Efficient Photocatalytic Hydrogen Evolution by Iron Platinum Loaded Reduced Graphene Oxide

In this work, graphene oxide (GO) was prepared by the Hummers method from natural graphite, and modified with iron and platinum nanoparticles by the solvothermal method. The structural order and textural properties of the grapheme-based materials were studied by BET, TEM, XRD, TG-DTA, and XPS techniques. UV−Vis diffuse reflectance spectra indicate the band gap for FePt and FePt-rGO composites to be 3.2 and 2.8 eV, respectively. FePt-rGO showed a hydrogen generation rate higher than that of the FePt nanoparticles. A detailed study of Pt effect on the photocatalytic H2 production rates showed that Pt NPs could act as an effective co-catalyst, enhancing photocatalytic activity of FePt-rGO. The FePt-rGO gave a H2 production rate of 125 μmol g–1 h–1. This is ascribed to the presence of Pt NPs (acting as electron sinks) and graphene oxide (as an electron collector and transporter) in FePt-rGO composites

An agent-based DDM for high level architecture

The Data Distribution Management (DDM) service is one of the six services provided in the Runtime Infrastructure (RTI) of High Level Architecture (HLA). Its purpose is to perform data filtering and reduce irrelevant data communicated between federates. The two DDM schemes proposed for RTI, region based and grid based DDM, are oriented to send as little irrelevant data to subscribers as possible, but only manage to filter part of this information and some irrelevant data is still being communicated. Previously (G. Tan et al., 2000), we employed intelligent agents to perform data filtering in HLA, implemented an agent based DDM in RTI (ARTI) and compared it with the other two filtering mechanisms. The paper reports on additional experiments, results and analysis using two scenarios: the AWACS sensing aircraft simulation and the air traffic control simulation scenario. Experimental results show that compared with other mechanisms, the agent based approach communicates only relevant data and minimizes network communication, and is also comparable in terms of time efficiency. Some guidelines on when the agent based scheme can be used are also give

Hepatitis B virus genotypes in Iran

[No abstract available

The role of phase dynamics in a stochastic model of a passively advected scalar

Collective synchronous motion of the phases is introduced in a model for the stochastic passive advection-diffusion of a scalar with external forcing. The model for the phase coupling dynamics follows the well known Kuramoto model paradigm of limit-cycle oscillators. The natural frequencies in the Kuramoto model are assumed to obey a given scale dependence through a dispersion relation of the drift-wave form $-\beta\frac{k}{1+k^2}$, where $\beta$ is a constant representing the typical strength of the gradient. The present aim is to study the importance of collective phase dynamics on the characteristic time evolution of the fluctuation energy and the formation of coherent structures. Our results show that the assumption of a fully stochastic phase state of turbulence is more relevant for high values of $\beta$, where we find that the energy spectrum follows a $k^{-7/2}$ scaling. Whereas for lower $\beta$ there is a significant difference between a-synchronised and synchronised phase states, and one could expect the formation of coherent modulations in the latter case.Comment: Accepted for publication in Physics of Plasma

The Social Determinants of Risky Driving on the Intercity Roads of Tehran Province, Iran: A Case-Cohort Study

Background: Traffic accidents are the major cause of injuries that endanger the lives of many people annually. It seems that studying the factors and grounds of this type of event including risky driving contributes to the identification of groups at risk and development of preventive programs. Objectives: Given the importance of this issue, we decided to conduct a study to examine the social factors of risky driving. Methods: The present study was implemented based on a case-cohort design. The target community was all the drivers who drove on the intercity roads of Tehran Province. Each driver with and without a history of being guilty in a car accident leading to injury or death during the last 5 years was assigned to the case and control groups, respectively. The questionnaires were completed through a review of documents and interview within the groups. In the analytical analysis, a chi-square test and, if necessary, the odds ratio and confidence intervals were used to determine the relationship between the variables. In each case, the necessary investigation of confounding or interacting variables was performed using regression models and the final model of the factors affecting a risky driving was extracted. Results: From a total of 990 drivers studied, 54 cases (5.5%) were females and 936 (94.5%) were males. The mean and SD of the drivers’ ages were 39.4 and 11.8 years, respectively. People with a driving job, chronic disease, poor socio-economic status, having only a family dispute, without a religious attitude, and under medical supervision (all with P < 0.001), secondary education (P = 0.01), women (P = 0.01), using drugs (P = 0.03) were found to have a greater history of road traffic injuries or deaths. Conclusions: This study showed that gender, education level, occupation, socioeconomic status, medical care, health condition, lifestyle, family conflict, drug abuse history, and religious attitudes are the major social factors of risky driving on the intercity roads of Tehran Province

Psychometric properties of Persian version of the multifactor leadership questionnaire (MLQ)

Background: Outstanding leadership is one of the important and vital concepts in management and educational leadership debates especially in educational organizations such as universities. Thus, effective educational leadership and adopting an appropriate tool to assess leadership in education are crucial in these institutions. The present study was conducted to develop an instrument for measuring the leadership style in faculty members. Methods: In this descriptive cross-sectional study, content and face validity of Multifactor Leadership Questionnaire (MLQ) was examined using the opinions of 10 experienced faculty members as a panel of experts. For construct validity, 210 questionnaires were administered to faculty members of Tehran University of Medical Sciences. Confirmatory factor analysis was run using principal component analysis and Varimax rotation method. The reliability of the scale was measured through internal consistency using Cronbach's alpha formula. Confirmatory factor analysis was used to examine the construct validity of the questionnaire. Data were analyzed using SPSS v.16 and LISREL software. Results: Factor analysis and expert opinion resulted in a questionnaire with 18 items across six subscales including idealized influence, inspirational motivation, intellectual stimulation, individualized consideration, contingent reward, and management by exception. The reliability coefficient of the questionnaire was acceptable (0.90). Confirmatory factor analysis showed that the scale had appropriate goodness of fit. Conclusion: The 18-item Educational Leadership Questionnaire was found to have acceptable validity and reliability for measuring leadership style in the faculty. It is recommended that the questionnaire be administered to a larger sample