2,250 research outputs found

    Elective Sterilization

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    Adoption of unconventional approaches in construction: The case of cross-laminated timber

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    Achieving sustainable development requires the decoupling of economic growth from the use of non-renewable resources. This depends on industry adopting unconventional approaches to production. This research explores the root causes of barriers to the adoption of such approaches in the construction industry, and applies a behavioural model to assess whether companies are hindered by capability, opportunity or motivation. The long history of lowest-cost tendering in construction has led to a path-dependent lock-in to conventional market-driven objectives of cost and risk reduction; it is suggested that locked-in companies lack the commercial opportunity and hence motivation, rather than the capability, to adopt approaches perceived to increase cost or risk. Such companies will therefore tend to resist unconventional approaches, restricting the physical opportunity for other project participants. This theory is explored in a case study of first adoptions of cross-laminated timber (CLT) in UK projects, using a survey and series of semi-structured interviews. The case study found that project contexts created market niches. This provided designers, who were motivated to use CLT, the opportunity to promote its use in the project. CLT was seen as key to successful resolution of project constraints, thereby providing motivation to other project participants to adopt the material

    Surface Flaw Detection with Ferromagnetic Resonance Probes

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    Eddy current methods of flaw detection have been in use for many years. Frequencies used in this type of flaw detector normally range from tens of kilohertz to a few megahertz. We report on recent progress using a resonant probe which operates in the gigahertz frequency range, and compare its performance with classical eddy current methods

    Surface Flaw Detection with Ferromagnetic Resonance Probes

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    Ferromagnetic probes resonating at microwave frequencies have previously been shown to function as sensitive detectors of surface breaking flaws in metals. A swept frequency mode of operation was used, with the resonance line of the probe displayed on an oscilloscope and the presence of a flaw indicated by a shift of the resonance line. This type of presentation lacks good discrimination between lift-off and and flaw signals and also reduces the probe scanning speed because the entire resonance line must be swept at each measurement point on the test specimen. Our new system operates under cw conditions, with a network analyser type of display giving the probe input impedance in polar coordinates. This provides liftoff discrimination and also enhances sensitivity. Experimental curves and their theoretical interpretations will be presented, and a portable prototype instrument will be described

    Scheduling language and algorithm development study. Volume 3, phase 2: As-built specifications for the prototype language and module library

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    Detailed specifications of the prototype language and module library are presented. The user guide to the translator writing system is included

    Surface Flaw Detection with Ferromagnetic Resonance Probes

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    Small ferromagnetic resonators have been shown to provide effective electromagnetic detectors for surface flaws in magnetic and nonmagnetic metals. As such a resonator is moved along \u27the surface of a test piece it experiences a frequency shift when it passes over a flaw. lwo detection mechanisms are present: (1) an eddy current effect (2) a perturbation of the dc magnetic bias field used to tune the resonator. Results are given for experiments performed on machined slots in aluminum, titanium and steel and on tightly closed fatigue cracks in titanium. Results are also presented for some measurements on titanium aircraft fasteners

    Upregulation of the microRNA cluster at the Dlk1-Dio3 locus in lung adenocarcinoma.

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    Mice in which lung epithelial cells can be induced to express an oncogenic Kras(G12D) develop lung adenocarcinomas in a manner analogous to humans. A myriad of genetic changes accompany lung adenocarcinomas, many of which are poorly understood. To get a comprehensive understanding of both the transcriptional and post-transcriptional changes that accompany lung adenocarcinomas, we took an omics approach in profiling both the coding genes and the non-coding small RNAs in an induced mouse model of lung adenocarcinoma. RNAseq transcriptome analysis of Kras(G12D) tumors from F1 hybrid mice revealed features specific to tumor samples. This includes the repression of a network of GTPase-related genes (Prkg1, Gnao1 and Rgs9) in tumor samples and an enrichment of Apobec1-mediated cytosine to uridine RNA editing. Furthermore, analysis of known single-nucleotide polymorphisms revealed not only a change in expression of Cd22 but also that its expression became allele specific in tumors. The most salient finding, however, came from small RNA sequencing of the tumor samples, which revealed that a cluster of ∼53 microRNAs and mRNAs at the Dlk1-Dio3 locus on mouse chromosome 12qF1 was markedly and consistently increased in tumors. Activation of this locus occurred specifically in sorted tumor-originating cancer cells. Interestingly, the 12qF1 RNAs were repressed in cultured Kras(G12D) tumor cells but reactivated when transplanted in vivo. These microRNAs have been implicated in stem cell pleuripotency and proteins targeted by these microRNAs are involved in key pathways in cancer as well as embryogenesis. Taken together, our results strongly imply that these microRNAs represent key targets in unraveling the mechanism of lung oncogenesis

    Measurement of Surface Crack Opening Displacements Using Microwave Frequency Eddy Currents

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    An electromagnetic NDE technique for measuring the crack opening displacement of surface fatigue cracks is described. A ferromagnetic resonance probe utilizing yttrium-iron-garnet was used to induce eddy currents in an aluminum plate. The crack opening disolacement of a semi-elliptical fatigue crack evaluated at the surface was measured optically at several values of bending stress on the specimen. A technique is presented which allows the crack depth to be calculated from the measured COD at a given stress. The relative phase and magnitude of input vs. output signal to and from the resonating YIG sphere was recorded during the interaction of the FMR probe eddy currents and the fatigue crack. A method is shown to extract quantitative information from these signals and to correlate this information with the crack opening displacement
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