Separated flow

A brief overview of flow separation phenomena is provided. Langley has many active research programs in flow separation related areas. Three cases are presented which describe specific examples of flow separation research. In each example, a description of the fundamental fluid physics and the complexity of the flow field is presented along with a method of either reducing or controlling the extent of separation. The following examples are discussed: flow over a smooth surface with an adverse pressure gradient; flow over a surface with a geometric discontinuity; and flow with shock-boundary layer interactions. These results will show that improvements are being made in the understanding of flow separation and its control

Banking from Leeds, not London: regional strategy and structure at the Yorkshire Bank, 1859–1952

Industrial philanthropist Edward Akroyd created the Yorkshire Penny Savings Bank in 1859. Despite competition from the Post Office Savings Bank after 1861 and a serious reserve problem in 1911, it sustained his overall strategy to become a successful regional bank. Using archival and contemporary sources to build on recent scholarship illustrating how savings banks were integrated into local economies and the complementary roles of philanthropy and paternalism, we analyse an English regional bank's strategy, including an assessment of strategic innovation, ownership changes and management structure. This will demonstrate that the founder's vision continued, even though the 1911 crisis radically altered both strategy and structure

Increases in body weight and nutritional status of transplanted Alaskan caribou

Body weight and natality rate in ungulates can be useful indices to nutririon, bur they may also be influenced by genetic and climatic factors. Because caribou {Rangifer tarandus granti) are distributed as discrete populations of metapopulations (i.e., herds) that are usually reproductively isolated from each other for unknown periods, it is difficult to separate the influence of genetics and nutrition on body weight, especially where historical data are lacking. To help elucidate the influence of nutrition on potential variation in body weight and natality of caribou in Alaska, we reviewed data for body weight and natality in 5 populations which resulted from Transplants to previously ungrazed ranges, or to areas where reindeer and caribou had been absent for many decades. In 2 of 5 populations body weight increased significantly, and likely increased in the other 3 populations, but data were insufficient. Natality rate increased in all 5 populations, proportion of fecund yearlings was high and 3 of the 5 newly established herds increased at about the maximum biological potential for the species (lambda=1.35). In the Adak transplant, a lactating yearling was documented. These 5 transplanted populations provide additional evidence that body weight and natality rate in Alaskan caribou are sensitive to changes in population density and relatively short-term (i.e., 10 years) increases in grazing pressure independenr of climate and genetics

Bistable molecular conductors with a field-switchable dipole group

A class of bistable "stator-rotor" molecules is proposed, where a stationary bridge (stator) connects the two electrodes and facilitates electron transport between them. The rotor part, which has a large dipole moment, is attached to an atom of the stator via a single sigma bond. Hydrogen bonds formed between the rotor and stator make the symmetric orientation of the dipole unstable. The rotor has two potential minima with equal energy for rotation about the sigma bond. The dipole orientation, which determines the conduction state of the molecule, can be switched by an external electric field that changes the relative energy of the two potential minima. Both orientation of the rotor correspond to asymmetric current-voltage characteristics that are the reverse of each other, so they are distinguishable electrically. Such bistable stator-rotor molecules could potentially be used as parts of molecular electronic devices.Comment: 8 pages, 7 figure

Performance and Carcass Traits of Market Beef Cattle Supplemented Self-Fed Byproducts on Pasture: Final Report

Over a two year period (2007 and 2008), 162 head of beef steers were finished with self-fed byproducts on cool season grass pastures. Yearling steers were continuously grazed at the Neely-Kinyon Farm in southwest Iowa on cool season grasses that were predominantly fescue at a stocking density of 2.25 head/acre. Half of the cattle were implanted (with Synovex®-S) or half were not. Cattle received a diet of either soyhulls-dried distillers grain with solubles (DDGS) or ground corn-dried distillers grains with solubles that was offered through self-feeders. The rations were mixed at a 1:1 ratio with a mineral balancer added which included Rumensin®. Live cattle performance and carcass traits were not affected by diet. Implanted cattle outgained non-implanted over the entire finishing period (3.52 lbs/d vs. 3.17 lbs/d). This led to implanted cattle coming off test heavier (1324 lbs vs. 1277 lbs) and railing with heavier carcasses (826 lbs vs. 800 lbs). Ribeye areas were greater (13.1 in2 vs. 12.7 in2) for implanted cattle; which was probably due to the heavier carcass weights. Non-implanted cattle had superior quality grades (55% vs. 40%) of low choice or better. Fatty acid profiles from the first year were analyzed and showed that raw beef samples from cattle on the soyhulls diet had significantly higher C18:2 In conclusion, pasture rearing cattle, when given access to self-fed by-products, provides for excellent performance on both live performance and carcass traits. Some considerations should be made by the feeder in regards to time of year when marketing cattle and the cattle’s genetics. This system is an alternative to high-grain conventional beef finishing production in feedlots

Performance and Carcass Traits of Market Beef Cattle Supplemented Self-Fed Byproducts on Pasture: A Progress Report

Over a two year period (2007 and 2008), 162 head of beef steers were finished with self-fed byproducts on cool season grass pastures. Yearling steers were continuously grazed at the Neely-Kinyon Farm in southwest Iowa on cool season grasses that were predominantly fescue at a stocking density of 2.25 head/acre. Half of the cattle were implanted (with Synovex®-S) or and half were not. Cattle received a diet of either soyhulls-dried distillers grain with solubles or corn-dried distillers grains with solubles (DDGS) that was offered as a meal through self-feeders. The rations were mixed in at 1:1 with a mineral balancer that included Rumensin®. Live cattle performance and carcass traits were not affected by diet. Implanted cattle outgained non-implanted over the entire finishing period (3.52 lbs/d vs. 3.17 lbs/d). This led to implanted cattle coming off test heavier (1324 lbs vs. 1277 lbs) and railing with heavier carcasses (826 lbs vs. 800 lbs). Ribeye areas were greater (13.1 in 2 vs. 12.7 in 2 ) for implanted cattle; which was probably due to the heavier carcass weights. Non-implanted cattle had superior quality grades (55% vs. 40%) of low choice or better. Year differences in quality grade (1023 vs. 985 in 2007 and 2008, respectively) were observed. This difference was attributed to factors that include genetic makeup of cattle, initial weights of cattle, time of year when cattle were harvested and grading technology. In conclusion, pasture rearing cattle, when given access to self-fed by-products, provides for excellent performance on both live performance and carcass traits. Some considerations should be made by the feeder in regards to time of year when marketing cattle and the cattle’s genetics. This system is an alternative to high-grain conventional beef finishing production in feedlots

Mutation-aware fault prediction

We introduce mutation-aware fault prediction, which leverages additional guidance from metrics constructed in terms of mutants and the test cases that cover and detect them. We report the results of 12 sets of experiments, applying 4 di↵erent predictive modelling techniques to 3 large real world systems (both open and closed source). The results show that our proposal can significantly (p 0.05) improve fault prediction performance. Moreover, mutation based metrics lie in the top 5% most frequently relied upon fault predictors in 10 of the 12 sets of experiments, and provide the majority of the top ten fault predictors in 9 of the 12 sets of experiments.http://www0.cs.ucl.ac.uk/staff/F.Sarro/resource/papers/ISSTA2016-Bowesetal.pd

Multibody dynamics analysis (MDA) as a numerical modelling tool to reconstruct the function and palaeobiology of extinct organisms

Recent advances in computer technology have substantially changed the field of palaeontology in the last two decades. Palaeontologists now have a whole new arsenal of powerful digital techniques available to study fossil organisms in unprecedented detail and to test hypotheses regarding function and behaviour. Multibody dynamics analysis (MDA) is one of these techniques and although it originated as a tool used in the engineering and automotive industry, it holds great potential to address palaeontological questions as well. MDA allows the simulation of dynamic movements in complex objects consisting of multiple linked components. As such, this technique is ideally suited to model biological structures and to obtain quantifiable results that can be used to test the function of musculoskeletal systems rigorously. However, despite these advantages, MDA has seen a slow uptake by the palaeontological community. The most likely reason for this lies in the steep learning curve and complexity of the method. This paper provides an overview of the underlying principles of MDA and outlines the main steps involved in conducting analyses. A number of recent studies using MDA to reconstruct the palaeobiology of fossil organisms are presented and the potential for future studies is discussed. Similar to other computational techniques, including finite element analysis and computational fluid dynamics, the non‐invasive and exploratory power of MDA makes it ideally suited to study the form and function in vertebrates for which no modern analogues exist

Vulnerability to xylem cavitation and the distribution of sonoran desert vegetation

Journal ArticleWe studied 15 riparian and upland Sonoran desert species to evaluate how the limitation of xylem pressure (Vx) by cavitation corresponded with plant distribution along a moisture gradient. Riparian species were obligate riparian trees (Fraxinus velutina, Populus fremontii, and Salix gooddingii), native shrubs (Baccharis spp.), and an exotic shrub (Tamarix ramosissima). Upland species were evergreen (Juniperus monosperma, Larrea tridentata), drought-deciduous (Ambrosia dumosa, Encelia farinosa, Fouquieria splendens, Cercidium microphyllum), and winter-deciduous (Acacia spp., Prosopis velutina) trees and shrubs