125 research outputs found

    Dataset in support of the Southampton doctoral thesis 'The boatbuilding tradition of the Aegean during the Late Neolithic – Early Bronze Age periods. Typological classification, digital reconstruction and seakeeping assessment'

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    Dataset in support of the Southampton doctoral thesis &#39;The boatbuilding tradition of the Aegean during the Late Neolithic &ndash; Early Bronze Age periods. Typological classification, digital reconstruction and seakeeping assessment&#39; Appendix D - Resistance data and Appendix C - Stability data. This dataset is focused on two appendices: Appendix D - Resistance data. D.1 Resistance data produced by the author via MAXSURF Resistance for this thesis. Appendix C - Stability data C1. Stability data &ndash; STIX and ISO criteria, produced by the author via MAXSURF Stability software for his thesis This research was funded by Southampton Marine and Maritime Institute (SMMI), Vice-Chancellor&#39;s Scholarship, Greek Archaeological Committee UK (GACUK) </span

    Kinetics of epoxy-asphalt oxidation

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    In-depth understanding of the temperature effect on oxidative aging in epoxy-asphalt blends is needed to enable accurate predictions on material response through their service life. Details of the significance of developing prediction models and tools on oxidative aging of pavement materials are presented in a companion paper (Apostolidis et al., Oxidation Simulation of Thin Bitumen Film. AM3P). In this research, the chemical compositional changes of epoxy modified asphalt binders, with and without filler, were analysed after oven-conditioning by means of Fourier transform infrared (FTIR) spectroscopy. With the carbonyl and sulfoxide compounds as aging indices, the sensitivity of chemical compositional changes of bituminous and epoxy-based systems due to the applied temperatures was observed.Accepted Author ManuscriptPavement Engineerin

    Author Correction: AGREE-S: AGREE II extension for surgical interventions: appraisal instrument (Surgical Endoscopy, (2022), 36, 8, (5547-5558), 10.1007/s00464-022-09354-z)

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    This article was updated to correct Alessandro Montedori’s name. Collaborative authorship: The GAP Consortium: Yasser Sami Abdel Dayem, Luca Bertolaccini, Pablo Alonso- Coello, Elie Akl, Manish Chand, John J. Como, Gert J. de Borst, Salomone Di Saverio, Sameh Emile, Bang Wool Eom, Ramon Gorter, George Hanna, Kaisa Immonen, Quirino Lai, Nicolaas Lumen, Joseph L. Mathew, Alessandro Montendori, Martin Moya, Gianluca Pellino, Alvaro Sanabria, Athanasios Saratzis, Neil Smart, Dimitrios Stefanidis, Giovanni Zaninotto

    Efficacy and safety of endoscopic drainage of peripancreatic fluid collections: a retrospective multicenter European study

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    BACKGROUND: Endoscopic ultrasound (EUS)-guided transmural drainage allows treatment of symptomatic peripancreatic fluid collections (PFCs), with lumen-apposing metal stents (LAMS) and double pigtail plastic stents (DPPS) being the 2 most frequently used modalities. METHODS: Consecutive patients undergoing PFC drainage in 10 European centers were retrospectively retrieved. Technical success (successful deployment), clinical success (satisfactory drainage), rate and type of early adverse events, drainage duration and complications on stent removal were evaluated. RESULTS: A total of 128 patients—92 men (71.9%), age 57.2±11.9 years—underwent drainage, with pancreatic pseudocyst (PC) and walled-off necrosis (WON) in 92 (71.9%) and 36 (28.1%) patients, respectively. LAMS were used in 80 (62.5%) patients and DPPS in 48 (37.5%). Technical success was achieved in 124 (96.9%) of the cases, with no difference regarding either the type of stent (P>0.99) or PFC type (P=0.07). Clinical success was achieved in 119 (93%); PC had a better response than WON (91/92 vs. 28/36, P<0.001), but the type of stent did not affect the clinical success rate (P=0.29). Twenty patients (15.6%) had at least one early complication, with bleeding being the most common (n=7/20, 35%). No difference was detected in complication rate per type of stent (P=0.61) or per PFC type (P=0.1). Drainage duration was significantly longer with DPPS compared to LAMS: 88 (70-112) vs. 35 (29-55.3) days, P<0.001. CONCLUSIONS: EUS-guided drainage of PFCs achieves high percentages of technical and clinical success. Drainage using LAMS is of shorter duration, but the complication rate is similar between the 2 modalities

    Optical breakdown acoustics : transduction and sensing underwater

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    This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 191-199).In the sea, infrastructures such as ships, pipelines, and wind turbines are exposed to harsh conditions that can wear down the structures through wave loading and corrosion. Because of these wear mechanisms, maritime structures require regular inspections to identify early signs of damage or fatigue. Currently, inspections are performed visually or with contact acoustic transducers, often by a human diver. However, these methods are slow and costly, and can be hindered by surface irregularities like biofouling. Therefore, new sensing techniques are needed to meet the rising demand for offshore infrastructure monitoring. In this thesis, I develop optical breakdown as an acoustic source for non-contact measurements of underwater structures. Optical breakdown occurs when a high-power laser is focused to a small spot, causing nonlinear interactions between the light and water. A compact plasma forms at the focus and expands explosively, radiating a loud, broadband pressure wave.Since this source is compact, laser-controlled and broadband, it provides unique sensing capabilities that overcome challenges faced by traditional transducers. First, I demonstrate how the breakdown source can be used to remotely measure the internal properties of submerged plates. The source is used to excite leaky Lamb waves in the plates, and broadband elastic dispersion spectra are measured using hydrophones in the water. The dispersion spectra are used to calculate the thicknesses and sound speeds in aluminum, steel, bronze and glass plates of varying thickness. Second, I characterize how the source can be controlled and scaled up by combining acoustic measurements with high-speed images of the breakdown plasma. In general, breakdown produces a loud (>100kPa at 10cm), ultra-broadband (5kHz-5MHz) source, whose characteristics depend on measurement orientation and laser properties.This transduction behavior is explained by modeling the breakdown plasma as an array of laser-driven explosions. When the laser is tightly focused, the plasma is compact, producing a loud and omnidirectional signal. However, for weak focusing and high energies, the plasma lengthens and becomes erratic, producing a weaker signal with less consistent behavior. These results reveal design challenges, tradeoffs and opportunities when adapting the breakdown source for dierent applications.by Athanasios G. Athanassiadis.Ph. D.Ph.D. Massachusetts Institute of Technology, Department of Mechanical Engineerin

    Genome wide high density SNP-based linkage analysis of childhood absence epilepsy identifies a susceptibility locus on chromosome 3p23-p14

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    Childhood absence epilepsy (CAE) is an idiopathic generalised epilepsy (IGE) characterised by typical absence seizures manifested by transitory loss of awareness with 2.5–4 Hz spike-wave complexes on ictal EEG. A genetic component to the aetiology is well recognised but the mechanism of inheritance and the genes involved are yet to be fully established. A genome wide single nucleotide polymorphism (SNP)-based high density linkage scan was carried out using 41 nuclear pedigrees with at least two affected members. Multipoint parametric and non-parametric linkage analyses were performed using MERLIN 1.1.1 and a susceptibility locus was identified on chromosome 3p23-p14 (Zmean = 3.9, p < 0.0001; HLOD = 3.3, α = 0.7). The linked region harbours the functional candidate genes TRAK1 and CACNA2D2. Fine-mapping using a tagSNP approach demonstrated disease association with variants in TRAK1

    Microwave heating simulation of asphalt pavements

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    Microwave heating is a promising heating technology for the maintenance, recycling and deicing of pavement structures. Many experimental studies have been conducted to investigate the microwave heating properties of asphalt mixtures in the laboratory. However, very few studies investigated the application of microwave heating on asphalt pavements. This study aims to simulate microwave heating of paving materials using the finite element method. Results show that the developed three-dimensional model, which couples the physics of electromagnetic waves and heat transfer, shows a great potential for optimizing the design of microwave heating prototypes for pavement applications.Accepted Author ManuscriptPavement Engineerin
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