فهرست مطالب حسن حذرخانی

Students will benefit from digital world and minimize its threats if they are equipped with digital competency. Digital competency is a loose concept and its meanings vary based on different users. The utilization of poorly defined concepts in the field of general education will result in questionable of the usage. This research aimed to identify the dimensions and sub-dimensions of this concept in general education students. It was conducted with a qualitative approach and multiple case study method. Six internationally recognized frameworks related to the competencies of students in the field of technology were selected and analyzed. The findings showed that a digitally competent student demonstrates five dimensions: managing access to digital content, information, and knowledge; interactive use of knowledge, information, and technology; producing digital content; Improving the health and safety of oneself and others in the digital world; and a critical engagement with the digital world.

The addition of aromatic substrates to electron-deficient alkenes, which in many respects may be considered a Friedel– Crafts type alkylation, is a key reaction in synthetic organic chemistry for the formation of new C-C bonds. Indole and many of its derivatives are relevant units in many naturally occurring compounds, because of their pharmacological and biological properties. Due to the increased nucleophilic reactivity of C3 position of indole ring, it is often used for the subsequent transformations leading to different indole alkaloids. Here I report an efficient catalyst that can catalyzes the electrophilic substitution of indole with electron deficient alkenes. First, Cobalt tris(2-guanidinobenzimidazole), tri chloride (Co(GBI)33+, 3Cl-)  is prepared and then the reaction of indole with beta - nitrostyrene has studied. No product was detected, so the reaction conditions such as the solvents and the amount of catalyst were changed, but the results were the same. After that the chloride moiety of the complex were replaced with tetrakis[(3,5-trifluoromethyl)phenyl]borate (Barf-)anion and the reaction has run on different condition. Our results showed that Cobalt tri(2-guanidinobenzimidazole), tetrakis[(3,5-trifluoromethyl)phenyl]borate (Co(GBI)33+, 3BArf- ) catalyzes the reaction of indole with β - nitrostyrene and afforded the product in high yields. It is noteworthy to mention that using lipophilic anions such as BArf- [(B(3,5-C6H3(CF3)2)4-] , the catalyst could be solubilized in nonpolar solvents that do not compete with substrates for the hydrogen bonding sites.

The present research has made a comparative study of textbooks used for science and chemistry and the environment in Iran and those used for science and chemistry in the United States of America, India and Australia. The statistical population consisted of the textbooks used in the four countries mentioned above. George Bereday’s method for comparative research has been used. The sources used for data collection have been the textbooks and curricula of the countries mentioned above, acquired by means of the Internet or library resources. Then, the content was categorized into sub-components in numerous checklists based on the elements of the curriculum and the main designated environmental components, and the relevant content was extracted and studied. The results of this study pointed out that, although Iranian textbooks have covered most of the topics relevant to environmental education, their content is seldom practical. Moreover, based on the findings of this research, the content pertaining to environmental education in Iranian textbooks is generally informative and news-like in nature and very little attention has been given to critical thinking, analysis or examining environmental issues from various aspects. Therefore, it is recommended that the environmental content in Iranian textbooks be enriched and modified by paying attention more attention to practical topics and also critical thinking, problem-solving skills, real, domestic case studies, and the analysis of environmental events from various aspects.

The threat posed by the Corona virus provided a good opportunity to address technological education in universities and schools. This study was conducted to investigate the challenges and to provide solutions to improve online e-learning and its impact on students' academic achievement during the COVID-19 virus disease era of educational centers by implementing the Teacher-assistant project. The study sample used the form of teaching activities in the online classroom, the item of observing the practical activities of the teacher and members of the educational groups. With the help of a group of students and teachers of chemistry, online education was studied and explored from different aspects. In this study, the challenges and perspectives of online education became more apparent. The data obtained from the research were then summarized and analyzed in a coherent manner and suggestions were made in accordance with each challenge. It is important that e-learning can play an effective role even in face-to-face classes, along with increase participation. Active students, producing a variety of electronic content, increasing the enthusiasm and interest of learners, increase parental satisfaction, how to manage online classroom, improve online learning process, increase interaction in e-learning, increase teacher efficiency and provide internships in a new way with very good results.

Electronic and electrical wastes are special types of wastes that have toxicity, pathogenicity and reliability in the surrounding environment and even in the body of living beings, corrosion of facilities and equipment and the like. The purpose of this study is to investigate and determine the factors influencing the release of nickel element in the environment. To investigate this effect, the effect of various factors such as temperature, pH, humic compounds (secondary herbal products) and time on the release of nickel element from such wastes to water and soil environments were studied. For this purpose, the selected parts were first milled and after preparation, the samples were tested and analyzed separately in water and soil environment and under acidic, neutral and game conditions. The results showed that in the aquatic environment, the rate of penetration of the nickel element is inversely related to the increase in pH and directly to the increase in temperature. The effect of hamic compounds on release is also greater in the play area. Also, the effect of the contact time parameter varies according to the pH changes. In the soil environment, increasing the humidity, acidifying the environment and increasing the humic compounds increase the release of Nickel.

Recently, study of the ecological foot prints and specifically including energy and carbon foort prints have been interested and a plenty of papers and books have been published in this matter over the world. Nevetheless, the ecological foot prints’ literature is not still common in Iranian scientific and public societies. These published papers and books have been mostl focosed on the explanation of carbon and energy foot print concepts. More over, there are a lots of definitions on these concepts from different views and seems that there is a common and general understanding on the meaning of carbon and energy foot prints. Indeed, not only there is not a comprehensive agreement but also there are a lots of confusion on the exact meaning, deffintion and the way and unit of measurement of these foot prints. Despite of these different ideas, the emission of green house gases from consuming of fossile fules and human activities is the common point of view. Here we report a review article on ecological food prints for clarifying of the concept and getting a common understanding.

The aim of this study is the synthesis of 1,4-butanediol (BDO), as chain extender, which is a component of the propellant for improving its mechanical properties. In this research a new and efficient method for the synthesis of BDO from 2bromoethanol has been reported. In roder to do this, first , the hydroxyl group of 2-bromoethanol was protected by triphenylmethyl chloride (TrCl). Then the corresponding grignard compound was synthesized in the presence of magnesium to react wth the equimolar amount of 2-trityloxy bromoethane. Finally deprotection of hydroxyl groups by cerium ammonium nitrate (CAN) resulted in the production of 1,4-butanediol in 93% yield. The intermediate compounds and the product of these reactions were characterized by FTIR and 1HNMR spectroscopies. Availability of the starting materials, high yield and purity of the product and mild reaction conditions are some advantages of the method.