuss future technological trends and directions.

Design/methodology/approach

This paper identifies the early research which led to the development of MEMS sensors. It considers subsequent applications of MEMS to physical, gas and chemical sensing and discusses recent technological innovations.

Findings

This paper illustrates the greatly differing impacts exerted on physical, gas and chemical sensing by MEMS technology. More recent developments are discussed which suggest strong market prospects for MEMS devices with analytical capabilities such as microspectrometers, micro‐GCs, microfluidics, lab‐on‐a‐chip and BioMEMS. This view is supported by various market data and forecasts.

Originality/value

This paper provides a technical and commercial insight into the applications of MEMS technology to physical and molecular sensors from the 1960s to the present day. It also identifies high growth areas for innovative developments in the technology.

Details

Sensor Review, vol. 27 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 16 November 2012

Mark Bachman and G.P. Li

The purpose of this paper is to present the utilities of packaging and PCB fabrication processes for manufacturing micro electromechanical systems (MEMS) and its package for…

Abstract

Purpose

The purpose of this paper is to present the utilities of packaging and PCB fabrication processes for manufacturing micro electromechanical systems (MEMS) and its package for sensing and actuation applications.

Design/methodology/approach

A broad array of manufacturing approaches available in the packaging industry, including lamination, lithography, etching, electroforming, machining, bonding, etc. and a large number of available functional materials such as polymers, ceramics, metals, etc. were explored for producing functional microdevices with greater design freedom.

Findings

Good quality MEMS devices can be manufactured using packaging style fabrication, particularly using stacks of laminates. Furthermore, such microdevices can be built with a high degree of integration, pre‐packaged, and at low cost.

Research limitations/implications

Further manufacturing research work should be undertaken in collaboration with the PCB and packaging industries, which stand to benefit greatly by expanding their offerings beyond serving the semiconductor industry and developing their own integrated MEMS products.

Originality/value

The paper presents examples of basic packaging fabrication processes for producing 3‐D structures and free‐standing structures, and a new MEMS manufacturing paradigm to build micro‐electromechanical (MEMS) for biomedical, optical, and RF communication applications.

Article
Publication date: 3 January 2017

Peyman Rafiee, Golta Khatibi and Michael Zehetbauer

The purpose of this paper is to provide an overview of the major reliability issues of microelectromechanical systems (MEMS) under mechanical and environmental loading conditions…

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Abstract

Purpose

The purpose of this paper is to provide an overview of the major reliability issues of microelectromechanical systems (MEMS) under mechanical and environmental loading conditions. Furthermore, a comprehensive study on the nonlinear behavior of silicon MEMS devices is presented and different aspects of this phenomenon are discussed.

Design/methodology/approach

Regarding the reliability investigations, the most important failure aspects affecting the proper operation of the MEMS components with focus on those caused by environmental and mechanical loads are reviewed. These studies include failures due to fatigue loads, mechanical vibration, mechanical shock, humidity, temperature and particulate contamination. In addition, the influence of squeeze film air damping on the dynamic response of MEMS devices is briefly discussed. A further subject of this paper is discussion of studies on the nonlinearity of silicon MEMS. For this purpose, after a description of the basic principles of nonlinearity, the consequences of nonlinear phenomena such as frequency shift, hysteresis and harmonic generation and their effects on the device performance are reviewed. Special attention is paid to the mode coupling effect between the resonant modes as a result of energy transfer because of the nonlinearity of silicon. For a better understanding of these effects, the nonlinear behavior of silicon is demonstrated by using the example of Si cantilever beams.

Findings

It is shown that environmental and mechanical loads can influence on proper operation of the MEMS components and lead to early fracture. In addition, it is demonstrated that nonlinearity modifies dynamic response and leads to new phenomena such as frequency shift and mode coupling. Finally, some ideas are given as possible future areas of research works.

Originality/value

This is a review paper and aimed to review the latest manuscripts published in the field of reliability and nonlinearity of the MEMS structures.

Details

Microelectronics International, vol. 34 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 17 August 2021

Muhammad Ahmad Raza Tahir, Muhammad Mubasher Saleem, Syed Ali Raza Bukhari, Amir Hamza and Rana Iqtidar Shakoor

This paper aims to present an efficient design approach for the micro electromechanical systems (MEMS) accelerometers considering design parameters affecting the long-term…

Abstract

Purpose

This paper aims to present an efficient design approach for the micro electromechanical systems (MEMS) accelerometers considering design parameters affecting the long-term reliability of these inertial sensors in comparison to traditional iterative microfabrication and experimental characterization approach.

Design/methodology/approach

A dual-axis capacitive MEMS accelerometer design is presented considering the microfabrication process constraints of the foundry process. The performance of the MEMS accelerometer is analyzed through finite element method– based simulations considering main design parameters affecting the long-term reliability. The effect of microfabrication process induced residual stress, operating pressure variations in the range of 10 mTorr to atmospheric pressure, thermal variations in the operating temperature range of −40°C to 100°C and impulsive input acceleration at different input frequency values is presented in detail.

Findings

The effect of residual stress is negligible on performance of the MEMS accelerometer due to efficient design of mechanical suspension beams. The effect of operating temperature and pressure variations is negligible on energy loss factor. The thermal strain at high temperature causes the sensing plates to deform out of plane. The input dynamic acceleration range is 34 g at room temperature, which decreases with operating temperature variations. At low frequency input acceleration, the input acts as a quasi-static load, whereas at high frequency, it acts as a dynamic load for the MEMS accelerometer.

Originality/value

In comparison with the traditional MEMS accelerometer design approaches, the proposed design approach focuses on the analysis of critical design parameters that affect the long-term reliability of MEMS accelerometer.

Details

Microelectronics International, vol. 38 no. 4
Type: Research Article
ISSN: 1356-5362

Keywords

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