330 research outputs found

    Modeling the effects of high strain rate loading on RC columns using Arbitrary Lagrangian Eulerian (ALE) technique

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    In recent years, many studies have been conducted by governmental and nongovernmental organizations across the world in an attempt to better understand the effect of explosive loads on buildings in order to better design against specific threats. This study is intended to contribute to increase the knowledge about how explosions affect reinforced concrete (RC) columns. In this study, a nonlinear model is developed to study the blast response of RC columns subjected to explosive loads. Numerical modeling of RC column under explosive load is presented using advanced finite element code LS DYNA. The obtained numerical model is validated with the experimental test and the results are in substantial agreement with the experimental data. ALE method for blast analysis is presented in the current research. The effects of scaled distance on the damage profile of RC columns are investigated. The results demonstrate that the level of damage increased with describing the scaled distance. Also the results shown duration for the blast loading, and hence the impulse, varies with charge masses at the specified scaled distance. Higher magnitude charge masses produced longer blast loading durations than lower magnitude charge masses. This means that at the same scaled distance, a charge mass of higher magnitude produced a higher impulse than the lower magnitude charge mass. The findings of this research represent the scaled distance is an important parameter that should be taken into account when analyzing the behavior of RC columns under explosive effects. The data collected from this research are being used to improve the knowledge of how structures will respond to a blast event, and improve finite element models for predicting the blast performance of concrete structures.Peer Reviewe

    Correction to: A Randomized Clinical Trial of a Modified Mindfulness-Based Cognitive Therapy for Children Hospitalized with Cancer (Mindfulness, (2021), 12, 1, (141-151), 10.1007/s12671-020-01506-3)

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    In the original published version of this article, Dr. Randye J. Semple was captured as corresponding author instead of Dr. Mojtaba Habibi. Dr. Semple took the role of pre-publication correspondent simply because she is more familiar with the journal�s online submission process than Dr. Habibi. Thus, this erratum is presented to fix the error. The original article has been corrected. © 2020, Springer Science+Business Media, LLC, part of Springer Nature

    Correlation Between Intra-Abdominal Free Fluid and Solid Organ Injury in Blunt Abdominal Trauma

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    Background: In previous studies, the diagnostic value of Focused Assessment with Sonography for Trauma (FAST) has been evaluated but few studies have been performed on the relationship between the amount of free intra-abdominal fluid and organ injury in blunt abdominal trauma. To select patients with a higher probability of intra-abdominal injuries, several scoring systems have been proposed based on the results of FAST. Objectives: The aim of this study was to determine the prognostic value of FAST according to the Huang scoring system and to propose a cut-off point for predicting the presence of intra-abdominal injuries on the Computed Tomography (CT) scan. The correlation between age and Glasgow Coma Scale (GCS) and the presence of intra-abdominal injuries on the CT scan was also assessed. Patients and Methods: This study was performed on 200 patients with severe blunt abdominal trauma who had stable vital signs. For all patients, FAST-ultrasound was performed by a radiologist and the free fluid score in the abdomen was calculated according to the Huang score. Immediately, an intravenous contrast-enhanced abdominal CT scan was performed in all patients and abdominal solid organ injuries were assessed. Results were analyzed using Kruskal-Wallis test, Mann-Whitney test and ROC curves. The correlation between age and GCS and the presence of intra-abdominal injuries on CT-scan was also evaluated. Results: The mean age of the patients was 29.6 ± 18.3 years and FAST was positive in 67% of the subjects. A significant correlation was seen between the FAST score and the presence of organ injury on CT scan (P < 0.001). Considering the cut-off point of 3 for the free fluid score (with a range of 0-8), sensitivity, specificity, positive predictive value and negative predictive value were calculated to be 0.83, 0.98, 0.93, and 0.95, respectively. Age and GCS showed no significant correlation with intra-abdominal injuries. Conclusions: It seems that FAST examination for intra-abdominal fluid in blunt trauma patients can predict intra-abdominal injuries with very high sensitivity and specificity. Using the scoring system can more accurately determine the probability of the presence of abdominal injuries with a cut-off point of three

    Evaluating the Catalytic Performance of La1-xCexNi1-yZnyO3 Nanostructure Perovskites in the Carbon Dioxide Reforming of Methane

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    AbstractIn this research nanostructure perovskites La1-xCexNi1-yZnyO3 were prepared by sol-gel auto-combustion method and their application were evaluated for methane reforming with carbon dioxide and syngas production. Catalysts were designed by Response Surface Method (RSM) based on central composite design (CCD) with three factors of catalyst characteristics, x, y and Tc. The prepared catalysts were examined in methane reforming process at 750 ˚C temperature and atmospheric pressure. Analysis of variance (ANOVA) showed that parameters don’t have any linear effect on catalytic activity and their effect is proportional to square form. Among this investigated parameters, Ni content effect is considerable and calcination temperature (Tc) has a partial effect. In this research R2 value was 94.88%. The optimum catalyst which determined by RSM was La0.60Ce0.40Ni0.81Zn0.19O3 in 747 ˚C calcination temperature that corresponds to empirical result. The XRD characterization of optimum catalyst showed that perovskite catalyst was formed in rhombohedra phase with nanostructure crystals and the SEM of optimum catalyst confirmed the nano scale of prepared particles

    Pregnancy Outcomes Among Hospitalized Patients Infected With 2009 H1N1 Influenza Virus in Qom, Iran, in Oct-Nov. 2009

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    Background: Pandemic H1N1 influenza A 2009 (H1N1/09) virus has been identified as a leading cause of febrile respiratory diseases worldwide, and pregnant women constitute a high risk group. Objectives: To determine the clinical characteristics and outcomes of pregnant women with H1N1 influenza A hospitalized in university hospitals of Qom city in Iran. Patients and Methods: This descriptive retrospective study was conducted using existed data related to October and November 2009. All pregnant women with influenza manifestations were admitted to the hospitals to undergo nasopharyngeal culture. H1N1 virus was confirmed in 11 cases. Data including demographic characteristics, clinical manifestations, laboratory test results, and pregnancy complications was extracted from medical records, and analyzed by descriptive statistics. Results: The mean age of the women was 28.1 ± 4.7 years with a mean gestational age of 28.7 ± 10.9 weeks. The most common clinical manifestations included coughing (100%), fever (87.5%), and dyspnea (75%). The most common abnormal test was anemia (88%). Pregnancy complications included preterm delivery (36.3%), low birth weight (18%), oligohydramnios (9%), gestational diabetes (9%), and fetal distress (9%). Also one (12.5%) wound dehiscence happened. Conclusions: vaccination seems to be necessary to prevent this potentially fatal infectious disease. Furthermore, timely prescription of antiviral medications is recommended to decrease the risk of severe complications

    Investigating the challenges for adopting and implementing of information and communication technologies (ICT) by Isfahan High Schools teachers: Based on the model of barriers in ICT usage

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    Relevance and usefulness of information and communication technologies (ICT) have been investigated in many researches. There are many challenges for ICT users, especially for teachers that act as inhibitor factors for using ICT in their jobs. The main purpose of this paper was to investigate these challenges in the view point of high school teachers in Isfahan city based on ICT use barriers model. In the model, barriers have divided into four groups: organizational, managerial, educational, and financial-instrumental. The research was based on qualitative method. For analyzing data descriptive-analysis method was used. For gathering data, researcher made questionnaire including 5 open ended had been used. Survey population included teachers of all high schools in Isfahan city in 1387-88 academic years. 110 teachers were selected by using cluster random sampling method. For data analysis, content analysis method was used to calculate the mean and frequencies. Findings indicated that most teachers have explained the lack of proper in-service training programs for their use of ICT as the most important obstacles for using ICT in teaching. Lack of suitable managerial strategies for implementing ICT in curriculum, lack of organizational support and lack of financial resources and equipments in schools, respectively, were other barriers in using ICT in Iranian high schools

    Investigating the challenges for adopting and implementing of information and communication technologies (ICT) by Isfahan high schools teachers: Based on the model of barriers in ICT usage

    Get PDF
    Relevance and usefulness of information and communication technologies (ICT) have been investigated in many researches. There are many challenges for ICT users, especially for teachers that act as inhibitor factors for using ICT in their jobs. The main purpose of this paper was to investigate these challenges in the view point of high school teachers in Isfahan city based on ICT use barriers model. In the model, barriers have divided into four groups: organizational, managerial, educational, and financial-instrumental. The research was based on qualitative method. For analyzing data descriptive-analysis method was used. For gathering data, researcher made questionnaire including 5 open ended had been used. Survey population included teachers of all high schools in Isfahan city in 1387-88 academic years. 110 teachers were selected by using cluster random sampling method. For data analysis, content analysis method was used to calculate the mean and frequencies. Findings indicated that most teachers have explained the lack of proper in-service training programs for their use of ICT as the most important obstacles for using ICT in teaching. Lack of suitable managerial strategies for implementing ICT in curriculum, lack of organizational support and lack of financial resources and equipments in schools, respectively, were other barriers in using ICT in Iranian high schools

    Ultrasonographic Assessment of Carpal Tunnel Syndrome Severity: A Systematic Review and Meta-Analysis

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    Objective: The aim of the study was to investigate the overall estimates of cross-sectional areas of the median nerve measured by ultrasonography in accordance with the electrodiagnostic classification of carpal tunnel syndrome severity. Design: MEDLINE (PubMed), Embase (Ovid), and Web of Science were searched for studies reporting the median nerve cross-sectional area measured by ultrasonography for mild, moderate, and severe carpal tunnel syndrome based on electrodiagnostic study. Cross-sectional area values measured at the carpal tunnel inlet were included in the analyses. Results: Overall, 866 citations were retrieved and checked for eligibility. Finally, 16 articles were included for meta-analysis. These studies included a total sample of 2292 wrists including 776 mild, 823 moderate, and 693 severe carpal tunnel syndrome. The pooled analysis revealed a mean cross-sectional area of 11.64 mm 2 (95 confidence interval = 11.23-12.05 mm 2 , P &lt; 0.001) for mild carpal tunnel syndrome, a mean cross-sectional area of 13.74 mm 2 (95 confidence interval = 12.59-14.89 mm 2 , P &lt; 0.001) for moderate carpal tunnel syndrome, and a mean cross-sectional area of 16.80 mm 2 (95 confidence interval = 14.50-19.1 mm 2 , P &lt; 0.001) for severe carpal tunnel syndrome. Conclusions: This is the first meta-analysis that provides the pooled median nerve cross-sectional area values in accordance with the electrodiagnostic classification of carpal tunnel syndrome severity. The values obtained in this study have clinical utility in ultrasonographic assessment of patients with carpal tunnel syndrome. © 2019 Wolters Kluwer Health, Inc. All rights reserved

    Ecological study on the Persian Gulf Martyres Lake, Tehran

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    The ecological study of the Persian Gulf Martyres Lake carried out at the 5 stations between 2013 and 2014. This study identified 35 phytoplankton taxa. The diatoms taxa was dominated and their abundance recorded highest (2000 000 cell. L^-1) in the lake. The annual phytoplankton abundance was measured as 2500 000 cell. L^-1 during the study. The total nitrogen and water temperature were the significant a biotic parameters to increase cyanophytes abundance. Furthermore, 37 zooplankton taxa were identified. The Rotatoria abundance was dominated zooplankton. The annual zooplankton abundance was measured as 72 ind.l-1. Based on the CCA, there was no correlation between Rotatoria abundance and a biotic parameters. The study benthos showed Ephemeroptera and Diptera abundance were dominated; artificial bottom and lack of sediment and organic matters were the main reasons in decreasing of the benthos density. The Chitgar lake is the poorest lake in Iran due to low density of plankton and benthos organisms. The estimation of fish production was 123 kg/ha and for the lake was determaind 16 tonne. The finding display, invasive species was the main fish Chitgar lake that would be negative effect and increase eutriphication trend in the lake. Phosphorus parameter was limited parameters and trophy level recorded low due to high N/P ration in the lake. In overall the Chitgar lake situation is in Oligotrophic category with the low trophy level
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