Improved torch increases weld quality in refractory metals

Specially designed torch welds refractory metals in a vacuum purged, inert gas backfilled welding chamber /weld box/ with practically zero contamination resulting from its use. Included in the torch design is a radiation shield to protect the operators hands when welding at high amperages

Mixed nonderivative algorithms for unconstrained optimization

A general technique is developed to restart nonderivative algorithms in unconstrained optimization. Application of the technique is shown to result in mixed algorithms which are considerably more robust than their component procedures. A general mixed algorithm is developed and its convergence is demonstrated. A uniform computational comparison is given for the new mixed algorithms and for a collection of procedures from the literature --Abstract, page ii

Rope ladder routing: position-based multipath routing for wireless mesh networks

Proceedings of: 2010 IEEE International Symposium on "A World of Wireless, Mobile and Multimedia Networks" (WoWMoM), 14-17 June 2010, Montreal, CanadaIn this paper, we present a novel multipath structure called rope-ladder which combines the advantages of path, node and link protection schemes. We also propose a position-based multipath routing protocol in order to efficiently construct rope-ladders in wireless networks. By design, the paths which are constructed by our protocol are closely together which allows to quickly switch back and forth between them in cases of node or link failures. Hence, the size of loss gaps (i.e. the number of consecutively lost packets) can be minimized. Previous works mostly confine themselves to overall packet loss comparisons. However, the loss gap size is crucial to ensure high quality for gap-sensitive traffic like voice flows. Our multipath structure can also tolerate failures of multiple consecutive nodes on the primary path, and has a superior path diversity and path lifetime compared to even perfect braids. We evaluate the performance of our protocol using analysis and simulations.European Community's Seventh Framework ProgramPublicad

ADAPTING LEAST-SQUARE SUPPORT VECTOR REGRESSION MODELS TO FORECAST THE OUTCOME OF HORSERACES

This paper introduces an improved approach for forecasting the outcome of horseraces. Building upon previous literature, a state-of-the-art modelling paradigm is developed which integrates least-square support vector regression and conditional logit procedures to predict horses’ winning probabilities. In order to adapt the least-square support vector regression model to this task, some free parameters have to be determined within a model selection step. Traditionally, this is accomplished by assessing candidate settings in terms of mean-squared error between estimated and actual finishing positions. This paper proposes an augmented approach to organise model selection for horserace forecasting using the concept of ranking borrowed from internet search engine evaluation. In particular, it is shown that the performance of forecasting models can be improved significantly if parameter settings are chosen on the basis of their normalised discounted cumulative gain (i.e. their ability to accurately rank the first few finishers of a race), rather than according to general purpose performance indicators which weight the ability to predict the rank order finish position of all horses equally

Protecting biodiversity and economic returns in resource rich tropical forests

In pursuit of socioeconomic development, many countries are expanding oil and mineral extraction into tropical forests. These activities seed access to remote, biologically rich areas, thereby endangering global biodiversity. Here we demonstrate that conservation solutions that effectively balance the protection of biodiversity and economic revenues are possible in biologically valuable regions. Using spatial data on oil profits and predicted species and ecosystem extents, we optimise the protection of 741 terrestrial species and 20 ecosystems of the Ecuadorian Amazon, across a range of opportunity costs (i.e. sacrifices of extractive profit). For such an optimisation, giving up 5% of a year's oil profits (US$221 million) allows for a protected area network that retains of an average of 65$ 1.7 billion), and uses only marginally less land, to achieve equivalent levels of ecological protection. Applying spatial statistics to remotely sensed, historic deforestation data, we further focus the optimisation to areas most threatened by imminent forest loss. We identify Emergency Conservation Targets: areas that are essential to a cost‐effective conservation reserve network and at imminent risk of destruction, thus requiring urgent and effective protection. Governments should employ the methods presented here when considering extractive led development options, to responsibly manage the associated ecological‐economic trade‐offs and protect natural capital

Cost-efficient wireless mobile backhaul topologies: an analytical study

Proceedings of: 2010 IEEE Global Telecommunications Conference (GLOBECOM 2010), 6-10 December 2010, Miami, Florida, USAWireless communication technologies such as microwave radios are used to provide high-speed mobile backhaul connectivity for radio access networks in cases in which wirebased alternatives, e.g. cable or fiber, are not readily available and cannot be deployed in an economic or timely manner. Current mobile backhauls are predominantly deployed in tree or ring topologies, which simplify traffic management. Yet, with the increasing demand on backhaul capacity and the immense cost pressure on mobile backhaul solutions, meshed wireless mobile backhauls have been identified as a promising evolution. While traffic management in wireless mesh networks have been studied extensively in the literature, so far there is no quantitative analysis comparing the different topology options, i.e. mesh, ring and tree, regarding network performance and deployment cost. This paper fills this gap by studying the minimum cost problem of connecting a set of base station/gateway sites using different topologies while supporting both time- and space-varying traffic demands. Furthermore, we consider the additional constraint of resilience to single link failures. The evaluation results show that meshed wireless backhaul topologies are a cost-effective alternative to trees and rings, in particular in the face of spatial and temporal fluctuation of traffic demand and protection against link failuresEuropean Community's Seventh Framework ProgramPublicad

Fracture strength testing at the micron-scale on an ultra-fine grained WCr10- Ti2 alloy

The fracture strength of a W-Cr10-Ti2 alloy, manufactured through mechanical alloying and subsequent hot isostatic pressing, has been measured through means of micro-cantilever testing at the Culham Materials Research Facility. The material is a product of ongoing work into self-passivating Tungsten alloys at CEIT, Spain [1] and was chosen for this work due to its fine micro-structure (average grain size Heavy ion implantations to a depth of 3.5µm and an average damage of 0.7 and 7dpa were conducted at RBI, Zagreb in order to assess the effects of nuclear fusion relevant irradiation damage on the fracture strength of the material. Nano-indentation with pile-up correction showed an increase in hardness of 10% and 15% respectively. Results from micro-cantilever testing showed an apparent increase in the elastic modulus with implantation. This is not yet fully understood but similar effects have been reported in work on pure Tungsten previously [2]. A decrease in fracture strength by 10% was observed after implantation to 0.7dpa. For the 7dpa implanted material a slight increase in fracture strength was measured. This however changes to a decrease of 15% when normalized to the nano-indentation measured elastic modulus. Explanations for both the increase in the elastic modulus as well as the proportional effect on fracture strength measurements will be discussed

Characteristics of a Green Turtle (Chelonia mydas) Assemblage in Northwestern Florida Determined During a Hypothermic Stunning Event

A hypothermic stunning event (i.e., cold-stunning event) during late Dec. 2000 and early Jan. 2001 involving an unprecedented number of sea turtles provided an opportunity to characterize the green turtle (Chelonia mydas) assemblage in St. Joseph Bay (Gulf County, Florida). In addition to 388 green turtles, the 401 cold-stunned turtles comprised 10 Kemp\u27s ridleys (Lepidochelys kempii) and three loggerheads (Caretta caretta). Most (337/401) of the turtles survived and were eventually released. To place this event in perspective, we categorize sea turtle cold-stunning events in the eastern United States as either acute or chronic. Acute cold-stunning events, like the one in St. Joseph Bay, occur only during unusually cold winters in shallow-water areas (\u3c 2m), where sea turtles are year-round residents. These are short-lived (\u3c 2 wk) events with low mortality rates (\u3c 30%) that affect principally green turtles. Chronic cold-stunning events occur every winter in areas where sea turtles are seasonal residents. These are long-lived (1-3 mo) events with high mortality rates (\u3e 60%) that affect primarily Kemp\u27s ridleys. All of the green turtles from St. Joseph Bay were neritic-phase juveniles, and the mean straight-line carapace length of this group was 36.6 cm (range = 25.0-75.3 cm, SD = 8.9). This assemblage of juvenile green turtles is the first documented along the northern Gulf of Mexico. Sequencing of mtDNA (mitochondrial DNA) from tissue samples taken from 255 of the green turtles revealed that about 81% were from the nesting populations in the United States (Florida) and Mexico (Yucatan). This assemblage is unusual in the United States because it does not have a substantial representation from the nesting population in Costa Rica (Tortuguero), the Atlantic\u27s largest green turtle nesting population. Based on necropsies of 51 of the green turtles, the sex ratio of this assemblage was female-biased (3.25 females: 1 male), which may be a result of warm incubation temperatures on the nesting beaches in Florida. The majority of the material found in the gastrointestinal tracts of the green turtles that died was turtle grass (Thalassia testudinum). This was the first time turtle grass has been identified as the primary diet of juvenile green turtles anywhere in the continental United States. Green turtles in St. Joseph Bay appear to have few direct threats, but the seagrass upon which these turtles primarily forage has suffered extensive damage from boat propellers