scholarly journals Significance of the Asymmetry of the Haltere: A Microscale Vibratory Gyroscope

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Rizuwana Parween
Keyword(s):  
Cross Sections ◽  
Strain Difference ◽  
Inertial Force ◽  
High Sensitivity ◽  
Ventral Surface ◽  
Small Scale ◽  
Mode Matching ◽  
Vibratory Gyroscopes ◽  
Vibratory Gyroscope ◽  
Mems Gyroscopes

Nature has evolved a beautiful design for small-scale vibratory gyroscopes in the form of halteres located in the metathorax region of the dipteran flies that detect body rotations based on the Coriolis principle. The specific design of the haltere is in contrast to the existing MEMS vibratory gyroscope, where the elastic beams supporting the proof mass are typically designed with symmetric cross-sections so that there is a mode matching between the actuation and sensing vibrations. The mode matching provides high sensitivity and low bandwidth. Hence, the objective of the manuscript is to understand the mechanical significance of the haltere’s asymmetry. In this study, the distributed Coriolis force and the corresponding bending stress by incorporating the actual mass variations along the haltere length are estimated. In addition, it is hypothesied that sensilla sense the rate of rotation based on the differential strain (difference between the final strain (strain due to the inertial and Coriolis forces) and the reference strain (strain due to inertial force)). This differential strain always occurs either on the dorsal or ventral surface of the haltere and at a distance away from the base, where the campaniform sensilla are located. This study brings out one specific feature—the asymmetric geometry of the haltere structure—that is not found in current vibratory gyroscope designs. This finding will inspire new designs of MEMS gyroscopes that have elegance and simplicity of the haltere along with the desired performance.

Temperature and Humidity Effects on MEMS Vibratory Gyroscope

2011 ◽  
Vol 2011 (DPC) ◽  
pp. 001361-001390 ◽  
Author(s):  
Chandradip Patel ◽  
F. Patrick McCluskey ◽  
David Lemus
Keyword(s):  
Damage Mechanism ◽  
Consumer Electronics ◽  
Vibratory Gyroscopes ◽  
Root Cause ◽  
Vibratory Gyroscope ◽  
In Situ Data ◽  
Aging Test ◽  
Temperature And Humidity ◽  
Mems Gyroscopes ◽  
Gyroscope Sensor

MEMS vibratory gyroscopes are increasingly used in applications ranging from consumer electronics to aerospace and are now one of the most common MEMS products after accelerometers. Despite their widespread use, the performance of MEMS gyroscopes in harsh environments is still under question. While some studies have been conducted to understand the temperature dependent performance of MEMS gyroscopes, the effects of sustained exposure to temperature combined with other harsh environment stresses have not been well researched. Thus, it is necessary to quantify MEMS vibratory gyroscope performance under such conditions. This paper will focus on the combined effects of temperature and humidity only. Performance of the MEMS vibratory gyroscope will be evaluated over time at high temperature and high humidity conditions by conducting an aging test on a COTS (commercial of the shelf) single axis MEMS vibratory gyroscope having an operating temperature range from −40°C to 80°C. The gyroscope sensor will be exposed to 60 °C and 90% RH (Relative humidity) for 500 hours. In-situ data will be monitored to track any shifts in device output. Any permanent changes in the output signal will be traced back to their fundamental root cause damage mechanism.

Combined Temperature and Humidity Effects on MEMS Vibratory Gyroscope Sensor

2011 ◽  
Author(s):  
Chandradip Patel ◽  
Patrick McCluskey
Keyword(s):  
Long Term Effects ◽  
Mems Gyroscope ◽  
Vibratory Gyroscopes ◽  
Vibratory Gyroscope ◽  
Temperature And Humidity ◽  
Mems Gyroscopes ◽  
Zero Rate ◽  
Commercial Off The Shelf

Reliability and long term stability are the greatest challenges for commercialization of MEMS gyroscopes. Their vast use in different applications that required MEMS gyroscopes to function from medium to harsh environments make necessary to evaluate the performance of MEMS gyroscope under those conditions. This paper focuses on the combined long term effects of temperature and humidity on the performance of MEMS vibratory gyroscope. Performance of the MEMS gyroscope was evaluated over time by conducting temperature humidity bias (THB) test on a COTS (commercial off-the-shelf) single axis MEMS vibratory gyroscope having an operating temperature range from −40°C to +85°C. The gyroscope sensors were exposed to 60°C and 90%RH (Relative Humidity) for 500 hours. Six single axis gyroscopes were tested, three with in-situ device calibration and three without in-situ device calibration. Out of three MEMS vibratory gyroscopes tested without in-situ device calibration, it was observed that samples had minimum and maximum in-situ zero rate output (ZRO) drift of 1.3°/s and 2.2°/s respectively over 500 hours. These drifts were disappeared when gyroscope sensors were tested after six months by keeping at room condition. Other three single axis gyroscopes were tested in the same chamber with in-situ device calibration which didn’t show any major performance ZRO drift.

scholarly journals The NUMEN Project: Toward New Experiments with High-Intensity Beams

Universe ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 72
Author(s):  
Clementina Agodi ◽  
Antonio D. Russo ◽  
Luciano Calabretta ◽  
Grazia D’Agostino ◽  
Francesco Cappuzzello ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
High Intensity ◽  
Particle Physics ◽  
Nuclear Physics ◽  
High Sensitivity ◽  
Experimental Information ◽  
Double Charge Exchange ◽  
Superconducting Cyclotron ◽  
Double Charge

The search for neutrinoless double-beta (0νββ) decay is currently a key topic in physics, due to its possible wide implications for nuclear physics, particle physics, and cosmology. The NUMEN project aims to provide experimental information on the nuclear matrix elements (NMEs) that are involved in the expression of 0νββ decay half-life by measuring the cross section of nuclear double-charge exchange (DCE) reactions. NUMEN has already demonstrated the feasibility of measuring these tiny cross sections for some nuclei of interest for the 0νββ using the superconducting cyclotron (CS) and the MAGNEX spectrometer at the Laboratori Nazionali del Sud (LNS.) Catania, Italy. However, since the DCE cross sections are very small and need to be measured with high sensitivity, the systematic exploration of all nuclei of interest requires major upgrade of the facility. R&D for technological tools has been completed. The realization of new radiation-tolerant detectors capable of sustaining high rates while preserving the requested resolution and sensitivity is underway, as well as the upgrade of the CS to deliver beams of higher intensity. Strategies to carry out DCE cross-section measurements with high-intensity beams were developed in order to achieve the challenging sensitivity requested to provide experimental constraints to 0νββ NMEs.

Fluid Flow and Heat Transfer of Liquid Sodium in Small-Scale Heat Sinks With Different Geometries

2021 ◽  
Author(s):  
Mahyar Pourghasemi ◽  
Nima Fathi
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Cross Sections ◽  
Heat Sink ◽  
Volume Ratio ◽  
Heat Sinks ◽  
Liquid Sodium ◽  
Small Scale ◽  
Nusselt Numbers ◽  
The Difference

Abstract 3-D numerical simulations are performed to investigate liquid sodium (Na) flow and the heat transfer within miniature heat sinks with different geometries and hydraulic diameters of less than 5 mm. Two different straight small-scale heat sinks with rectangular and triangular cross-sections are studied in the laminar flow with the Reynolds number up to 1900. The local and average Nusselt numbers are obtained and compared against eachother. At the same surface area to volume ratio, rectangular minichannel heat sink leads to almost 280% higher convective heat transfer rate in comparison with triangular heat sink. It is observed that the difference between thermal efficiencies of rectangular and triangular minichannel heat sinks was independent of flow Reynolds number.

Novel axonal projection from the caudal end of the ventrolateral medulla to the intermediolateral cell column

2007 ◽  
Vol 292 (2) ◽  
pp. R927-R936 ◽  
Author(s):  
Kamon Iigaya ◽  
Hiroo Kumagai ◽  
Hiroshi Onimaru ◽  
Akira Kawai ◽  
Naoki Oshima ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Optical Imaging ◽  
Cross Sections ◽  
Ventral Surface ◽  
Ventrolateral Medulla ◽  
Cell Column ◽  
Spontaneously Hypertensive ◽  
Optical Images ◽  
Caudal Pressor ◽  
Wistar Kyoto

We used an optical imaging technique to investigate whether axons of neurons in the caudal end of the ventrolateral medulla (CeVLM), as well as axons of neurons in the rostral ventrolateral medulla (RVLM), project to neurons in the intermediolateral cell column (IML) of the spinal cord. Brain stem-spinal cord preparations from neonatal normotensive Wistar-Kyoto and spontaneously hypertensive rats were stained with a voltage-sensitive dye, and responses to electrical stimulation of the IML at the Th2 level were detected as changes in fluorescence intensity with an optical imaging apparatus (MiCAM-01). The results were as follows: 1) depolarizing responses to IML stimulation during low-Ca high-Mg superfusion were detected on the ventral surface of the medulla at the level of the CeVLM, as well as at the level of the RVLM, 2) depolarizing responses were also detected on cross sections at the level of the CeVLM, and they had a latency of 24.0 ± 5.5 (SD) ms, 3) antidromic action potentials in response to IML stimulation were demonstrated in the CeVLM neurons where optical images were detected, and 4) glutamate application to the CeVLM increased the frequency of excitatory postsynaptic potentials (EPSPs) and induced depolarization of the IML neurons. The optical imaging findings suggested a novel axonal and functional projection from neurons in the CeVLM to the IML. The increase in EPSPs of the IML neurons in response to glutamate application suggests that the CeVLM participates in the regulation of sympathetic nerve activity and blood pressure and may correspond to the caudal pressor area.

scholarly journals Using snowflake surface-area-to-volume ratio to model and interpret snowfall triple-frequency radar signatures

2017 ◽  
Vol 17 (19) ◽  
pp. 12011-12030 ◽  
Author(s):  
Mathias Gergely ◽  
Steven J. Cooper ◽  
Timothy J. Garrett
Keyword(s):  
Surface Area ◽  
Cross Sections ◽  
Volume Ratio ◽  
High Sensitivity ◽  
Maximum Size ◽  
Strong Impact ◽  
Triple Frequency ◽  
Bounding Volume ◽  
Wide Range ◽  
Radar Signatures

Abstract. The snowflake microstructure determines the microwave scattering properties of individual snowflakes and has a strong impact on snowfall radar signatures. In this study, individual snowflakes are represented by collections of randomly distributed ice spheres where the size and number of the constituent ice spheres are specified by the snowflake mass and surface-area-to-volume ratio (SAV) and the bounding volume of each ice sphere collection is given by the snowflake maximum dimension. Radar backscatter cross sections for the ice sphere collections are calculated at X-, Ku-, Ka-, and W-band frequencies and then used to model triple-frequency radar signatures for exponential snowflake size distributions (SSDs). Additionally, snowflake complexity values obtained from high-resolution multi-view snowflake images are used as an indicator of snowflake SAV to derive snowfall triple-frequency radar signatures. The modeled snowfall triple-frequency radar signatures cover a wide range of triple-frequency signatures that were previously determined from radar reflectivity measurements and illustrate characteristic differences related to snow type, quantified through snowflake SAV, and snowflake size. The results show high sensitivity to snowflake SAV and SSD maximum size but are generally less affected by uncertainties in the parameterization of snowflake mass, indicating the importance of snowflake SAV for the interpretation of snowfall triple-frequency radar signatures.

Bending tests for the structural safety assessment of space truss members

2018 ◽  
Vol 33 (3-4) ◽  
pp. 138-149 ◽  
Author(s):  
Marco Bonopera ◽  
Kuo-Chun Chang ◽  
Chun-Chung Chen ◽  
Tzu-Kang Lin ◽  
Nerio Tullini
Keyword(s):  
Cross Sections ◽  
Flexural Rigidity ◽  
Compressive Force ◽  
Scale Space ◽  
Transverse Load ◽  
Structural Safety ◽  
Small Scale ◽  
Order Effects ◽  
Beam Columns ◽  
Space Truss

This article compares two nondestructive static methods used for the axial load assessment in prismatic beam-columns of space trusses. Examples include the struts and ties or the tension chords and diagonal braces of steel pipe racks or roof trusses. The first method requires knowledge of the beam-column’s flexural rigidity under investigation, whereas the second requires knowledge of the corresponding Euler buckling load. In both procedures, short-term flexural displacements must be measured at the given cross sections along the beam-column under examination and subjected to an additional transverse load. The proposed methods were verified by numerical and laboratory tests on beams of a small-scale space truss prototype made from aluminum alloy and rigid connections. In general, if the higher second-order effects are induced during testing and the corresponding total displacements are accurately measured, it would be easy to obtain tensile and compressive force estimations.

Measurement of fission neutron spectrum averaged cross sections of some threshold reactions on europium: small scale production of no-carrier-added 153Sm in a nuclear reactor

2002 ◽  
Vol 90 (2) ◽  
Author(s):  
I. Fatima ◽  
Jamshed H. Zaidi ◽  
Shujaat Ahmad ◽  
M. S. Subhani
Keyword(s):  
Neutron Spectrum ◽  
Cross Sections ◽  
Nuclear Reactor ◽  
Fission Neutron ◽  
Small Scale ◽  
Activation Technique ◽  
Scale Production ◽  
Radiochemical Separations ◽  
Fission Neutron Spectrum ◽  
Γ Ray

SummaryEmploying the activation technique in combination with radiochemical separations and high-resolution γ-ray spectroscopy fission neutron spectrum averaged cross sections were measured for several (

scholarly journals Influence of Large Relative Tip Clearances for a Micro Radial Fan and Design Guidelines for Increased Efficiency

2020 ◽  
Author(s):  
Patrick H. Wagner ◽  
Jan Van herle ◽  
Lili Gu ◽  
Jürg Schiffmann
Keyword(s):  
Pressure Rise ◽  
Leading Edge ◽  
High Sensitivity ◽  
Design Guidelines ◽  
Tip Clearance ◽  
Small Scale ◽  
Blade Tip ◽  
Dynamics Simulations ◽  
Experimental Findings ◽  
Blade Tip Clearance

Abstract The blade tip clearance loss was studied experimentally and numerically for a micro radial fan with a tip diameter of 19.2mm. Its relative blade tip clearance, i.e., the clearance divided by the blade height of 1.82 mm, was adjusted with different shims. The fan characteristics were experimentally determined for an operation at the nominal rotational speed of 168 krpm with hot air (200 °C). The total-to-total pressure rise and efficiency increased from 49 mbar to 68 mbar and from 53% to 64%, respectively, by reducing the relative tip clearance from 7.7% to the design value of 2.2%. Single and full passage computational fluid dynamics simulations correlate well with these experimental findings. The widely-used Pfleiderer loss correlation with an empirical coefficient of 2.8 fits the numerical simulation and the experiments within +2 efficiency points. The high sensitivity to the tip clearance loss is a result of the design specific speed of 0.80, the highly-backward curved blades (17°), and possibly the low Reynolds number (1 × 105). The authors suggest three main measures to mitigate the blade tip clearance losses for small-scale fans: (1) utilization of high-precision surfaced-grooved gas-bearings to lower the blade tip clearance, (2) a mid-loaded blade design, and (3) an unloaded fan leading edge to reduce the blade tip clearance vortex in the fan passage.

Performance and Reliability of MEMS Gyroscopes and Packaging at High Temperatures

2010 ◽  
Vol 2010 (HITEC) ◽  
pp. 000359-000366 ◽  
Author(s):  
Patrick McCluskey ◽  
Chandradip Patel ◽  
David Lemus
Keyword(s):  
High Temperature ◽  
Indoor Environment ◽  
Elevated Temperatures ◽  
High Sensitivity ◽  
Effect Of Temperature ◽  
Gps Tracking ◽  
Mems Gyroscope ◽  
Mems Gyroscopes ◽  
Gyroscope Sensor

Elevated temperatures can significantly affect the performance and reliability of MEMS gyroscope sensors. A MEMS vibrating resonant gyroscope measures angular velocity via a displacement measurement which can be on the order on nanometers. High sensitivity to small changes in displacement causes the MEMS Gyroscope sensor to be strongly affected by changes in temperature which can affect the displacement of the sensor due to thermal expansion and thermomechanical stresses. Analyzing the effect of temperature on MEMS gyroscope sensor measurements is essential in mission critical high temperature applications, such as inertial tracking of the movement of a fire fighter in a smoke filled indoor environment where GPS tracking is not possible. In this paper, we will discuss the development of the high temperature package for the tracking application, including the characterization of the temperature effects on the performance of a MEMS gyroscope. Both stationary and rotary tests were performed at room and at elevated temperatures on 10 individual single axis MEMS gyroscope sensors.

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