Barrier Layer Impact on Rapid Intensification of Hurricanes (2000-2018) in the Atlantic Ocean

Hurricane prediction is an evolving challenge that has seen much improvement over the years. While hurricane models have improved in predicting the path of storms, forecasts of hurricane intensity are unreliable due to the complexity of environmental data, lack of understanding of how relative humidity, vertical wind shear, hurricane structure and other possible factors affect intensity. Rapid Intensification (RI), which is a wind speed increase of +30 kts over a 24-hr period, can contribute to major destruction and loss of life to coastal communities affected by hurricanes, and is especially difficult to predict. Given the continued development of coastal regions and the threat of RI occurring without warning, it is imperative to better examine all possible factors that might influence hurricane RI to better understand and predict RI. The need for more research into RI was underscored by the devastation caused by rapidly intensifying hurricanes in the Caribbean and the east and gulf coast regions of the U.S. during the 2017 and 2018 hurricane seasons, which included the first landfall of a Category 5 hurricane (Hurricane Michael, 2018) since Hurricane Andrew in 1992. Recent studies examining the barrier layer (BL) of the water column and its relationship to hurricane intensification have shown that BLs favor RI, and that barrier layer thickness (BLT) may influence the storm’s intensity. To determine if BLs might improve the prediction of hurricane intensity, this study examined all hurricanes in the Atlantic Ocean, Caribbean, and Gulf of Mexico spanning the years 2000-2018. Using relevant HYCOM data, daily temperature (T), salinity (S), mixed layer thickness (mlp), isothermal layer thickness (mld), and BLT were examined to determine each factor’s horizontal distribution and possible influence on RI events occurring during the 139 hurricanes. Additional analysis was conducted on 12 randomly selected hurricanes (six of which had RI events and six of which did not) to determine if these factors, specifically BLT, act as significant predictors for RI events. Although no known link has been shown in previous research, this study also sought to determine if there is a correlation between RI and the horizontal variability of BLT and other key factors near the center of a hurricane (within 1 degree lat/lon).Though BLs can exist in any ocean, they are constantly changing and not always present. In this study, however, it was observed that BLs were present during all hurricanes in the Atlantic (2000-2018), whether they experienced a period of RI or not. Using an untested horizontal statistical analysis, this study shows that barrier layer thickness (BLT) does not appear to be a significant predictor of the probability of an RI event to occur, with no clear relationship shown between BLT and the magnitude of intensification, but these results cannot be taken as definitive. Given the limitations of this study, future research on hurricane RI should incorporate all known factors that impact hurricane intensity, testing each using multiple intensity models across all ocean basins

Split-resonator integrated-post MEMS gyroscope

A split-resonator integrated-post vibratory microgyroscope may be fabricated using micro electrical mechanical systems (MEMS) fabrication techniques. The microgyroscope may include two gyroscope sections bonded together, each gyroscope section including resonator petals, electrodes, and an integrated half post. The half posts are aligned and bonded to act as a single post

Development of a coaxial plasma gun for space propulsion final report

Current sheet accelerators and pulsed plasma thrustors for spacecraft propulsio

Integrated low power digital gyro control electronics

Embodiments of the invention generally encompass a digital, application specific integrated circuit (ASIC) has been designed to perform excitation of a selected mode within a vibratory rate gyroscope, damping, or force-rebalance, of other modes within the sensor, and signal demodulation of the in-phase and quadrature components of the signal containing the angular rate information. The ASIC filters dedicated to each channel may be individually programmed to accommodate different rate sensor designs/technology or variations within the same class of sensors. The ASIC architecture employs a low-power design, making the ASIC, particularly suitable for use in power-sensitive applications

Electrostatic spring softening in redundant degree of freedom resonators

The present invention discloses an isolated electrostatic biased resonator gyroscope. The gyroscope includes an isolated resonator having a first and a second differential vibration mode, a baseplate supporting the isolated resonator, a plurality of excitation affixed to the baseplate for exciting the first differential vibration mode, a plurality of sensing electrodes affixed to the baseplate for sensing movement of the gyroscope through the second differential vibration mode and a plurality of bias electrodes affixed to the baseplate for trimming isolation of the resonator and substantially minimizing frequency split between the first and second differential vibration modes. Typically, the isolated resonator comprises a proof mass and a counterbalancing plate with the bias electrodes disposed on the baseplate below

Parametrically disciplined operation of a vibratory gyroscope

Parametrically disciplined operation of a symmetric nearly degenerate mode vibratory gyroscope is disclosed. A parametrically-disciplined inertial wave gyroscope having a natural oscillation frequency in the neighborhood of a sub-harmonic of an external stable clock reference is produced by driving an electrostatic bias electrode at approximately twice this sub-harmonic frequency to achieve disciplined frequency and phase operation of the resonator. A nearly symmetric parametrically-disciplined inertial wave gyroscope that can oscillate in any transverse direction and has more than one bias electrostatic electrode that can be independently driven at twice its oscillation frequency at an amplitude and phase that disciplines its damping to zero in any vibration direction. In addition, operation of a parametrically-disciplined inertial wave gyroscope is taught in which the precession rate of the driven vibration pattern is digitally disciplined to a prescribed non-zero reference value

Method of producing an integral resonator sensor and case

The present invention discloses an inertial sensor having an integral resonator. A typical sensor comprises a planar mechanical resonator for sensing motion of the inertial sensor and a case for housing the resonator. The resonator and a wall of the case are defined through an etching process. A typical method of producing the resonator includes etching a baseplate, bonding a wafer to the etched baseplate, through etching the wafer to form a planar mechanical resonator and the wall of the case and bonding an end cap wafer to the wall to complete the case

Integral resonator gyroscope

The present invention discloses an inertial sensor having an integral resonator. A typical sensor comprises a planar mechanical resonator for sensing motion of the inertial sensor and a case for housing the resonator. The resonator and a wall of the case are defined through an etching process. A typical method of producing the resonator includes etching a baseplate, bonding a wafer to the etched baseplate, through etching the wafer to form a planar mechanical resonator and the wall of the case and bonding an end cap wafer to the wall to complete the case

Contacts between the endoplasmic reticulum and other membranes in neurons

The cytoplasm of eukaryotic cells is compartmentalized by intracellular membranes that define subcellular organelles. One of these organelles, the endoplasmic reticulum, forms a continuous network of tubules and cisternae that extends throughout all cell compartments, including neuronal dendrites and axons. This network communicates with most other organelles by vesicular transport, and also by contacts that do not lead to fusion but allow cross-talk between adjacent bilayers. Though these membrane contacts have previously been observed in neurons, their distribution and abundance has not been systematically analyzed. Here, we have carried out such analysis. Our studies reveal new aspects of the internal structure of neurons and provide a critical complement to information about interorganelle communication emerging from functional and biochemical studies