Radiative transfer in cylindrical threads with incident radiation. VII. Multi-thread models

Aims. Our aim is to improve on previous radiative transfer calculations in illuminated cylindrical threads in order to better understand the physical conditions in cool solar chromospheric and coronal structures commonly observed in hydrogen and helium lines. Methods. We solve the radiative transfer and statistical equilibrium equations in a two-dimensional cross-section of a cylindrical structure oriented horizontally and lying above the solar surface. The cylinder is filled with a mixture of hydrogen and helium, and is illuminated at a given altitude from the solar disc. We construct simple models made from a single thread, or from an ensemble of several threads along the line of sight. This first use of 2D multi-thread fine structure modelling combining hydrogen and helium radiative transfer allows us to compute synthetic emergent spectra from cylindrical structures and to study the effect of line-of-sight integration of an ensemble of threads under a range of physical conditions. We analyse the effects of variations in temperature distribution and in gas pressure.We consider the effect of multi-thread structures within a given field of view and the effect of peculiar velocities between the structures in a multi-thread model. These new models are compared to the single thread model, and tested with varying parameters. Results. The presence of a temperature gradient, with temperature increasing towards the edge of the cylindrical thread, reduces the relative importance of the incident radiation coming from the solar disc on the emergent intensities of most hydrogen and helium lines. We also find that when assuming randomly displaced threads in a given field of view, the integrated intensities of optically thick and thin transitions behave considerably differently. In optically thin lines, the emergent intensity increases proportionally with the number of threads, and the spatial variation of the intensity becomes increasingly homogeneous. Optically thick lines however saturate after only a few threads. As a consequence, the spatial variation of the intensity retains much similarity with that of the first few threads. The multi-thread model produces complex line profiles with significant asymmetries if randomly generated line-of-sight velocities are added for each thread. Conclusions. These new computations show for the first time the effect of integrating the radiation emitted in H and He lines by several cylindrical threads static or moving along the line of sight. They can be used to interpret high-spatial and spectral resolutions of cylindrical structures found in the solar atmosphere, such as cool coronal loops or prominence threads

Variable Sweep Transition Flight Experiment (VSTFE): Unified Stability System (USS). Description and Users' Manual

NASA initiated the Variable Sweep Transition Flight Experiment (VSTFE) to establish a boundary layer transition database for laminar flow wing design. For this experiment, full-span upper surface gloves were fitted to a variable sweep F-14 aircraft. The development of an improved laminar boundary layer stability analysis system called the Unified Stability System (USS) is documented and results of its use on the VSTFE flight data are shown. The USS consists of eight computer codes. The theoretical background of the system is described, as is the input, output, and usage hints. The USS is capable of analyzing boundary layer stability over a wide range of disturbance frequencies and orientations, making it possible to use different philosophies in calculating the growth of disturbances on sweptwings

Melody based tune retrieval over the World Wide Web

In this paper we describe the steps taken to develop a Web-based version of an existing stand-alone, single-user digital library application for melodical searching of a collection of music. For the three key components: input, searching, and output, we assess the suitability of various Web-based strategies that deal with the now distributed software architecture and explain the decisions we made. The resulting melody indexing service, known as MELDEX, has been in operation for one year, and the feed-back we have received has been favorable

Dimensions of Grace: Factor Analysis of Three Grace Scales

Measuring grace is challenging. Prior research found the Grace Scale (GS), Richmont Grace Scale (RGS), and The Amazing Grace Scale (TAGS) to be reliable, have promising convergent and divergent validity, and to inter-correlate strongly. However, they may tap different constructs, or grace may be multidimensional (Bufford, Blackburn, Sisemore, & Bassett, 2015). Here two exploratory factor analyses of the combined items showed five factors: experiencing God’s grace, costly grace, grace to self, grace from others, and grace to others, partially paralleling Watson, Chen and Sisemore (2011). Items from all three scales loaded on Factor 1, only items from the RGS loaded on Factor 2. The remaining factors were mostly GS items and a few RGS items. The three scales measure somewhat different constructs. Preliminary validity for the five factors is promising. Regressions showed that combinations of the other four proposed scales accounted for at most about one third of the variance on any given grace factor. The five factors showed different patterns of relationships to criterion variables. We propose a 36 item Dimensions of Grace Scale combining items from all three scales for further exploration

Tracking Lone Wolf Terrorists

Terrorism takes many forms, and many advances in identifying and tracking terrorists have been made in the past few years. However, the rise of self-radicalized lone wolf terrorists is an increasing challenge, compounded by their different types and the social and political contexts in which their threats exist. These predators require multiple strategies to track and neutralize

The Sociological Perspective Revisited

The Sociological Perspective Revisited Dr. Rodger Bates In the 1950s, sociology was committed to the development of a set of basic concepts for advancing the discipline. Heavily influenced by structure-functionalism, sociology focused on general and mid-range theories in seeking to understand and explain society. By the 1960s this perspective was challenged by the emergence of modern conflict theory with its emphases on race, class and gender and the consequences of inequality. However, with the success of the social movements of the latter half of the century, sociology embraced deconstructionism. As a consequence of this trend, sociology increasingly embraced empathy and personal experience over systemic understanding and scientific inquiry. Today, the relevance of sociology as a tool of understanding is being challenged by the sociology of me. “The Sociological Perspective Revisited” describes this transformation and the challenges it creates for the future of the discipline