47,580 research outputs found
Rocket engine injector Patent
Rocket engine injector orifice to accommodate changes in density, velocity, and pressure, thereby maintaining constant mass flow rate of propellant into rocket combustion chambe
Injector-valve device Patent
Apparatus for cooling and injecting hypergolic propellants into combustion chamber of small rocket engin
Beyond Disability Civil Rights
[Excerpt] This Article argues that to be effective, both domestic and international disability rights must adopt a disability human rights paradigm. Such a framework combines the type of civil and political rights provided by antidiscrimination legislation (also called negative or first-generation rights) with the full spectrum of social, cultural, and economic measures (also called positive or second-generation rights) bestowed by many human rights treaties.16 By acting holistically, this agenda accounts for factors normally exogenous to civil rights laws and ensures that individuals can flourish and participate in their societies. Accordingly, our intention is to share some thoughts on how to best provide disabled citizens with equal opportunity rather than “merely” equal treatment. Internationally, States and civil society organizations have been developing innovative and effective equality measures. We draw on their experiences in providing examples of how disability legislation and policy can be developed to implement a more holistic human rights approach. These lessons are also pertinent for invigorating the ADA
Performance Analysis for Time-of-Arrival Estimation with Oversampled Low-Complexity 1-bit A/D Conversion
Analog-to-digtial (A/D) conversion plays a crucial role when it comes to the
design of energy-efficient and fast signal processing systems. As its
complexity grows exponentially with the number of output bits, significant
savings are possible when resorting to a minimum resolution of a single bit.
However, then the nonlinear effect which is introduced by the A/D converter
results in a pronounced performance loss, in particular for the case when the
receiver is operated outside the low signal-to-noise ratio (SNR) regime. By
trading the A/D resolution for a moderately faster sampling rate, we show that
for time-of-arrival (TOA) estimation under any SNR level it is possible to
obtain a low-complexity -bit receive system which features a smaller
performance degradation then the classical low SNR hard-limiting loss of
( dB). Key to this result is the employment of a lower bound for
the Fisher information matrix which enables us to approximate the estimation
performance for coarsely quantized receivers with correlated noise models in a
pessimistic way
Asymptotic Signal Detection Rates with 1-bit Array Measurements
This work considers detecting the presence of a band-limited random radio
source using an antenna array featuring a low-complexity digitization process
with single-bit output resolution. In contrast to high-resolution
analog-to-digital conversion, such a direct transformation of the analog radio
measurements to a binary representation can be implemented hardware and
energy-efficient. However, the probabilistic model of the binary receive data
becomes challenging. Therefore, we first consider the Neyman-Pearson test
within generic exponential families and derive the associated analytic
detection rate expressions. Then we use a specific replacement model for the
binary likelihood and study the achievable detection performance with 1- bit
radio array measurements. As an application, we explore the capability of a
low-complexity GPS spectrum monitoring system with different numbers of
antennas and different observation intervals. Results show that with a moderate
amount of binary sensors it is possible to reliably perform the monitoring
task
Performance Analysis for Time-of-Arrival Estimation with Oversampled Low-Complexity 1-bit A/D Conversion
Analog-to-digtial (A/D) conversion plays a crucial role when it comes to the
design of energy-efficient and fast signal processing systems. As its
complexity grows exponentially with the number of output bits, significant
savings are possible when resorting to a minimum resolution of a single bit.
However, then the nonlinear effect which is introduced by the A/D converter
results in a pronounced performance loss, in particular for the case when the
receiver is operated outside the low signal-to-noise ratio (SNR) regime. By
trading the A/D resolution for a moderately faster sampling rate, we show that
for time-of-arrival (TOA) estimation under any SNR level it is possible to
obtain a low-complexity -bit receive system which features a smaller
performance degradation then the classical low SNR hard-limiting loss of
( dB). Key to this result is the employment of a lower bound for
the Fisher information matrix which enables us to approximate the estimation
performance for coarsely quantized receivers with correlated noise models in a
pessimistic way
Rheological control of Wadati-Benioff zone seismicity
Intermediate and deep focus earthquakes in Wadati-Benioff zones are thought to occur in the cold interiors of downgoing slabs which are significantly stronger than the warmer mantle. Given that earthquakes in oceanic lithosphere appear restricted by an isotherm, and hence a given value of lithospheric strength, we investigate whether a similar formulation is useful for subducting plates. Strength in downgoing slabs should be affected by both pressure and temperature, an effect previously treated using a depth‐dependent limiting temperature for seismicity [Wortel, 1982]. We find this limiting temperature implies that a possible limiting strength increases strongly with depth, unless either the temperatures were too low or the activation volume too large. Comparison of the analytic model used by Wortel with numerical thermal models appears to exclude the first possibility. We explore the second possibility by using the numerical thermal model to compute strength contours for flow law constants reported from laboratory experiments, and find that the expected pressure strengthening is large enough that the slab should have considerable strength well below the deepest seismicity. We conclude that if laboratory results are applicable to these conditions, either a strongly depth‐dependent limiting strength exists or factors in addition to strength control the distribution of subduction zone earthquakes
- …