10,773 research outputs found

    Subject Unrest

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    Roll-to-roll manufacturing of micro components based on advanced printing, structuring and lamination of ceramic tapes is rapidly progressing. This large-scale and cost-effective manufacturing process of ceramic micro devices is however prone to hide defects within the visually opaque tape stacks. To achieve a sustainable manufacturing with zero defects in the future, there is an urgent need for reliable inspection systems. The systems to be developed have to perform high-resolution in-process quality control at high speed. Optical coherence tomography (OCT) is a promising technology for detailed in-depth inspection and metrology. Combined with infrared screening of larger areas it can solve the inspection demands in the roll-to-roll ceramic tape processes. In this thesis state-of-art commercial and laboratory OCT systems, operating at the central wavelength of 1.3 µm and 1.7 µm respectively, are evaluated for detecting microchannels, metal prints, defects and delaminations embedded in alumina and zirconia ceramic layers at hundreds of micrometers beneath surfaces. The effect of surface roughness induced scattering and scattering by pores on the probing radiation, is analyzed by experimentally captured and theoretically simulated OCT images of the ceramic samples, while varying surface roughnesses and operating wavelengths. By extending the Monte Carlo simulations of the OCT response to the mid-infrared the optimal operating wavelength is found to be 4 µm for alumina and 2 µm for zirconia. At these wavelengths we predict a sufficient probing depth of about 1 mm and we demonstrate and discuss the effect of rough surfaces on the detectability of embedded boundaries. For high-precision measurement a new and automated 3D image processing algorithm for analysis of volumetric OCT data is developed. We show its capability by measuring the geometric dimensions of embedded structures in ceramic layers, extracting features with irregular shapes and detecting geometric deformations. The method demonstrates its suitability for industrial applications by rapid inspection of manufactured samples with high accuracy and robustness. The new inspection methods we demonstrate are finally analyzed in the context of measurement uncertainty, both in the axial and lateral cases, and reveal that scattering in the sample indeed affects the lateral measurement uncertainty. Two types of image artefacts are found to be present in OCT images due to multiple reflections between neighboring boundaries and inhomogeneity of refractive index. A wavefront aberration is found in the OCT system with a scanning scheme of two galvo mirrors, and it can be corrected using our image processing algorithm.QC 20140428Multilayer (FP7-NMP4-2007-214122

    Why does low intensity, long-day lighting promote growth in Petunia, Impatiens, and tomato?

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    Numerous reports demonstrate that low intensity, long-day (LD) lighting treatments can promote growth. However, there are conflicting suggestions as to the mechanisms involved. This study examines the responses of Petunia, Impatiens, and tomato to LD lighting treatments and concludes that no single mechanism can explain the growth promotion observed in each case. Petunia showed the most dramatic response to photoperiod; up to a doubling in dry weight (DW) as a result of increasing daylength from 8 h d–1 to 16 h d–1.This could be explained by an increase in specific leaf area (SLA) comparable to that seen with shading. At low photosynthetic photon flux densities (PPFD), the increased leaf area more than compensated for any loss in photosynthetic capacity per unit leaf area. In Petunia, the response may, in part, have also been due to changes in growth habit. Impatiens and tomato showed less dramatic increases in DW as a result of LD lighting, but no consistent effects on SLA or growth habit were observed. In tomato, increased growth was accompanied by increased chlorophyll content, but this had no significant effect on photosynthesis. In both species, increased growth may have been due to a direct effect of LD lighting on photosynthesis. This is contrary to the generally held view that light of approx. 3 – 4 μmol m–2 s–1 is unlikely to have any significant impact on net photosynthesis. Nevertheless, we show that the relationship between PPFD and net photosynthesis is non-linear at low light levels, and therefore low intensity LD lighting can offset respiration very efficiently. Furthermore, a small increase in photosynthesis will have a greater impact when ambient light levels are low

    Bioinformatic Analyses of Unique (Orphan) Core Genes of the Genus Acidithiobacillus: Functional Inferences and Use As Molecular Probes for Genomic and Metagenomic/Transcriptomic Interrogation

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    Indexación: Web of Science.Using phylogenomic and gene compositional analyses, five highly conserved gene families have been detected in the core genome of the phylogenetically coherent genus Acidithiobacillus of the class Acidithiobacillia. These core gene families are absent in the closest extant genus Thermithiobacillus tepidarius that subtends the Acidithiobacillus genus and roots the deepest in this class. The predicted proteins encoded by these core gene families are not detected by a BLAST search in the NCBI non-redundant database of more than 90 million proteins using a relaxed cut-off of 1.0e(-5). None of the five families has a clear functional prediction. However, bioinformatic scrutiny, using pI prediction, motif/domain searches, cellular location predictions, genomic context analyses, and chromosome topology studies together with previously published transcriptomic and proteomic data, suggests that some may have functions associated with membrane remodeling during cell division perhaps in response to pH stress. Despite the high level of amino acid sequence conservation within each family, there is sufficient nucleotide variation of the respective genes to permit the use of the DNA sequences to distinguish different species of Acidithiobacillus, making them useful additions to the armamentarium of tools for phylogenetic analysis. Since the protein families are unique to the Acidithiobacillus genus, they can also be leveraged as probes to detect the genus in environmental metagenomes and metatranscriptomes, including industrial biomining operations, and acid mine drainage (AMD).http://journal.frontiersin.org/article/10.3389/fmicb.2016.02035/ful

    The genetic contribution to severe post-traumatic osteoarthritis

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    Objective: to compare the combined role of genetic variants loci associated with risk of knee or hip osteoarthritis (OA) in post-traumatic (PT) and non-traumatic (NT) cases of clinically severe OA leading to total joint replacement. Methods: A total of 1590 controls, 2168 total knee replacement (TKR) cases (33.2% PT) and 1567 total hip replacement (THR) cases (8.7% PT) from 2 UK cohorts were genotyped for 12 variants previously reported to be reproducibly associated with risk of knee or hip OA. A genetic risk score was generated and the association with PT and NT TKR and THR was assessed adjusting for covariates. Results: For THR, each additional genetic risk variant conferred lower risk among PT cases (OR=1.07, 95% CI 0.96 to 1.19; p=0.24) than NT cases (OR 1.11, 95% CI 1.06 to 1.17; p=1.55×10−5). In contrast, for TKR, each risk variant conferred slightly higher risk among PT cases (OR 1.12, 95% CI 1.07 to 1.19; p=1.82×10−5) than among NT cases (OR 1.08, 95% CI 1.03 to 1.1; p=0.00063). Conclusions: Based on the variants reported to date PT TKR cases have at least as high a genetic contribution as NT cases

    Effect of dietary omega-3 fatty acid supplementation on frailty related phenotypes in older adults: a systematic review and meta-analysis protocol

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    Introduction: The beneficial effect of dietary omega-3 supplementation in younger adults or older people with acute or chronic disease is established. Knowledge is now needed about the effect in medically stable older people. The objective of this study is to examine and assess the evidence for a role of dietary omega-3 polyunsaturated fatty acid (PUFA) supplementation in older adults on (1) muscle mass and muscle strength, (2) inflammatory biomarkers and (3) physical activity. Methods and analysis: A systematic review and data synthesis will be conducted of randomised controlled trials in older people not recruited for any given disease diagnosis. Placebo-controlled studies reporting interventions involving dietary supplementation of omega-3 PUFAs, eicosapentaenoic acid and docosahexaenoic acid will be included. Outcomes must include changes from baseline to last available follow up for one or more of the following: muscle mass, inflammatory biomarkers, physical activity, walking speed, weight change, hand grip strength or muscle strength. Once the search strategy has been carried out, two independent researchers will assess relevant papers for eligibility. Articles up until 31 December 2017 in any language will be included. We will provide a narrative synthesis of the findings from the included studies. Studies will be grouped for meta-analysis according to the outcome(s) provided. Where studies have used the same type of intervention, with the same outcome measure, we will pool the results using a random effects meta-analysis, with standardised mean differences for continuous outcomes and risk ratios for binary outcomes, and calculate 95% CI and two-sided p values for each outcome. Ethics and dissemination: No research ethics approval is required for this systematic review as no confidential patient data will be used. The results of this systematic review will be disseminated through publication in an open-access peer-reviewed journal and through conference presentations

    The Dark Matter Telescope

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    Weak gravitational lensing enables direct reconstruction of dark matter maps over cosmologically significant volumes. This research is currently telescope-limited. The Dark Matter Telescope (DMT) is a proposed 8.4 m telescope with a 3 degree field of view, with an etendue of 260 (m.degree)2(m. degree)^2, ten times greater than any other current or planned telescope. With its large etendue and dedicated observational mode, the DMT fills a nearly unexplored region of parameter space and enables projects that would take decades on current facilities. The DMT will be able to reach 10-sigma limiting magnitudes of 27-28 magnitude in the wavelength range .3 - 1 um over a 7 square degree field in 3 nights of dark time. Here we review its unique weak lensing cosmology capabilities and the design that enables those capabilities.Comment: in-press version with additions; to appear in proceedings of the Dark Matter 2000 conference (Santa Monica, February 2000) to be published by Springe

    Star Formation History and Extinction in the central kpc of M82-like Starbursts

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    We report on the star formation histories and extinction in the central kpc region of a sample of starburst galaxies that have similar far infrared (FIR), 10 micron and K-band luminosities as those of the archetype starburst M82. Our study is based on new optical spectra and previously published K-band photometric data, both sampling the same area around the nucleus. Model starburst spectra were synthesized as a combination of stellar populations of distinct ages formed over the Hubble time, and were fitted to the observed optical spectra and K-band flux. The model is able to reproduce simultaneously the equivalent widths of emission and absorption lines, the continuum fluxes between 3500-7000 Ang, the K-band and the FIR flux. We require a minimum of 3 populations -- (1) a young population of age < 8 Myr, with its corresponding nebular emission, (2) an intermediate-age population (age < 500 Myr), and (3) an old population that forms part of the underlying disk or/and bulge population. The contribution of the old population to the K-band luminosity depends on the birthrate parameter and remains above 60% in the majority of the sample galaxies. Even in the blue band, the intermediate age and old populations contribute more than 40% of the total flux in all the cases. A relatively high contribution from the old stars to the K-band nuclear flux is also apparent from the strength of the 4000 Ang break and the CaII K line. The extinction of the old population is found to be around half of that of the young population. The contribution to the continuum from the relatively old stars has the effect of diluting the emission equivalent widths below the values expected for young bursts. The mean dilution factors are found to be 5 and 3 for the Halpha and Hbeta lines respectively.Comment: 20 pages, uses emulateapj.cls. Scheduled to appear in ApJ Jan 1, 200

    The effects of day and night temperature on Chrysanthemum morifolium: investigating the safe limits for temperature integration

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    The impact of day and night temperatures on pot chrysanthemum (cultivars ‘Covington’ and ‘Irvine’) was assessed by exposing cuttings, stuck in weeks 39, 44, and 49, to different temperature regimes in short-days. Glasshouse heating setpoints of 12°, 15°, 18°, and 21°C, were used during the day, with venting at 2°C above these set-points. Night temperatures were then automatically manipulated to ensure that all of the treatments achieved similar mean diurnal temperatures. Plants were grown according to commercial practice and the experiment was repeated over 2 years. Increasing the day temperature from approx. 19°C to 21°C, and compensating by reducing the night temperature, did not have a significant impact on flowering time, although plant height was increased.This suggests that a temperature integration strategy which involves higher vent temperatures, and exploiting solar gain to give higher than normal day temperatures, should have minimal impact on crop scheduling. However, lowering the day-time temperature to approx. 16°C, and compensating with a warmer night, delayed flowering by up to 2 weeks. Therefore, a strategy whereby, in Winter, more heat is added at night under a thermally-efficient blackout screen may result in flowering delays.Transfers between the temperature regimes showed that the flowering delays were proportional to the amount of time spent in a low day-time temperature regime. Plants flowered at the same time, irrespective of whether they were transferred on a 1-, 2-, or 4-week cycle
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