نتایج جستجو برای: roll
تعداد نتایج: 13694 فیلتر نتایج به سال:
The standard calculation of the spectrum of density perturbations produced during inflation assumes (i) |n − 1| ≪ 1 and (ii) |dn/d ln k| ≪ |n − 1|. Slow-roll predicts and observations require (i), but neither slow-roll nor observations require (ii). In this paper I derive formulae for the spectrum P, spectral index n, and running of the spectral index dn/d ln k, assuming only (i) and not (ii). ...
Observations during the Convection and Precipitation/Electrification (CaPE) project illustrate that horizontal convective rolls are capable of providing sufficient forcing to initiate free moist convection. Rolls occurred on the majority of days during CaPE but on only some of those days were they able to trigger thunderstorms. This study was undertaken to ascertain the difference between the t...
In this paper, an aircraft roll control system for an autopilot that controls the roll angle motion of an aircraft is modeled and simulated using MATLAB/ Simulink. As the roll angle motion is a lateral directional motion, the mathematical model is derived [1]. The control system considered for this roll angle control is PID controller. In this work the PID controller for the roll transfer funct...
Shallow-water equations with bottom drag and viscosity are used to study the dynamics of roll waves. First, we explore the effect of bottom topography on linear stability of turbulent flow over uneven surfaces. Low-amplitude topography is found to destabilize turbulent roll waves and lower the critical Froude number required for instability. At higher amplitude, the trend reverses and topograph...
BACKGROUND/AIM Breast lesions that are not palpable on physical examination but considered suspicious for malignancy on mammography or ultrasonography should be marked before surgery. Wire-guided localization (WGL) is the most frequently used method for preoperative marking of nonpalpable breast lesions (NPBLs). An alternative is marking by a radioactive agent (radio-guided occult lesion locali...
ROCK & ROLL is a deductive object-oriented database system that supports two languages, one imperative and the other deductive, both derived from the same object-oriented data model. As the languages share a common type system, they can be integrated without manifesting impedance mismatches, and thus programmers can conveniently exploit both deductive and imperative features in a single applica...
Effect of antenna polarization on the capacity of a multiple element system in an indoor environment
In this paper, we analyze the behavior of a multiple element antenna system in an indoor environment based on the measurements taken in the Lucent Bell Labs building in Crawford Hill, NJ, with a system of 12 transmitters and 15 receivers. In particular, we investigate the capacity behavior with respect to the polarization of the transmitting/receiving elements and the distance between the trans...
Channel assignment strategies for use with a high altitude platform, spot beam architecture are examined. A novel power roll-off approximation is derived to allow terrestrial simulation tools to be used, and simulation performance is compared with a theoretical lower bound derived from the Engset distribution. It is shown that the use of cell overlap considerably enhances the blocking probabili...
Observers misperceive the orientation of a vertical rod when it is viewed in the context of a tilted frame (the rod and frame illusion, or RFI). The pitch and roll of the surrounding surfaces have independent influences on this illusion (Nelson and Prinzmetal, 2003). Experiment 1 measured the RFI when the pitch and roll of the floor that supported the observer was varied, and the observer was e...
The roll forming industry has many difficulties in product development and process set-up. The design and development of rolls and processes re mainly based on trial-and-error and past experiences. Recent industrial trends demand products having high quality and tight tolerances. This equires more precise and cost-effective roll-forming processes than the ones employed in the traditional produc...
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