Two-dimensional, supersonic mixing of hydrogen and air near a wall

Two dimensional, supersonic mixing of hydrogen injected from wall slot into airstrea

Look before you leap: a confidence-based method for selecting species criticality while avoiding negative populations in τ\tau-leaping

The stochastic simulation algorithm was introduced by Gillespie and in a different form by Kurtz. There have been many attempts at accelerating the algorithm without deviating from the behavior of the simulated system. The crux of the explicit $\tau$-leaping procedure is the use of Poisson random variables to approximate the number of occurrences of each type of reaction event during a carefully selected time period, $\tau$. This method is acceptable providing the leap condition, that no propensity function changes “significantly” during any time-step, is met. Using this method there is a possibility that species numbers can, artificially, become negative. Several recent papers have demonstrated methods that avoid this situation. One such method classifies, as critical, those reactions in danger of sending species populations negative. At most, one of these critical reactions is allowed to occur in the next time-step. We argue that the criticality of a reactant species and its dependent reaction channels should be related to the probability of the species number becoming negative. This way only reactions that, if fired, produce a high probability of driving a reactant population negative are labeled critical. The number of firings of more reaction channels can be approximated using Poisson random variables thus speeding up the simulation while maintaining the accuracy. In implementing this revised method of criticality selection we make use of the probability distribution from which the random variable describing the change in species number is drawn. We give several numerical examples to demonstrate the effectiveness of our new metho

Research rocket test RR-1 (Black Brant VC) and RR-2 (Aerobee 170A): Investigations of the stability of bubbles in plain and fiber-reinforced metal and solidified in a near-zero-g environment

The results of the first two of a series of research rocket flights are presented. The objectives of these flights were (1) to learn about the capabilities of these rockets, (2) to learn how to interface the payloads and rockets, and (3) to process some of the composite casting demonstration capsules intended originally for Apollo 15. The capsules contained experiments for investigating the stability of gas bubbles in plain and fiber-reinforced metal melted and solidified in a near-zero-g (0.0119g) environment. The characteristics of the two research rockets, an Aerobee 170A and a Black Brant VC, used to obtain the periods of near-zero-g and the temperature control unit used for processing the contents of the two experiment capsules are discussed

Geometry requirements for unsteady aerodynamics in aeroelastic analysis and design

Aircraft geometry requirements for unsteady aerodynamic computations are discussed and differences between requirements for steady and unsteady flow are emphasized within the framework of a general potential-flow aerodynamic formulation. Its implementation in a computer program called SOUSSA (Steady, Oscillatory, and Unsteady Subsonic and Supersonic Aerodynamic is detailed

From microscopic to macroscopic descriptions of cell\ud migration on growing domains

Cell migration and growth are essential components of the development of multicellular organisms. The role of various cues in directing cell migration is widespread, in particular, the role of signals in the environment in the control of cell motility and directional guidance. In many cases, especially in developmental biology, growth of the domain also plays a large role in the distribution of cells and, in some cases, cell or signal distribution may actually drive domain growth. There is a ubiquitous use of partial differential equations (PDEs) for modelling the time evolution of cellular density and environmental cues. In the last twenty years, a lot of attention has been devoted to connecting macroscopic PDEs with more detailed microscopic models of cellular motility, including models of directional sensing and signal transduction pathways. However, domain growth is largely omitted in the literature. In this paper, individual-based models describing cell movement and domain growth are studied, and correspondence with a macroscopic-level PDE describing the evolution of cell density is demonstrated. The individual-based models are formulated in terms of random walkers on a lattice. Domain growth provides an extra mathematical challenge by making the lattice size variable over time. A reaction-diffusion master equation formalism is generalised to the case of growing lattices and used in the derivation of the macroscopic PDEs

The M. W. Burks Site (41WD52): A Late Caddo Hamlet in Wood County, Texas

While attempting to locate and evaluate prehistoric Caddo archaeological sites in the Dry Creek watershed, Wood County, Texas, that had been originally recorded by A. T. Jackson and M. M. Reese in 1930, the M. W. Burks site (41WD52) was discovered by James E. Bruseth and Bob D. Skiles in June 1977. The site is in the Forest Hill community, about 5 km north of Quitman, Texas, in the East Texas Pineywoods and Gulf Coastal Plain. It is on a small rise in the uplands overlooking a small intermittent drainage that is an unnamed tributary of Little Dry Creek. The landowner, Mr. M. W. Burks, had resided in this part of Wood County since the 1920s, and recalled where A. T. Jackson and crew had spent time excavating the J. H. Reese (41WD2) site. He mentioned that while putting in a fence on his property in the early 1960s, adjacent to the property where the Reese site is located, he had found some pottery sherds in one of the post holes. Bruseth and Skiles placed a small shovel test next to this fence post hole, and a large articulated red-slipped Ripley Engraved carinated bowl was encountered at 65 em below the surface (bs) in tan sand E-horizon deposits. This find demonstrated that the Burks site contained both intact archaeological deposits as well as an apparently undisturbed Late Caddo Titus phase burial or cemetery. Bruseth, Skiles, and Perttula followed up this work with more intensive investigations in the spring and fall of 1978. This research was carried on as an adjunct to the ongoing (and final season of) archaeological work being conducted by Bruseth and Perttula at Lake Fork Reservoir on Lake Fork Creek, a few miles to the west of the Burks site. Our purpose in carrying out archaeological research at the Burks site was to examine in more detail the spatial character of a Late Caddo Titus phase settlement, and also obtain information on the material culture remains (especially the ceramics) made and used by the Caddo peoples that lived at the Burks site some 400-500 years ago

The Carlisle Site (41WD46), a Middle Caddoan Occupation on the Sabine River, Wood County, Texas

The Carlisle site (41WD46) is located on the Sabine River near its confluence with Lake Fork Creek in the Upper Sabine River Basin. As defined by Perttula, the Upper Sabine River Basin includes the area from the headwaters of the Sabine River to the mouths of Cherokee Bayou and Hatley Creek at the western edge of the Sabine Uplift. Lake Fork Creek is one of several large south-southeastward flowing streams within the Upper Sabine River Basin. The town of Mineola is approximately 13 kilometers (km) west of the Carlisle site. The site is situated at the tip of an upland projection overlooking the Sabine River floodplain, but extends into the floodplain to within ca 30 meters of the river bank. The Lake Fork Creek channel is approximately one km east of the site. While the site was an improved pasture for many years prior to 1975 and to the present, it had been previously cultivated. In fact, this cultivation may have contributed to its initial identification in the early 1930s, as well as its subsequent partial burial. The upland sandy soils derive from the Queen City Formation, and these are highly susceptible to erosion and colluvial downwasting. Colluvial deposition seems to have been a prominent factor in the burial of cultural materials along valley margins and lower footslopes elsewhere in the Upper Sabine Basin, and the site\u27s topographic position suggests that both alluvial and colluvial deposition is responsible for the burial of the floodplain cultural deposits at the Carlisle site

Developments in steady and unsteady aerodynamics for use in aeroelastic analysis and design

A review is given of seven research projects which are aimed at improving the generality, accuracy, and computational efficiency of steady and unsteady aerodynamic theory for use in aeroelastic analysis and design. These projects indicate three major thrusts of current research efforts: (1) more realistic representation of steady and unsteady subsonic and supersonic loads on aircraft configurations of general shape with emphasis on structural-design applications, (2) unsteady aerodynamics for application in active-controls analyses, and (3) unsteady aerodynamics for the frequently critical transonic speed range. The review of each project includes theoretical background, description of capabilities, results of application, current status, and plans for further development and use

The Panel in Context: An Introduction to The Talented Mr. Ripley

This introduction provides a context for the transcript of the panel discussion on The Faction’s production of The Talented Mr. Ripley that took place at London’s New Diorama Theatre in February 2015.1 The event was organized jointly by The Faction and Caroline Bainbridge and Candida Yates, Directors of the Media and Inner World research network. The network was first set up and funded by the AHRC in 2009 with the aim to create a dialogue between academics, media practitioners and creative and psychoanalysts and psychotherapists to explore the role of emotion and unconscious processes in the spheres of both practice and representation within media and culture. Caroline Bainbridge and I have worked with The Faction on a number of occasions, and, in the case of The Talented Mr. Ripley, we also worked with the cast in rehearsals as consultants. This involved focusing on the psychoanalytic themes of the text whilst also using a process consultancy method to explore the relational and affective themes that emerged within rehearsals themselves