Practical Implementation of a General Numerical Lifting-Line Method

A general numerical lifting-line method provides corrections to overcome the singularities inherent in the lifting-line downwash integrals in certain cases. These singularities have previously limited the scope of lifting-line theory to straight wings not in sideslip; in all other cases, more traditional numerical approaches to solving Prandtl\u27s hypothesis fail to grid converge. However, this general numerical lifting-line method grid converges even for swept wings and wings in sideslip. In the current work, we apply the general numerical lifting-line method to any number of wings with arbitrary geometry. We also provide a dimensional derivation of the basic general numerical lifting-line equations and discuss how airfoil section properties can be corrected for sweep. We develop a linearized system of equations and a nonlinear improvement method to solve the general numerical lifting-line equations. Results show that placing the lifting-line on the wing locus of aerodynamic centers, as done by others, may not yield the most accurate results. Comparisons with published data reveal that the general numerical lifting-line method can accurately predict the lift distribution for swept wings

Forward modeling of standing kink modes in coronal loops. I. Synthetic views

Kink magnetohydrodynamic (MHD) waves are frequently observed in various magnetic structures of the solar atmosphere. They may contribute significantly to coronal heating and could be used as a tool to diagnose the solar plasma. In this study, we synthesize the Fe ix λ171.073 emission of a coronal loop supporting a standing kink MHD mode. The kink MHD wave solution of a plasma cylinder is mapped into a semi-torus structure to simulate a curved coronal loop. We decompose the solution into a quasi-rigid kink motion and a quadrupole term, which dominate the plasma inside and outside of the flux tube, respectively. At the loop edges, the line of sight integrates relatively more ambient plasma, and the background emission becomes significant. The plasma motion associated with the quadrupole term causes spectral line broadening and emission suppression. The periodic intensity suppression will modulate the integrated intensity and the effective loop width, which both exhibit oscillatory variations at half of the kink period. The quadrupole term can be directly observed as a pendular motion at the front view

Three-Wall Segment (TriSeg) Model Describing Mechanics and Hemodynamics of Ventricular Interaction

A mathematical model (TriSeg model) of ventricular mechanics incorporating mechanical interaction of the left and right ventricular free walls and the interventricular septum is presented. Global left and right ventricular pump mechanics were related to representative myofiber mechanics in the three ventricular walls, satisfying the principle of conservation of energy. The walls were mechanically coupled satisfying tensile force equilibrium in the junction. Wall sizes and masses were rendered by adaptation to normalize mechanical myofiber load to physiological standard levels. The TriSeg model was implemented in the previously published lumped closed-loop CircAdapt model of heart and circulation. Simulation results of cardiac mechanics and hemodynamics during normal ventricular loading, acute pulmonary hypertension, and chronic pulmonary hypertension (including load adaptation) agreed with clinical data as obtained in healthy volunteers and pulmonary hypertension patients. In chronic pulmonary hypertension, the model predicted right ventricular free wall hypertrophy, increased systolic pulmonary flow acceleration, and increased right ventricular isovolumic contraction and relaxation times. Furthermore, septal curvature decreased linearly with its transmural pressure difference. In conclusion, the TriSeg model enables realistic simulation of ventricular mechanics including interaction between left and right ventricular pump mechanics, dynamics of septal geometry, and myofiber mechanics in the three ventricular walls

Solar Coronal Plumes

Polar plumes are thin long ray-like structures that project beyond the limb of the Sun polar regions, maintaining their identity over distances of several solar radii. Plumes have been first observed in white-light (WL) images of the Sun, but, with the advent of the space era, they have been identified also in X-ray and UV wavelengths (XUV) and, possibly, even in in situ data. This review traces the history of plumes, from the time they have been first imaged, to the complex means by which nowadays we attempt to reconstruct their 3-D structure. Spectroscopic techniques allowed us also to infer the physical parameters of plumes and estimate their electron and kinetic temperatures and their densities. However, perhaps the most interesting problem we need to solve is the role they cover in the solar wind origin and acceleration: Does the solar wind emanate from plumes or from the ambient coronal hole wherein they are embedded? Do plumes have a role in solar wind acceleration and mass loading? Answers to these questions are still somewhat ambiguous and theoretical modeling does not provide definite answers either. Recent data, with an unprecedented high spatial and temporal resolution, provide new information on the fine structure of plumes, their temporal evolution and relationship with other transient phenomena that may shed further light on these elusive features

Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) Engineering Demonstation Unit (EDU) Overview and Performance Summary

The Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS), developed for the NASA New Millennium Program (NMP) Earth Observing-3 (EO-3) mission, has recently completed a series of uplooking atmospheric measurements. The GIFTS development demonstrates a series of new sensor and data processing technologies that can significantly expand geostationary meteorological observational capability. The resulting increase in forecasting accuracy and atmospheric model development utilizing this hyperspectral data is demonstrated by the uplooking data. The GIFTS sensor is an imaging FTS with programmable spectral resolution and spatial scene selection, allowing spectral resolution and area coverage to be traded in near-real time. Due to funding limitations, the GIFTS sensor module was completed as an engineering demonstration unit that can be upgraded to flight quality. This paper reviews the GIFTS system design considerations and the technology utilized to enable a nearly two order performance increase over the existing GOES sounder and shows its capability. While not designed as an operational sensor, GIFTS EDU provides a flexible and accurate testbed for the new products the hyperspectral era will bring. Efforts to find funding to upgrade and demonstrate this amazing sensor in space are continuing

The effect of stimulus discriminability on the mere exposure effect: Why more variability in the design of cigarette health warnings is needed.

The mere exposure effect refers to the observation that repeated, unreinforced exposure to a stimulus increases affective evaluations of that stimulus. An abundance of previous mere exposure research has utilised neutral, meaningless stimuli, with few studies using emotional stimuli. However, it is highly plausible that the stimuli used in these studies were not truly emotional. Therefore, the aim of this study was to examine the effect of repeated exposure on liking ratings of images which had inherent emotional properties, namely valence and arousal. Three experiments took place. Experiment 1 used neutral yet meaningful images to obtain a baseline but surprisingly, no significant mere exposure effect was found. Experiment 2 then used images differing in valence and arousal in which a significant effect was found for the negative high arousal images only. Guided by these findings, Experiment 3 then used negative high arousal images that have greater societal application, namely cigarette health warning images. Strikingly, a significant mere exposure effect was again found. It is argued that stimulus discriminability played a vital role in the occurrence of the mere exposure effect, such that a significant effect was found only when the stimuli were of similar content to one another. Recommendations were made that the design of cigarette health warnings need to have more variability in the content that is depicted to prevent increases in affective evaluations from occurring