45 research outputs found
Development of lightweight fire retardant, low-smoke, high-strength, thermally stable aircraft floor paneling
Fire resistance mechanical property tests were conducted on sandwich configurations composed of resin-fiberglass laminates bonded with adhesives to Nomex honeycomb core. The test results were compared to proposed and current requirements for aircraft floor panel applications to demonstrate that the fire safety of the airplane could be improved without sacrificing mechanical performance of the aircraft floor panels
Attendance in a national screening program for diabetic retinopathy:a population-based study of 205,970 patients
AIMS: A nationwide diabetic retinopathy (DR) screening program has been established in Denmark since 2013. We aimed to perform an evaluation of adherence to DR screenings and to examine whether non-adherence was correlated to DR progression. METHODS: The population consisted of a register-based cohort, who participated in the screening program from 2013 to 2018. We analyzed age, gender, marital status, DR level (International Clinical DR severity scale, none, mild-, moderate-, severe non-proliferative DR (NPDR) and proliferative DR (PDR)), comorbidities and socioeconomic factors. The attendance pattern of patients was grouped as either timely (no delays > 33%), delayed (delays > 33%) or one-time attendance (unexplained). RESULTS: We included 205,970 patients with 591,136 screenings. Rates of timely, delayed and one-time attendance were 53.0%, 35.5% and 11.5%, respectively. DR level at baseline was associated with delays (mild-, moderate-, severe NPDR and PDR) and one-time attendance (moderate-, severe NPDR and PDR) with relative risk ratios (RRR) of 1.68, 2.27, 3.14, 2.44 and 1.18, 2.07, 1.26, respectively (P < 0.05). Delays at previous screenings were associated with progression to severe NPDR or PDR (hazard ratio (HR) 2.27, 6.25 and 12.84 for 1, 2 and 3+ delays, respectively). Any given delay doubled the risk of progression (HR 2.28). CONCLUSIONS: In a national cohort of 205,970 patients, almost half of the patients attended DR screening later than scheduled or dropped out after first screening episode. This was, in particular, true for patients with any levels of DR at baseline. DR progression in patients with delayed attendance, increased with the number of missed appointments
A multi-biometric iris recognition system based on a deep learning approach
YesMultimodal biometric systems have been widely
applied in many real-world applications due to its ability to
deal with a number of significant limitations of unimodal
biometric systems, including sensitivity to noise, population
coverage, intra-class variability, non-universality, and
vulnerability to spoofing. In this paper, an efficient and
real-time multimodal biometric system is proposed based
on building deep learning representations for images of
both the right and left irises of a person, and fusing the
results obtained using a ranking-level fusion method. The
trained deep learning system proposed is called IrisConvNet
whose architecture is based on a combination of Convolutional
Neural Network (CNN) and Softmax classifier to
extract discriminative features from the input image without
any domain knowledge where the input image represents
the localized iris region and then classify it into one of N
classes. In this work, a discriminative CNN training scheme
based on a combination of back-propagation algorithm and
mini-batch AdaGrad optimization method is proposed for
weights updating and learning rate adaptation, respectively.
In addition, other training strategies (e.g., dropout method,
data augmentation) are also proposed in order to evaluate
different CNN architectures. The performance of the proposed
system is tested on three public datasets collected
under different conditions: SDUMLA-HMT, CASIA-Iris-
V3 Interval and IITD iris databases. The results obtained
from the proposed system outperform other state-of-the-art
of approaches (e.g., Wavelet transform, Scattering transform,
Local Binary Pattern and PCA) by achieving a Rank-1 identification rate of 100% on all the employed databases
and a recognition time less than one second per person
The Compact Linear Collider (CLIC) - 2018 Summary Report
The Compact Linear Collider (CLIC) is a TeV-scale high-luminosity linear collider under development at CERN. Following the CLIC conceptual design published in 2012, this report provides an overview of the CLIC project, its current status, and future developments. It presents the CLIC physics potential and reports on design, technology, and implementation aspects of the accelerator and the detector. CLIC is foreseen to be built and operated in stages, at centre-of-mass energies of 380 GeV, 1.5 TeV and 3 TeV, respectively. CLIC uses a two-beam acceleration scheme, in which 12 GHz accelerating structures are powered via a high-current drive beam. For the first stage, an alternative with X-band klystron powering is also considered. CLIC accelerator optimisation, technical developments and system tests have resulted in an increased energy efficiency (power around 170 MW) for the 380 GeV stage, together with a reduced cost estimate at the level of 6 billion CHF. The detector concept has been refined using improved software tools. Significant progress has been made on detector technology developments for the tracking and calorimetry systems. A wide range of CLIC physics studies has been conducted, both through full detector simulations and parametric studies, together providing a broad overview of the CLIC physics potential. Each of the three energy stages adds cornerstones of the full CLIC physics programme, such as Higgs width and couplings, top-quark properties, Higgs self-coupling, direct searches, and many precision electroweak measurements. The interpretation of the combined results gives crucial and accurate insight into new physics, largely complementary to LHC and HL-LHC. The construction of the first CLIC energy stage could start by 2026. First beams would be available by 2035, marking the beginning of a broad CLIC physics programme spanning 25-30 years
Supported ammonia borane decomposition through enhanced homopolar B B coupling
The thermolytic decomposition of ammonia borane (AB) is known to proceed through the polymeric coupling reaction between -BH3 and -NH3 sites of multiple ammonia borane molecules, which results in the release of hydrogen and other by-products, e.g., ammonia, diborane and borazine. The formation of these by-products concomitantly pollutes the hydrogen stream, and therefore, it is necessary to remove these gases from the product stream. In the current work, a cost effective and easy to synthesize support material, aluminium phosphate (AP), is introduced in AB thermolytic decomposition. An in situ MS study reveals that the AB and AP (w/w) loading ratio of (1 x 4) is the most promising as it is able to minimise the dehydrogenation peak temperature by 18.89 degrees C compared to that of pure AB. Additionally, in the presence of support material, the by-product formation of ammonia is reduced by 70.3%, with a complete suppression in borazine and diborane release. The mechanism behind the by-product suppression of supported AB has been studied through B-11 MAS NMR analysis which suggests that the release of hydrogen occurs through an intermolecular homopolar B-B bonding. The thermogravimetric and kinetic study also reveals that in the case of supported AB decomposition, hydrogen release through B-B interaction is much more efficient than a B-N interaction, thus limiting the possibility of autocatalysis during the supported decomposition reaction
Kinetic model analysis and mechanistic correlation of ammonia borane thermolysis under dynamic heating conditions
Solid state decomposition of ammonia borane has been extensively reported to follow the Avrami-Erofe'ev equation. In this work, thermal analysis of ammonia borane is carried out under dynamic heating conditions under heating rate of 1-5 degrees C/min. The experimentally derived kinetic data is fitted against various solid state decomposition and autocatalytic kinetic models. It has been observed that the two steps of ammonia borane decomposition reactions follow different kinetics. The first step is more likely to be associated with the homogeneous autocatalytic reactions where the second part demonstrates the traditional nucleation growth kinetics. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved
An in situ study on the solid state decomposition of ammonia borane: unmitigated by-product suppression by a naturally abundant layered clay mineral
Borazine is a by-product often encountered in the thermal decomposition of ammonia borane, which leads to an inescapable hindrance towards sustainability and cost effectiveness. In this study, a low cost, low surface area clay mineral, bentonite, was modified and introduced as a support material. Bentonite (42.4 m(2) g(-1)) revealed decomposition characteristics comparable to previously reported high surface area (usually 700-1000 m(2) g(-1)) support materials. In addition, borazine formation from bentonite supported ammonia borane was observed to be completely eliminated. Extensive size strain analysis (Williamson-Hall and Warren-Averbach) indicated that the crystalline parameters were observed to be a considerable factor affecting the dehydrogenation reaction along with the high surface area. However, using in situ XRD and MS characterization, the supported decomposition was attributed to a facile pathway, which was dominated by DADB formation. The proposed pathway justifies the borazine elimination and more steady hydrogen release from AB
Topical non-steroidal anti-inflammatory drugs for central serous chorioretinopathy: a systematic review and meta-analysis
Central serous chorioretinopathy (CSC) is a prevalent exudative maculopathy and the ongoing verteporfin shortage restricts current treatment possibilities. Topical non-steroidal anti-inflammatory drugs (NSAID) have previously been proposed as a treatment for CSC, although its exact efficacy remains unclear. In this systematic review and meta-analysis, we outlined the efficacy of topical NSAIDs for the treatment of CSC. We searched 11 literature databases on 13 December 2022, for any study describing topical NSAID treatment for CSC. Thirteen eligible studies were included with a total of 1001 eyes of 994 patients with CSC. Six studies were case reports, two were cohort studies and five were non-randomized comparative studies. Where specified, topical NSAIDs used were bromfenac 0.09%, diclofenac 0.1%, ketorolac 0.4% and 0.5%, pranoprofen 0.1%, and nepafenac 0.1% and 0.3%. Studies were predominantly of cases with acute CSC and several case studies reported treatment outcomes simultaneously with discontinuation of corticosteroid use, which complicated treatment evaluation. Meta-analyses of comparative studies revealed a statistically significant but clinically irrelevant best-corrected visual acuity improvement of -0.04 logMAR (95% CI: -0.07 to -0.01 logMAR; p = 0.01) at 1-month follow-up, which became statistically insignificant at 3-month follow-up (-0.03 logMAR; 95% CI: -0.06 to 0.003 logMAR; p = 0.08). Further, we found no benefit in complete subretinal fluid resolution at 1-month follow-up (OR: 1.20; 95% CI: 0.81-1.76; p = 0.37) or 3-month follow-up (OR: 1.17; 95% CI: 0.86 to 1.59; p = 0.33). Taken together, available evidence does not support the use of topical NSAIDs for the treatment of CSC.Ophthalmic researc