256 research outputs found
The effect of posture in premature infants on the arterial oxygen saturation, fraction of inspired oxygen and abdominal distension
Background: Putting infants in a posture that reduces oxygen requirement and the complications of the continuous positive airway pressure method is very important. This study aimed at examining the effect of the posture on the arterial oxygen saturation, fraction of inspired oxygen (FIO2) and abdominal distension in premature infants with the respiratory distress syndrome under nasal continuous positive airway pressure. Materials and Methods: In this clinical trial study, 41 premature infants were selected by the simple random sampling and one-group before-after design. The amounts of arterial oxygen saturation, FIO2 and abdominal distension in supine and prone positions were recorded in a data-collection form. Results: There was a significant difference between the mean FIO2 and between the mean abdominal circumference in the prone and supine positions (P=0.022, P<0.001, respectively). There was no significant difference in the mean of arterial oxygen saturation between the two positions (P=0.749). Conclusion: According to the results of the present study, the neonates’ abdominal distension and FIO2 decreased in the prone position. Thus, this supportive, free of charge and effective method can be recommended for these neonates
Construction and performance of the Karkheh Dam Complementary Cut-off Wall: an innovative engineering solution
Construction of a dam cut-off wall is one of the most challenging tasks in dam engineering given the deep excavations involved and the complex interactions between stiff cut-off walls and soft surrounding soils. Here, we present innovative solutions for the development of the Karkheh dam’s complementary cut-off wall in southwest Iran which is among the largest structures of this type worldwide with a maximum depth of 115 m. Due to excessive water seepage and high hydraulic gradient following the reservoir impoundment, additional measures were considered among which was the extension of the existing cut-off wall. The main goal was to decrease the hydraulic gradient of the seepage through the dam foundation. The construction of this new wall, which is called as the complementary wall here, was associated with a number of technical challenges among which were: the connection between the new and old walls; trenching and placing of plastic concrete wall through different dam body zones; and slurry loss during trenching through the dam body zones. The complementary wall was constructed successfully producing invaluable engineering experiences including: design of a U-shaped panel as the connecting panel; design of a new method for grouting through uniformly distributed filter/drain materials; and adding cement-based grouts to the cut-off wall panels to prevent slurry loss. The complementary wall helped to decrease both total seepage and the hydraulic gradient; for instance, in the right abutment, total seepage was cut for 25% and the hydraulic gradient was reduced from 0.2 to 0.095
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Source reconstruction of the 1969 Majene, Sulawesi earthquake and tsunami: A preliminary study
© Copyright 2021 The Author(s). We studied the February 23rd, 1969 M7.0 Majene, Sulawesi earthquake and tsunami. It was followed by tsunami reported at five locations. At least 64 people were killed and severe damage on infrastructures were reported in Majene region. Based on damage
data, we estimated that the maximum intensity of the earthquake was MMI VIII. Focal mechanisms, derived using first motion polarity analysis, indicated that the earthquake had a thrust mechanism. Furthermore, we built hypothetical earthquake scenarios based on a rectangular fault plane of 40 km × 20 km with a homogeneous slip model of 1.5 m. We run the
Open Quake and the JAGURS code to validate the macroseismic and tsunami observation data, respectively. Our best-fitted earthquake model generates maximum intensity of 8+ which is in line with the reported macroseismic data. However, the maximum simulated tsunami height
from all scenario earthquakes is 2.25 m which is smaller than the 4 m tsunami height observed at Pelattoang. The possibility of contribution of another mechanism to tsunami generation requires further investigation.Royal Society, UK (grant number CHL\R1\180173)
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Source reconstruction of the 1969 Sulawesi, Indonesia earthquake and tsunami
This study is funded by the Royal Society (UK) grant number CHL/R1/180173.vEGU21: Gather Online Session NH5.1An M7.0 earthquake followed by moderate tsunami destructed Majene region, western Sulawesi on 23 February 1969. This event claimed at least 64 lives and caused severe damage to infrastructure. In this study, we reconstructed the earthquake and tsunami source of this event by optimising macroseismic and tsunami dataset reported as well as analysed the earthquake focal mechanism. We estimated that the maximum intensity of the earthquake was VIII (in Modified Mercalli Intensity). From the first motion polarity analysis, the earthquake had a thrust mechanism which was plausibly from the Makassar Thrust. Further, deterministic ground motion modelling successfully fits the intensity data. However, thrust earthquake from the Makassar Thrust was unable to reconstruct 4 m tsunami height observed at Pelattoang. The estimated ratio between maximum tsunami run-up height and lateral distribution distance (I2) from the dataset indicates that the tsunami was generated by a local coastal landslide.Royal Society (UK) grant number CHL/R1/180173
Friction stir welding/processing of metals and alloys: A comprehensive review on microstructural evolution
The unique combination of very large strains, high temperatures and high strain rates inherent to friction stir welding (FSW) and friction stir processing (FSP) and their dependency on the processing parameters provides an opportunity to tailor the microstructure, and hence the performance of welds and surfaces to an extent not possible with fusion processe
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A comparative study of far-field tsunami amplitudes and ocean-wide propagation properties: Insight from major trans-Pacific tsunamis of 2010-2015
Copyright © The Author(s) 2018. We studied ocean-wide propagation properties of four recent trans-Pacific tsunamis based on deep-ocean measurements across the Pacific Ocean. First, we analyzed and simulated the 16 September 2015 tsunami generated by the Illapel (Chile) earthquake (Mw 8.4) and compared its ocean-wide propagation with those of three other events: the 2014 Iquique (Mw 8.2), 2010 Maule (Mw 8.8) and 2011 Tohoku (Mw 9.0). The Illapel and Maule tsunami sources are located close to each other and we reconstructed the source spectrum of the larger (i.e. Maule) tsunami by applying spectral deconvolution using the smaller (i.e. Illapel) tsunami as the empirical Green's function. The initial negative phase was found for all four events with durations of 8–29 (Iquique), 20–35 (Illapel), 22–70 (Maule) and 40–79 (Tohoku) min, with the maximum amplitudes of 0.11–0.26, 0.4–0.7, 0.5–2.9 and 1.9–2.5 cm, and the amplitude ratios to the first elevation phases of 20–40 per cent, 22–41 per cent, 29–61 per cent and 12–67 per cent, respectively. Unlike other studies, our results revealed that the duration ({D_{ini}}$ $) and amplitude ({A_{ini}}) of the initial negative phase are directly proportional to the earthquake magnitude ({M_w}$ $) with equations: {M_w} = \;6.129 + 1.629\;{\rm{log}}( {{D_{ini}}} ) and {M_w} = \;8.676 + 0.706\;{\rm{log}}( {{A_{ini}}} )$ $. No relationships were observed between these parameters (i.e. {D_{ini}} and {A_{ini}}$ $) and distance from the source. The amplitudes of far-field DART waves do not vary with distance or strike angle, and depend only on the {M_w}. The average far-field deep-ocean amplitudes ({A_{tsu}}$ $) for the Iquique, Illapel, Maule and Tohoku tsunamis were 0.9, 1.7, 6.0 and 15.0 cm, respectively, yielding the equation: {M_w} = \;8.245 + 0.665\;{\rm{log}}( {{A_{tsu}}} ).Brunel Research Initiative and Enterprise Fun
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Numerical modeling of the subaerial landslide source of the 22 December 2018 Anak Krakatoa volcanic tsunami, Indonesia
The eruption of the Anak Krakatoa volcano (Indonesia) in December 2018 produced a destructive tsunami with maximum runup of 13 m killing 437 people. Since the occurrence of this rare tsunami, it has been a challenge as how to model this tsunami and to reconstruct the network of coastal observations. Here, we apply a combination of qualitative physical modeling and wavelet analyses of the tsunami as well as numerical modeling to propose a source model. Physical modeling of a volcano flank collapse showed that the initial tsunami wave mostly involves a pure-elevation wave. We identified initial tsunami period of 6.3–8.9 min through Wavelet analysis, leading to an initial tsunami dimension of 1.8–7.4 km. Twelve source models were numerically modelled with source dimensions of 1.5–4 km and initial tsunami amplitudes of 10–200 m. Based on the qualities of spectral and amplitude fits between observations and simulations, we constrained the tsunami source dimension and initial amplitude in the ranges of 1.5–2.5 km and 100–150 m, respectively. Our best source model involves potential energy of 7.14 × 1013–1.05 × 1014 J equivalent to an earthquake of magnitude 6.0–6.1. The amplitude of the final source model is consistent with the predictions obtained from published empirical equations.Royal Society, Great Britain Sasakawa Foundatio
Impact of future tsunamis from the Java trench on household welfare: Merging geophysics and economics through catastrophe modelling
This paper presents the first end-to-end example of a risk model for loss of assets in households due to possible future tsunamis. There is a significant need for Government to assess the generic risk to buildings, and the concrete impact on the full range of assets of households, including the ones that are key to livelihoods such as agricultural land, fishing boats, livestock and equipment. Our approach relies on the Oasis Loss Modelling Framework to integrate hazard and risk. We first generate 25 representative events of tsunamigenic earthquakes off the Southern coast of Java, Indonesia. We then create a new vulnerability function based upon the Indonesian household survey STAR1 of how much assets have been reduced in each household after the 2004 tsunami. We run a multinomial logit regression to precisely allocate the probabilistic impacts to bins that correspond with levels of financial reduction in assets. We focus on the town of Cilacap for which we build loss exceedance curves, which represent the financial losses that may be exceeded at a range of future timelines, using future tsunami inundations over a surveyed layout and value of assets over the city. Our loss calculations show that losses increase sharply, especially for events with return periods beyond 250 years. These series of computations will allow more accurate investigations of impacts on livelihoods and thus will help design mitigation strategies as well as policies to minimize suffering from tsunamis.Lloyd's Tercentenary Research Foundation; Lighthill Risk Network; Alan Turing Institute project "Uncertainty Quantification of multi-scale and multiphysics computer models: applications to hazard and climate models", EPSRC EP/N510129/1; Royal Society, the United Kingdom CHL/R1/180173
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Field Surveys and Numerical Simulation of the 2018 Typhoon Jebi: Impact of High Waves and Storm Surge in Semi-enclosed Osaka Bay, Japan
This is a post-peer-review, pre-copyedit version of an article published in Pure and Applied Geophysics. The final authenticated version is available online at: https://doi.org/10.1007/s00024-019-02295-0Tokyo Institute of Technology (Japan Society for the Promotion of Science); Brunel Research Initiative and Enterprise Fund (Brunel University London); Great Britain Sasakawa Foundation; JICA AUN/SEED-Net
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