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Thin Silicon MEMS Contact-Stress Sensor

Description: This thin, MEMS contact-stress sensor continuously and accurately measures time-varying, solid interface loads over tens of thousands of load cycles. The contact-stress sensor is extremely thin (150 {mu}m) and has a linear output with an accuracy of {+-} 1.5% FSO.
Date: May 28, 2010
Creator: Kotovksy, J; Tooker, A & Horsley, D
Partner: UNT Libraries Government Documents Department

Micromirror Arrays for Adaptive Optics

Description: The long-range goal of this project is to develop the optical and mechanical design of a micromirror array for adaptive optics that will meet the following criteria: flat mirror surface ({lambda}/20), high fill factor (> 95%), large stroke (5-10 {micro}m), and pixel size {approx}-200 {micro}m. This will be accomplished by optimizing the mirror surface and actuators independently and then combining them using bonding technologies that are currently being developed.
Date: August 7, 2000
Creator: Carr, E.J.
Partner: UNT Libraries Government Documents Department

Digial Technology Qualification Task 2 - Suitability of Digital Alternatives to Analog Sensors and Actuators

Description: The next generation reactors in the U.S. are an opportunity for vendors to build new reactor technology with advanced Instrumentation and Control Systems (control rooms, DCS, etc.). The advances made in the development of many current generation operating reactors in other parts of the world are being used in the design and construction of new plants. These new plants are expected to have fully integrated digital control rooms, computerized procedures, integrated surveillance testing with on-line monitoring and a major effort toward improving the O&M and fault survivability of the overall systems. In addition the designs are also incorporating major improvements in the man-machine interface based on lessons learned in nuclear and other industries. The above relates primarily to the scope of supply in instrumentation and control systems addressed by Chapter 7 of the Standard Review Plan (SRP) NUREG-0800 (Reference 9.5), and the associated Balance of Plant (BOP) I&C systems. This does not relate directly to the actuator and motor, breaker, initiation circuitry, valve position, etc. which is the subject of this report and normally outside of the traditional Distributed Control System (DCS), for both safety and non-safety systems. The recommendations presented in this report will be used as input to I&C research programming for the implementation of lessons learned during the early phases of new build both for large light water reactors (LWR) and also small modular reactors (SMR). This report is intended to support current research plans and provide user (vendor, owner-operator) input to the optimization of these research plans.
Date: September 1, 2012
Creator: Quinn, Ted & Mauck, Jerry
Partner: UNT Libraries Government Documents Department

Considerations For Contractile Electroactive Materials and Actuators

Description: Electroactive polymers (EAPs) that bend, swell, ripple (first generation materials), and now contract with low electric input (new development) have been produced. The mechanism of contraction is not well understood. Radionuclide-labeled experiments, molecular modeling, electrolyte experiments, pH experiments, and an ionic concentration experiment were used to determine the chain of events that occur during contraction and, reciprocally, expansion when the polarity is reversed, in these ionic EAPs. Plasma treatment of the electrodes, along with other strategies, allows for the embedded electrodes and the EAP material of the actuator to work and move as a unit, with no detachment, by significantly improving the metal-polymer interface, analogous to nerves and tendons moving with muscles during movement. Challenges involved with prototyping actuation using contractile EAPs are also discussed.
Date: February 29, 2012
Creator: Lenore Rasmussen, Lewis D. Meixler and Charles A. Gentile
Partner: UNT Libraries Government Documents Department

Electromagnetic rotational actuation.

Description: There are many applications that need a meso-scale rotational actuator. These applications have been left by the wayside because of the lack of actuation at this scale. Sandia National Laboratories has many unique fabrication technologies that could be used to create an electromagnetic actuator at this scale. There are also many designs to be explored. In this internship exploration of the designs and fabrications technologies to find an inexpensive design that can be used for prototyping the electromagnetic rotational actuator.
Date: August 1, 2010
Creator: Hogan, Alexander Lee
Partner: UNT Libraries Government Documents Department

Sensor and actuator considerations for precision, small machines: a review

Description: This article reviews some design considerations for the scaling down in size of instruments and machines with a primary aim to identify technologies that may provide more optimal performance solutions than those, often established, technologies used at macroscopic, or conventional, scales. Dimensional metrology within emerging applications will be considered for meso- through micro-down to nanometer level systems with particular emphasis on systems for which precision is directly related to function. In this paper, attention is limited to some of the more fundamental issues associated with scaling. For example, actuator work or power densities or the effect of noise on the sensor signals can be readily evaluated and provide some guidance in the selection for any given size of device. However, with reductions in scale these parameters and/or phenomena that limit performance may change. Within this review, the authors have tried to assess these complex inter-relationships between performance and scale, again from a fundamental perspective. In practice, it is likely that the nuances of implementation and integration of sensor, actuator and/or mechanism designs will determine functionality and commercial viability of any particular system development.
Date: April 4, 2005
Creator: Smith, S T & Seugling, R M
Partner: UNT Libraries Government Documents Department


Description: A history and project summary of the development of an integrated drilling system using a mud-actuated down-hole hammer as its primary engine are given. The summary includes laboratory test results, including atmospheric tests of component parts and simulated borehole tests of the hammer system. Several remaining technical hurdles are enumerated. A brief explanation of commercialization potential is included. The primary conclusion for this work is that a mud actuated hammer can yield substantial improvements to drilling rate in overbalanced, hard rock formations. A secondary conclusion is that the down-hole mud actuated hammer can serve to provide other useful down-hole functions including generation of high pressure mud jets, generation of seismic and sonic signals, and generation of diagnostic information based on hammer velocity profiles.
Date: December 1, 2005
Creator: Fernandez, John V. & Pixton, David S.
Partner: UNT Libraries Government Documents Department

Optimal dynamic performance for high-precision actuators/stages.

Description: System dynamic performance of actuator/stage groups, such as those found in optical instrument positioning systems and other high-precision applications, is dependent upon both individual component behavior and the system configuration. Experimental modal analysis techniques were implemented to determine the six degree of freedom stiffnesses and damping for individual actuator components. These experimental data were then used in a multibody dynamic computer model to investigate the effect of stage group configuration. Running the computer model through the possible stage configurations and observing the predicted vibratory response determined the optimal stage group configuration. Configuration optimization can be performed for any group of stages, provided there is stiffness and damping data available for the constituent pieces.
Date: July 3, 2002
Creator: Preissner, C.; Lee, S.-H.; Royston, T. J. & Shu, D.
Partner: UNT Libraries Government Documents Department

Intricate Mechanisms-on-a Chip Enabled by 5-Level Surface Micromachining

Description: Surface micromachining generally offers more design freedom than related technologies, and it is the technology of choice for most microelectromechanical applications that require multi-level structures. However, the design flexibility that surface micromachining offers is not without limitations. In addition to determining how to fabricate devices in a planar world, the designer also needs to consider issues such as film quality, thickness, residual stress, topography propagation, stringers, processing limitations, and concerns about surface adhesion [1]. Only a few years ago, these were the types of issues that limited design complexity. As the technology improved, the number of mechanical layers available to the designer became the dominant constraint on system functionality. In response, we developed a 5-level polysilicon fabrication technology [2] that offers an unprecedented level of microelectromechanical complexity with simultaneous increases in system yield and robustness. This paper outlines the application that was the driving force behind this work and describes the first devices specifically designed for and fabricated in this technology. The 5-level fabrication technology developed to support this program is known as SUMMiT-V. Four mechanical layers of polysilicon referred to as polyl, poly2, poly3, and poly4 are fabricated above a polyO electrical interconnect and ground plane layer [2,4]. PolyO is 0.3 pm thick, polyl is 1.0 pm, poly 2 is 1.5 pm, and both poly3 and poly4 are 2.25 pm. All films except polyl and poly2 are separated by 2-pm thick depositions of sacrificial oxide. A 0.5-m sacrificial oxide between polyl and poly2 typically defines the clearance between close mating parts such as hubs and hinges. This entire stack is built on a single crystal substrate with a dielectric foundation of 0.8 pm of nitride over 0.63 m of oxide. Seventeen drawing layer are combined to generate the 14 photolithographic masks used to pattern these films during a 240-step ...
Date: March 30, 1999
Creator: Allen, J.J.; McWhorter, P.J.; Miller, S.L.; Rodgers, M.S.; Smith, J.H. & Sniegowski, J.J.
Partner: UNT Libraries Government Documents Department

Scaling Laws for Mesoscale and Microscale Systems

Description: The set of laws developed and presented here is by no means exhaustive. Techniques have been present to aid in the development of additional scaling laws and to combine these and other laws to produce additional useful relationships. Some of the relationships produced here have yielded perhaps surprising results. Examples include the fifth order scaling law for electromagnetic motor torque and the zero order scaling law for capacitive motor power. These laws demonstrate important facts about actuators in small-scale systems. The primary intent of this introduction into scaling law analysis is to provide needed tools to examine possible areas of the research in small-scale systems and direct research toward more fruitful areas. Numerous examples have been included to show the validity of developing scaling laws based on first principles and how real world systems tend to obey these laws even when many other variables may potentially come into play. Development of further laws may well serve to provide important high-level direction to the continued development of small-scale systems.
Date: August 23, 1999
Creator: Spletzer, Barry
Partner: UNT Libraries Government Documents Department

Bi-Stable Optical Actuator

Description: The present invention is a bi-stable optical actuator device that is depowered in both stable positions. A bearing is used to transfer motion and smoothly transition from one state to another. The optical actuator device may be maintained in a stable position either by gravity or a restraining device.
Date: October 15, 1999
Creator: Holdener, Fred R. & Boyd, Robert D.
Partner: UNT Libraries Government Documents Department

Minimum-Time Trajectory Tracking of an Under-Actuated System

Description: Minimum-time trajectory tracking of an under-actuated mechanical system called the Acrobot is presented. The success of the controller is demonstrated by the fact that the tracking error is reduced by more than an order of magnitude when compared to the open-loop system response. The control law is obtained by linearizing the system about the nominal trajectory and applying differential dynamic programming to the resulting linear time-varying system, while using a weighted sum of the state-deviation and input-deviation as the cost function.
Date: October 26, 1999
Partner: UNT Libraries Government Documents Department

Fabrications of PVDF gratings :final report for LDRD project 79884.

Description: The purpose of this project was to do some preliminary studies and process development on electroactive polymers to be used for tunable optical elements and MEMS actuators. Working in collaboration between Sandia National Labs and The University of Illinois Urbana-Champaign, we have successfully developed a process for applying thin films of poly (vinylidene fluoride) (PVDF) onto glass substrates and patterning these using a novel stamping technique. We observed actuation in these structures in static and dynamic measurements. Further work is needed to characterize the impact that this approach could have on the field of tunable optical devices for sensing and communication.
Date: December 1, 2005
Creator: Rogers, J. A. (University of Illinois, Urbana-Champaign); Carr, Dustin Wade & Bogart, Gregory R.
Partner: UNT Libraries Government Documents Department

Final report : compliant thermo-mechanical MEMS actuators, LDRD #52553.

Description: Thermal actuators have proven to be a robust actuation method in surface-micromachined MEMS processes. Their higher output force and lower input voltage make them an attractive alternative to more traditional electrostatic actuation methods. A predictive model of thermal actuator behavior has been developed and validated that can be used as a design tool to customize the performance of an actuator to a specific application. This tool has also been used to better understand thermal actuator reliability by comparing the maximum actuator temperature to the measured lifetime. Modeling thermal actuator behavior requires the use of two sequentially coupled models, the first to predict the temperature increase of the actuator due to the applied current and the second to model the mechanical response of the structure due to the increase in temperature. These two models have been developed using Matlab for the thermal response and ANSYS for the structural response. Both models have been shown to agree well with experimental data. In a parallel effort, the reliability and failure mechanisms of thermal actuators have been studied. Their response to electrical overstress and electrostatic discharge has been measured and a study has been performed to determine actuator lifetime at various temperatures and operating conditions. The results from this study have been used to determine a maximum reliable operating temperature that, when used in conjunction with the predictive model, enables us to design in reliability and customize the performance of an actuator at the design stage.
Date: December 1, 2004
Creator: Walraven, Jeremy Allen; Baker, Michael Sean; Headley, Thomas Jeffrey & Plass, Richard Anton
Partner: UNT Libraries Government Documents Department

Resonance control in SRF cavities at FNAL

Description: The Lorentz force can dynamically detune pulsed Superconducting RF cavities. Considerable additional RF power can be required to maintain the accelerating gradient if no effort is made to compensate for this detuning. Compensation systems using piezo actuators have been used successfully at DESY and elsewhere to control Lorentz Force Detuning (LFD). Recently, Fermilab has developed an adaptive compensation system for cavities in the Horizontal Test Stand, in the SRF Accelerator Test Facility, and for the proposed Project X.
Date: March 1, 2011
Creator: Schappert, W.; Pischalnikov, Y.; /Fermilab; Scorrano, M. & /INFN, Pisa
Partner: UNT Libraries Government Documents Department

Test of a coaxial blade tuner at HTS FNAL

Description: A coaxial blade tuner has been selected for the 1.3GHz SRF cavities of the Fermilab SRF Accelerator Test Facility. Results from tuner cold tests in the Fermilab Horizontal Test Stand are presented. Fermilab is constructing the SRF Accelerator Test Facility, a facility for accelerator physics research and development. This facility will contain a total of six cryomodules, each containing eight 1.3 GHz nine-cell elliptical cavities. Each cavity will be equipped with a Slim Blade Tuner designed by INFN Milan. The blade tuner incorporates both a stepper motor and piezo actuators to allow for both slow and fast cavity tuning. The stepper motor allows the cavity frequency to be statically tuned over a range of 500 kHz with an accuracy of several Hz. The piezos provide up to 2 kHz of dynamic tuning for compensation of Lorentz force detuning and variations in the He bath pressure. The first eight blade tuners were built at INFN Milan, but the remainder are being manufactured commercially following the INFN design. To date, more than 40 of the commercial tuners have been delivered.
Date: March 1, 2011
Creator: Pischalnikov, Y.; Barbanotti, S.; Harms, E.; Hocker, A.; Khabiboulline, T.; Schappert, W. et al.
Partner: UNT Libraries Government Documents Department

The use of a high-order MEMS deformable mirror in the Gemini Planet Imager

Description: We briefly review the development history of the Gemini Planet Imager's 4K Boston Micromachines MEMS deformable mirror. We discuss essential calibration steps and algorithms to control the MEMS with nanometer precision, including voltage-phase calibration and influence function characterization. We discuss the integration of the MEMS into GPI's Adaptive Optics system at Lawrence Livermore and present experimental results of 1.5 kHz closed-loop control. We detail mitigation strategies in the coronagraph to reduce the impact of abnormal actuators on final image contrast.
Date: December 17, 2010
Creator: Poyneer, L. A.; Bauman, B.; Cornelissen, S.; Jones, S.; Macintosh, B.; Palmer, D. et al.
Partner: UNT Libraries Government Documents Department

Active load control techniques for wind turbines.

Description: This report provides an overview on the current state of wind turbine control and introduces a number of active techniques that could be potentially used for control of wind turbine blades. The focus is on research regarding active flow control (AFC) as it applies to wind turbine performance and loads. The techniques and concepts described here are often described as 'smart structures' or 'smart rotor control'. This field is rapidly growing and there are numerous concepts currently being investigated around the world; some concepts already are focused on the wind energy industry and others are intended for use in other fields, but have the potential for wind turbine control. An AFC system can be broken into three categories: controls and sensors, actuators and devices, and the flow phenomena. This report focuses on the research involved with the actuators and devices and the generated flow phenomena caused by each device.
Date: July 1, 2008
Creator: van Dam, C.P. (University of California, Davis, CA); Berg, Dale E. & Johnson, Scott J. (University of California, Davis, CA)
Partner: UNT Libraries Government Documents Department

Thin Silicon MEMS Contact-Stress Sensor

Description: This thin, MEMS contact-stress (CS) sensor continuously and accurately measures time-varying, solid interface loads in embedded systems over tens of thousands of load cycles. Unlike all other interface load sensors, the CS sensor is extremely thin (< 150 {micro}m), provides accurate, high-speed measurements, and exhibits good stability over time with no loss of calibration with load cycling. The silicon CS sensor, 5 mm{sup 2} and 65 {micro}m thick, has piezoresistive traces doped within a load-sensitive diaphragm. The novel package utilizes several layers of flexible polyimide to mechanically and electrically isolate the sensor from the environment, transmit normal applied loads to the diaphragm, and maintain uniform thickness. The CS sensors have a highly linear output in the load range tested (0-2.4 MPa) with an average accuracy of {+-} 1.5%.
Date: March 22, 2010
Creator: Kotovsky, J; Tooker, A & Horsley, D
Partner: UNT Libraries Government Documents Department


Description: Implanted medical devices such as pacemakers and neural prosthetics require that the electronic components that power these devices are protected from the harsh chemical and biological environment of the body. Typically, the electronics are hermetically sealed inside a bio-compatible package containing feedthroughs that transmit electrical signals, while being impermeable to particles or moisture. We present a novel approach for fabricating one of the highest densities of biocompatible hermetic feedthroughs in alumina (Al{sub 2}O{sub 3}). Alumina substrates with laser machined vias of 200 {micro}m pitch were conformally metallized and lithographically patterned. Hermetic electrical feedthroughs were formed by extruding metal stud-bumps partially through the vias. Hermeticity testing showed leak rates better than 9 x 10{sup -10} torr-l/s. Based on our preliminary results and process optimization, this extruded metal via approach is a high-density, low temperature, cost-effective, and robust method of miniaturizing electrical feedthroughs for a wide range of implantable bio-medical device applications.
Date: March 28, 2012
Creator: Shah, K G; Delima, T; Felix, S; Sheth, H; Tolosa, V; Tooker, A et al.
Partner: UNT Libraries Government Documents Department