13 research outputs found

    The Green Bank North Celestial Cap Pulsar Survey. III. 45 New Pulsar Timing Solutions

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    We provide timing solutions for 45 radio pulsars discovered by the Robert C. Byrd Green Bank Telescope. These pulsars were found in the Green Bank North Celestial Cap pulsar survey, an all-GBT-sky survey being carried out at a frequency of 350 MHz. We include pulsar timing data from the Green Bank Telescope and Low Frequency Array. Our sample includes five fully recycled millisecond pulsars (MSPs, three of which are in a binary system), a new relativistic double neutron star system, an intermediate-mass binary pulsar, a mode-changing pulsar, a 138 ms pulsar with a very low magnetic field, and several nulling pulsars. We have measured two post-Keplerian parameters and thus the masses of both objects in the double neutron star system. We also report a tentative companion mass measurement via Shapiro delay in a binary MSP. Two of the MSPs can be timed with high precision and have been included in pulsar timing arrays being used to search for low-frequency gravitational waves, while a third MSP is a member of the black widow class of binaries. Proper motion is measurable in five pulsars, and we provide an estimate of their space velocity. We report on an optical counterpart to a new black widow system and provide constraints on the optical counterparts to other binary MSPs. We also present a preliminary analysis of nulling pulsars in our sample. These results demonstrate the scientific return of long timing campaigns on pulsars of all types

    A framework to integrate design knowledge reuse and requirements management in engineering design

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    This paper presents a framework to integrate requirements management and design knowledge reuse. The research approach begins with a literature review in design reuse and requirements management to identify appropriate methods within each domain. A framework is proposed based on the identified requirements. The framework is then demonstrated using a case study example: vacuum pump design. Requirements are presented as a component of the integrated design knowledge framework. The proposed framework enables the application of requirements management as a dynamic process, including capture, analysis and recording of requirements. It takes account of the evolving requirements and the dynamic nature of the interaction between requirements and product structure through the various stages of product development. (C) 2007 Elsevier Ltd. All rights reserved

    An engineering design knowledge reuse methodology using process modelling.

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    This paper describes an approach for reusing engineering design knowledge. Many previous design knowledge reuse systems focus exclusively on geometrical data, which is often not applicable in early design stages. The proposed methodology provides an integrated design knowledge reuse framework, bringing together elements of best practice reuse, design rationale capture and knowledge-based support in a single coherent framework. Best practices are reused through the process model. Rationale is supported by product information, which is retrieved through links to design process tasks. Knowledge-based methods are supported by a common design data model, which serves as a single source of design data to support the design process. By using the design process as the basis for knowledge structuring and retrieval, it serves the dual purpose of design process capture and knowledge reuse: capturing and formalising the rationale that underpins the design process, and providing a framework through which design knowledge can be stored, retrieved and applied. The methodology has been tested with an industrial sponsor producing high vacuum pumps for the semiconductor industry

    What do people post on social media relative to low back pain? A content analysis of Australian data

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    Objective: Low back pain is the leading contributor to the global disability burden. The Global Spine Care Initiative (GSCI) recommend patient-centred care to stem the cost of low back pain. One way to enhance patientcentred care is by better understanding what is relevant for people with low back pain. Exploring social media posts about low back pain could offer this insight and provide valuable information for health care professionals to facilitate active participation in patient-centred care. Methods: We used an inductive content analysis method. In the form of social media posts, data on Twitter and Instagram were collected from June to August 2018. The posts were geo-targeted to Australia. We recorded the number of status broadcasts that contained a low back pain keyword and responses. We developed a codebook to describe the data and applied it to identify low back pain themes. Results: We analysed 768 posts containing 457 status broadcasts and 311 responses. Almost half (49%) of status broadcasts about low back pain seemed to seek validation. Expressing sympathy (31%) was the most common response to a status broadcast about low back pain. There were no public responses to 76% of status broadcasts about low back pain. Our analysis yielded two core themes, “hear my pain” and “I feel for you . Conclusions: Posts about low back pain on social media often seem to suggest that the person posting is seeking validation. Responses typically express sympathy or a shared experience; yet, there is no response to most social media posts about low back pain

    Does cloud computing have a silver lining?

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    Despite the language of immateriality and weightlessness, network communications have a significant materiality and weight when considered from the standpoint of production, consumption and recycling. In this paper, we concentrate on the energy signatures of the server industry on which internet communications depend, with special consideration of Google server farms. The move towards thin clients and cloud computing raises the stakes for the server farm business, and makes it more urgent to confront the finite environment in which information circulates. We assess recent and near-future growth in server traffic, and suggest that business models and regulatory systems have yet to recognise the challenges they pose. <br/

    Large impact basins on Mercury: Global distribution, characteristics, and modification history from MESSENGER orbital data

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    The formation of large impact basins (diameter D ≥ 300 km) was an important process in the early geological evolution of Mercury and influenced the planet's topography, stratigraphy, and crustal structure. We catalog and characterize this basin population on Mercury from global observations by the MESSENGER spacecraft, and we use the new data to evaluate basins suggested on the basis of the Mariner 10 flybys. Forty-six certain or probable impact basins are recognized; a few additional basins that may have been degraded to the point of ambiguity are plausible on the basis of new data but are classified as uncertain. The spatial density of large basins (D ≥ 500 km) on Mercury is lower than that on the Moon. Morphological characteristics of basins on Mercury suggest that on average they are more degraded than lunar basins. These observations are consistent with more efficient modification, degradation, and obliteration of the largest basins on Mercury than on the Moon. This distinction may be a result of differences in the basin formation process (producing fewer rings), relaxation of topography after basin formation (subduing relief), or rates of volcanism (burying basin rings and interiors) during the period of heavy bombardment on Mercury from those on the Moon
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