487 research outputs found

    June 20, 1990 Earthquake of Northern Iran: An Overview

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    On the day of June 20, 1990 at 21:00 GMT (June 21, 1990, at 00:30 local time) a destructive earthquake of magnitude 7.6 shook Northern provinces of Iran. It caused widespread geotechnical and structural damages covering an approximate area of 10,000 sq. km resulting in 37,000 life losses, 100,000 injuries, and 100,000 building failures leaving more than 400,000 people homeless. This paper summarizes the post-earthquake investigations and discusses the general engineering aspects of the June 20, 1990 seismological, geotechnical, and structural aspects of the event. Lessons learned are also discussed

    Testing and validation of a Β; algorithm for cubesat satellites

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    For most satellite missions, it is essential to decrease the satellite angular velocity. The Β algorithm is a common algorithm to stabilize the spacecraft by using magnetorquers. Controlling the satellite using the magnetorquers is part of the attitude control subsystem detumbling mode. Due to oscillating disturbances in the space environment, the required initial conditions needs analysis. As a consequence, the satellite stays in Β detumbling mode for the entire operation. In the detumbling mode, the spacecraft oscillates around its spatial axes. The purpose of this paper is to extend the Β algorithm with a disturbances compensation module and to achieve reduction of satellite’s angular velocity. The developed algorithm is found to be able to reduce satellite’s angular velocity up to 10-11 degrees

    WingSegment: A Computer Vision‐Based Hybrid Approach for Insect Wing Image Segmentation and 3D Printing

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    This article introduces WingSegment, a MATLAB app‐designed tool employing a hybrid approach of computer vision and graph theory for precise insect wing image segmentation. WingSegment detects cells, junctions, Pterostigma, and venation patterns, measuring geometric features and generating Voronoi patterns. The tool utilizes region‐growing, thinning, and Dijkstra's algorithms for boundary detection, junction identification, and vein path extraction. It provides histograms and box plots of geometric features, facilitating comprehensive wing analysis. WingSegment's efficiency is validated through comparisons with established tools and manual measurements, demonstrating accurate results. The tool further enables exporting detected boundaries as FreeCAD macro files for 3D modeling and printing, supporting finite element analysis. Beyond advancing insect wing morphology understanding, WingSegment holds broader implications for diverse planar structures, including leaves and geocells. This tool not only enhances automated geometric analysis and 3D model generation in insect wing studies but also contributes to the broader advancement of analysis, 3D printing, and modeling technologies across various planar structures

    Effects of brassinosteroid (24-epibrassinolide) on yield and quality of grape (Vitis vinifera L.) 'Thompson Seedless'

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    Berry growth ripening process and yield are directly related with nutrition status and phytohormones during fruit growth and development stages. Brassinosteroid (24-epibrassinolide) is one of the plant growth substances that influence different physiological processes including fruit growth and development. In this study, the effect of brassinosteroid (Br) application on the yield and berry quality of 'Thompson Seedless' was investigated in a commercial vineyard, Malayer, Hamedan, Iran. Br solution concentrations of 0, 0.2, 0.4, 0.6 mg·L-1 at five stages (budbreak (S1), prebloom (S2), middle of bloom (S3), post bloom (S4) and veraison (S5) were sprayed. The results showed that the Br application has significant positive effects on bunch morphology and berry quantity and quality. Among levels of Br, the highest yields were related to the application of Br at the rate of 0.6 mg·L-1 in the post bloom and veraison stages, and the lowest was found in the bud break stage. Spraying Br in the post bloom and veraison stages had the greatest effect on berry quality. Also, the highest content of total phenol and antioxidant capacity were obtained with 0.6 mg·L-1 of Br application at veraison stage. In this study, we provided evidence to show that using steroidal plant hormones (Br) may play an essential role in improving the yield and quality of 'Thompson Seedless'

    The survey of the effect of ginger extract on gastric residual volume in mechanically ventilated patients hospitalized in the Intensive Care Units

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    Background and purpose: Delayed gastric emptying in mechanically ventilated patients is common. According to evidences, Ginger can accelerate gastric emptying. This study aimed to determine the effect of ginger extract on gastric residual volume of patients admitted to the Intensive Care Unit. Materials and Methods: In this double-blind randomized controlled clinical trial with before and after schematization, 24 mechanically ventilated patients hospitalized in ICUs were divided into two groups, intervention group (12 patients) and control group (n = 12) after matching for sex and severity of disease. After 48 hours of feeding with a standard gavage solution, the intervention group received 120mg of ginger extract in 4 days and the control group received 5 ml water as placebo in 4 days. The mean residual volume was recorded in the fifth and the sixth days. Data analysis was done with independent and paired T-tests at a significance level of 0.05. Results: The mean residual volume in the first 48 hours was not significantly different between the groups. But after 48 hours of starting treatment, the average of mean and standard deviation of the residual volume in the fifth and sixth days were (24.58±16.81) in intervention group and (108.33±15.09) in control group that according to the Independent T-test showed a significant difference (P <0.0001). Discussion and Conclusion: The result of this study showed that ginger extract reduces gastric residual volume in mechanically ventilated patients hospitalized in intensive care units compared with placebo. © 2013 AENSI Publisher All rights reserved

    The frequency of wing damage in a migrating butterfly

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    The ability to fly is crucial for migratory insects. Consequently, the accumulation of damage on the wings over time can affect survival, especially for species that travel long distances. We examined the frequency of irreversible wing damage in the migratory butterfly Vanessa cardui to explore the effect of wing structure on wing damage frequency, as well as the mechanisms that might mitigate wing damage. An exceptionally high migration rate driven by high precipitation levels in their larval habitats in the winter of 2018–2019 provided us with an excellent opportunity to collect data on the frequency of naturally occurring wing damage associated with long-distance flights. Digital images of 135 individuals of V. cardui were collected and analyzed in Germany. The results show that the hindwings experienced a greater frequency of damage than the forewings. Moreover, forewings experienced more severe damage on the lateral margin, whereas hindwings experienced more damage on the trailing margin. The frequency of wing margin damage was higher in the painted lady butterfly than in the migrating monarch butterfly and in the butterfly Pontia occidentalis following artificially induced wing collisions. The results of this study could be used in future comparative studies of patterns of wing damage in butterflies and other insects. Additional studies are needed to clarify whether the strategies for coping with wing damage differ between migratory and non-migratory species

    Influence maximisation beyond organisational boundaries

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    We consider the problem of choosing influential members within a social network, in order to disseminate a message as widely as possible. While this so-called problem of influence maximisation has been widely studied, little work considers partially-observable networks, where only part of a network is visible to the decision maker. Yet, this is critical in many applications, where an organisation needs to distribute its message far beyond its boundaries and beyond its usual sphere of influence. In this paper, we show that existing algorithms are not sufficient to handle such scenarios. To address this, we propose a set of novel adaptive algorithms that perform well in partially observable settings, achieving an up to 18% improvement on the non-Adaptive state of the art
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