1,411 research outputs found

    A QoS-Aware Routing Protocol for Real-time Applications in Wireless Sensor Networks

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    The paper presents a quality of service aware routing protocol which provides low latency for high priority packets. Packets are differentiated based on their priority by applying queuing theory. Low priority packets are transferred through less energy paths. The sensor nodes interact with the pivot nodes which in turn communicate with the sink node. This protocol can be applied in monitoring context aware physical environments for critical applications.Comment: 10 pages. arXiv admin note: text overlap with arXiv:1001.5339 by other author

    Columbium-Boron High-Tensile Steel

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    Boron is Seldom used as an alloying element in low carbon steels, although it is recognised to be a potent and cheap alloy to replace sizable quantities of costly elements normally used in harden able steels, to bolster the depth of hardening. Pearlitic steels of commerce encompass a wide range in composition and properties. Amongst these an economically superior class, is the high tensile steels, that are characterised by good strength, high yield-tensile ratio and adequate ductility. In composition, they are of the low carbon low alloy grade, conducive to easy fabri-cation, which is a highly desirable quality. These feat-ures, particularly, the high mechanical properties in the as rolled or normalised condition, is resposible for their special recognition and commercial popularity. The inve-ntion of molybdenum-boron steel1, more popularly known as fortiweld, was a notable addition to this class, as it extended the scope of boron alloying to non martensiti-cally hardenable steels. However attempts to develop a general class of boron-bearing hightensile steel by repla-cement of with molybdenum with a series of common alloying elements were met with rather discouraging results. Based on these observations and the thermal beha-viour of the steel, it was advocated that fortiweld alloy combiation is a unique entity and its superior strength is the out-come of certain delayed phase transformations.Yet, a critical study of the ageing characteristics, mass eff-ect, and response to heat-treatment of the steel gave certain indications that are common to a precipitation hardening phenomenon. If so, substitution of molybdenum by a chemically similar element appeared to be it logical possibility and in view of similarity in structure anti other pbysico-chemical traits, the element columbium was selected for the purpose

    A Facile Spectrophotometric Method for the Determination of Iodate in Table Salt using New Chromogenic Reagents

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    A simple spectrophotometric method has been developed for the determination of iodate in table salt samples using thionin or azure B. The method is based on the reaction of iodate with potassium iodide in an acid  medium to liberate iodine. The liberated iodine bleaches the violet colour of thionin or azure B, which are measured at 600 and 644 nm, respectively. This decrease in absorbance is directly proportional to the initial iodate concentration and obeys Beer’s law in the range of 1–12 μg mL–1 of iodate with thionin and 0.2–16 μg mL–1 of iodate with azure B. The molar absorptivity and Sandell’s sensitivity of using thionin and azure B were found to be 2.7×104 L mol–11 cm–1, 7.9×10–2 μg cm–2 and2.0 6 × 104 L mol–1 cm–1, 0.85×10–2 μg cm–2, respectively. The proposed method has been successfully used for the determination of iodate in table salt samples.KEYWORDS: Iodate determination, spectrophotometry, thionin, azure B

    A Packet Scheduling Strategy in Sensor Networks with SGMH Protocol

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    Data communication in sensor networks can have timing constraints like end to end deadlines. If the deadlines are not met either a catastrophe can happen in hard real time systems or performance deterioration can occur in soft real time systems. In real time sensor networks, the recovery of data through retransmission should be minimized due to the stringent requirements on the worst case time delays. This paper presents the application of Stop and Go Multihop protocol (SGMH) at node level in wireless sensor networks for scheduling and hence to meet the hard real time routing requirements. SGMH is a distributed multihop packet delivery algorithm. The fractions of the total available bandwidth on each channel is assigned to several traffic classes by which the time it takes to traverse each of the hops from the source to the destination is bounded. It is based on the notion of time frames (Tfr). In sensor networks packets can have different delay guarantees. Multiple frame sizes can be assigned for different traffic classes.Comment: 4 pages, 5 figures, IEEE , International Conference ICCCNT 2010, India, IEEE Explore- 2010, ISBN 978-1-4211-6591, pp 1-4, 30th September 201

    Editorial

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    Promoting versatile vaccine development for emerging pandemics

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    The ongoing COVID-19 pandemic has demonstrated the importance of rapid and versatile development of emergency medical countermeasures such as vaccines. We discuss the role of platform vaccines and prototype pathogen research in modern vaccine development, and outline how previous pathogen-specific funding approaches can be improved to adequately promote vaccine R&D for emerging pandemics. We present a more comprehensive approach to financing vaccine R&D, which maximises biomedical pandemic preparedness by promoting flexible vaccine platforms and translatable research into prototype pathogens. As the numerous platform-based SARS-CoV-2 vaccines show, funders can accelerate pandemic vaccine development by proactively investing in versatile platform technologies. For certain emerging infectious diseases, where vaccine research can translate to other related pathogens with pandemic potential, investment decisions should reflect the full social value of increasing overall preparedness, rather than just the value of bringing a vaccine to market for individual pathogens

    The effect of distance on observed mortality, childhood pneumonia and vaccine efficacy in rural Gambia.

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    We investigated whether straight-line distance from residential compounds to healthcare facilities influenced mortality, the incidence of pneumonia and vaccine efficacy against pneumonia in rural Gambia. Clinical surveillance for pneumonia was conducted on 6938 children living in the catchment areas of the two largest healthcare facilities. Deaths were monitored by three-monthly home visits. Children living >5 km from the two largest healthcare facilities had a 2·78 [95% confidence interval (CI) 1·74-4·43] times higher risk of all-cause mortality compared to children living within 2 km of these facilities. The observed rate of clinical and radiological pneumonia was lower in children living >5 km from these facilities compared to those living within 2 km [rate ratios 0·65 (95% CI 0·57-0·73) and 0·74 (95% CI 0·55-0·98), respectively]. There was no association between distance and estimated pneumococcal vaccine efficacy. Geographical access to healthcare services is an important determinant of survival and pneumonia in children in rural Gambia

    Which Market Entry and Product Line Strategies Ought Organisations to Adopt for Emerging Economies?

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    Emerging economies offer tremendous potential for organisations seeking to expand globally and to attain the associated rewards. However, organisations differ in their entrepreneurial tendencies to enter new markets and to introduce new products in emerging economies. Organisations also differ in their abilities to manage their development programs, that is, their execution of different types of projects that lead to success in emerging markets. Finally, organisations differ in which overall measures of program performance are consistent with their strategic objectives. This study provides a literature foundation and conceptual framework designed to understand which market entry and product line strategies and performance measures are appropriate for organisations pursuing strategic success in emerging markets. This study sets forward grounded propositions that different strategic types will vary in their market entry and product line strategies, in the project composition of their development programs, and in the orientations of performance measures used to evaluate their development programs. Prospectors, according to type, will enter emerging economies by introducing new product lines to new customer types, and by emphasizing new-to-the-world products. They will evaluate their development programs with Growth-oriented performance measures. Defenders will more typically occupy secure niches within emerging economies by emphasizing product improvement and cost reduction projects for current types of customers. They will evaluate their development programs with Efficiency-oriented performance measures. Analyzers will either target new customer types with proven products, or serve an existing market niche with new product lines. They will evaluate their development program performance with Strategy-oriented measures
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