298 research outputs found

    Use of bioethanol byproduct for supplementary cementitious material production

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    Corn stover has the potential for use as a supplementary cementitious material (SCM) for concrete. The impact of distilled water and dilute acid pretreatments and post-treatments on the pozzolanic reactivity of corn stover ash (CSA) was studied. Additionally, the potential use of a bioethanol byproduct called high lignin residue (HLR) for SCM production was examined. Pretreated CSA and high lignin residue ash (HLRA) increased the early reactivity of cement paste when used as 20% replacement of cement in the system whereas unpretreated CSA was found to severely suppress the hydration reaction. The highest compressive strength was obtained from samples containing HLRA

    Psychometric properties of the Persian version of co-rumination questionnaire

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    Background: Although growing studies support features of co-rumination as a vulnerability factor in internalizing symptoms and positive factor in friendship, little attention has been paid to the psychometric properties of the Co-Rumination Questionnaire (CRQ). Objectives: This study aimed to determine the psychometric properties of the Persian version of this questionnaire. Methods: This research is a descriptive-exploratory study and 550 high school students who were selected by random cluster sampling from schools in Tehran. They completed CRQ, Beck depression inventory-II (BDI-II), and ruminative response scale (RRS) from winter 2014 to summer 2015. Construct validity, internal consistency reliability, and factor structure were investigated. Results: The factor analysis identified two interpretable factors with the eigenvalue higher than 2. The results from concurrent validity measurement in the current study showed that co-rumination has a positive correlation with depression signs (P < 0.01) and rumination response style (P < 0.01). The CRQ validity was determined using the half-split method employing Spearman-Brown (0.82) and Guttman correlation test (0.81) and internal consistency (0.90). According to these values, this questionnaire has acceptable internal consistency reliability. Conclusions: The Persian version of CRQ has reliability and validity for assessing co-rumination among adolescent participants. This study provides primary evidence on the applicability of the Persian version of the CRQ in the Iranian population. Copyright © 2020, Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages, provided the original work is properly cited

    The serological study of cystic echinococcosis and assessment of surgical cases during 5 years (2007- 2011) in Khorram Abad, Iran

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    Background: Echinococcus granulosus is a cestode whose larval stage causes cystic echinococcosis in wild animals, livestock, and human.Objective: The aim of this study is to highlight the seroepidemiology of E. granulosus infection and surgical cases in the general population of Khorram Abad district, southwest of Iran.Materials and Methods: Anti.E. granulosus antibodies were tested in 617 inhabitants in Khorram Abad by enzyme.linked immunoassay and antigen B. The surgical cases of cystic echinococcosis were investigated in Shohaday.e.Ashayer Hospital of Khorram Abad (as a referral center) from 2007 to 2011.Results: In total, 95 (15.4%) of the 617 participants (mean age 39.6 } 17.6 years) had anti.E. granulosus antibodies. Prevalence of infection was more in males (60%) than females (40%), and showed statistical significance (P &lt; 0.001). High.titer antibodies were most prevalent among the subjects aged 20-29 years. There was significant association between the presence of Echinococcus antibodies and the sector of residence, education of volunteers, and occupation (P &lt; 0.05). According to hospital records, 58 cystic echinococcosis cases were referred to the hospital during the 5 years. Among the cases, 28 (48.3%) were men and 30 (51.7%) were women. They were between 4 and 74 years of age (36.6 } 18.9 years). The liver was the organ where most of the hydatid cysts (51.7%) were located, followed by lungs (20.7%).Conclusion: This is the first report of the seroprevalence and contributing factors for E. granulosus infection in the general population in Khorram Abad. The findings confirm the importance of diagnosing human cystic echinococcosis in these regions, given the prevalence rates of surgical cases during the last 5 years, and need further evaluation of the risk factors present.Key words: Cystic echinococcosis, hospitals records, hydatidosis, seroepidemiolog

    Influence of Al2O3 reinforcement on precipitation kinetic of Cu-Cr nanocomposite

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    In this paper, the kinetic of precipitation process in mechanically alloyed Cu-1 wt.% Cr and Cu-1 wt.% Cr/3 wt.% Al2O3 solid solution was compared using differential scanning calorimetry (DSC), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The ageing kinetics in Cu¿Cr and Cu¿Cr/Al2O3 can be described using Johnson¿Mehl¿Avrami (JMA) and Sestak¿Berggren (SB) models, respectively. These different behaviors have been discussed in details. It was found that in presence of Al2O3 reinforcement, the ageing activation energy is decreased and the overall ageing process is accelerated. This behavior is probably due to higher dislocation density previously obtained during ball milling and Al2O3¿Cu interface. TEM observations confirm that Al2O3¿Cu interface and structural defects act as a primary and secondary nucleation sites, respectively.Gobierno de España ENE 2007-67926-C02-0

    Psychometric properties of the Persian version of co-rumination questionnaire

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    Background: Although growing studies support features of co-rumination as a vulnerability factor in internalizing symptoms and positive factor in friendship, little attention has been paid to the psychometric properties of the Co-Rumination Questionnaire (CRQ). Objectives: This study aimed to determine the psychometric properties of the Persian version of this questionnaire. Methods: This research is a descriptive-exploratory study and 550 high school students who were selected by random cluster sampling from schools in Tehran. They completed CRQ, Beck depression inventory-II (BDI-II), and ruminative response scale (RRS) from winter 2014 to summer 2015. Construct validity, internal consistency reliability, and factor structure were investigated. Results: The factor analysis identified two interpretable factors with the eigenvalue higher than 2. The results from concurrent validity measurement in the current study showed that co-rumination has a positive correlation with depression signs (P < 0.01) and rumination response style (P < 0.01). The CRQ validity was determined using the half-split method employing Spearman-Brown (0.82) and Guttman correlation test (0.81) and internal consistency (0.90). According to these values, this questionnaire has acceptable internal consistency reliability. Conclusions: The Persian version of CRQ has reliability and validity for assessing co-rumination among adolescent participants. This study provides primary evidence on the applicability of the Persian version of the CRQ in the Iranian population. Copyright © 2020, Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages, provided the original work is properly cited

    A surrogate model for simulation–optimization of aquifer systems subjected to seawater intrusion

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    This study presents the application of Evolutionary Polynomial Regression (EPR) as a pattern recognition system to predicate the behavior of nonlinear and computationally complex aquifer systems subjected to seawater intrusion (SWI). The developed EPR models are integrated with a multi objective genetic algorithm to examine the efficiency of different arrangements of hydraulic barriers in controlling SWI. The objective of the optimization is to minimize the economic and environmental costs. The developed EPR model is trained and tested for different control scenarios, on sets of data including different pumping patterns as inputs and the corresponding set of numerically calculated outputs. The results are compared with those obtained by direct linking of the numerical simulation model with the optimization tool. The results of the two above-mentioned simulation–optimization (S/O) strategies are in excellent agreement. Three management scenarios are considered involving simultaneous use of abstraction and recharge to control SWI. Minimization of cost of the management process and the salinity levels in the aquifer are the two objective functions used for evaluating the efficiency of each management scenario. By considering the effects of the unsaturated zone, a subsurface pond is used to collect the water and artificially recharge the aquifer. The distinguished feature of EPR emerges in its application as the metamodel in the S/O process where it significantly reduces the overall computational complexity and time. The results also suggest that the application of other sources of water such as treated waste water (TWW) and/or storm water, coupled with continuous abstraction of brackish water and its desalination and use is the most cost effective method to control SWI. A sensitivity analysis is conducted to investigate the effects of different external sources of recharge water and different recovery ratios of desalination plant on the optimal results
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