Facta Universitatis - Series: Physics, Chemistry and Technology最新文献

{"title":"APPLICATION OF MEMBRANE TECHNOLOGY IN THE TREATMENT AND ANALYSIS OF TRIAZINE PESTICIDES IN WATER","authors":"M. Branković, A. Bojić, Darko Anđelković, Tatjana Anđelković","doi":"10.2298/FUPCT1802229B","DOIUrl":"https://doi.org/10.2298/FUPCT1802229B","url":null,"abstract":"The quality of consumable water is decreasing due to increasing water pollution caused by the production and use of human-made chemicals. A significant part of these chemicals are pesticides from the class of triazines since they are widely used in agriculture as herbicides. Water treatment techniques mainly rely on separation science, where the membrane technology has been identified as the most useful. Membrane processes used in water treatment are microfiltration, ultrafiltration, nanofiltration and reverse osmosis. In general, the pollutant retention/rejection by membranes depends on the physicochemical properties of the membrane i.e. membrane material, porosity, pore size and on the properties of the pollutant molecule i.e. size, length, width, molecular weight, hydrophobicity or dipole moment. The pollutant retention also depends on the feed-water composition (organic matter and salt presence, solute concentration, water pH). Thus, effective water treatment depends on the selection of an appropriate type of membrane for a particular type of pollutants. Membrane technology is also significant because it is used in polluted water analysis, more precise as a part of a liquid-phase or solid-phase microextraction. Among several developed membrane-based microextraction methods, in triazine polluted water analysis common are membrane-protected solid-phase microextraction and hollow-fiber liquid-phase microextraction. In this field, researchers tend to achieve membrane-pollutant compatibility through the synthesis of polymeric materials with molecular recognition properties i.e. through a technology called molecular imprinting. HIGHLIGHTS Among several water treatment techniques, the membrane technology has been identified as the most robust and flexible one. The most common water pollutants are triazine pesticides since they are widely used in agriculture as herbicides. The triazines retention by membranes depends on the membrane and triazine molecule properties, but also on the feed-water composition. Thanks to the molecular imprinting technology, membrane technology has found its application in polluted water analysis as a part of sample preparation.","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"39 1","pages":"229-238"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90190766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"COMPARING TEXTUAL, VISUAL AND PRACTICAL METHODS FOR TEACHING PHYSICS","authors":"Lazar Radenković, M. Radović, L. Nešić","doi":"10.2298/FUPCT1803267R","DOIUrl":"https://doi.org/10.2298/FUPCT1803267R","url":null,"abstract":"The same material about friction was covered by the same teacher in three different ways: using only verbal and textual means of communication (text group), using visual aids (diagram group) and using simple experiments (experiment group). The conceptual understanding of each group was evaluated using a test developed for this research. The scores were similar across the groups. HIGHLIGHTS We used friction examples to compare three methods for teaching physics: textual, visual and practical. The first group of students had the textual version of the lesson, with no drawings or diagrams. The second group of students had the usual class, in which the verbal explanation is accompanied by drawings and diagrams on the board. The third group had the complete bundle – verbal explanations, diagrams on the board, and a chance to conduct simple experiments. The effectiveness of teaching methods was evaluated using a conceptual test developed for this research. The scores of all groups were very similar.","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"218 1","pages":"267-283"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83628933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RESEARCH AND EVALUATING OF HYPOTHETICALLY-DEDUCTIVE STUDENT REASONING IN REPUBLIC SERBIA","authors":"B. Radulović, M. Stojanović","doi":"10.2298/FUPCT1803249R","DOIUrl":"https://doi.org/10.2298/FUPCT1803249R","url":null,"abstract":"The goal of this research is an examination of the degree of development of hypothetical-deductive reasoning in general high schools (“gymnasiums”) in the Republic of Serbia. Hypothetical-deductive reasoning is one of the categories of scientific reasoning that can be measured by the Lawson test. The main characteristic of this reasoning is the indication of the degree of development of abstract thinking in adolescents. Adolescents who have developed this method of reasoning can \"operate\" statements, establish complex relationships among them, and combine them in a systematic way by reaching a set of all possible combinations. Hypothetical-deductive reasoning is especially important during experiments in physics teaching. It is therefore important to examine how many students have reached this level of reasoning, and find a way to increase the level of scientific reasoning of students. The research involved 654 high school students from Novi Sad and Backa Palanka. The results of the study showed that around 13% of gymnasiums answered correctly all questions related to hypothetical-deductive reasoning. The obtained data indicate that for most students, hypothetical-deductive reasoning has not been developed. The paper presents the way in which hypothetical-deductive reasoning can be developed or stimulated.","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"150 1","pages":"249-256"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77421710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Single electron capture into arbitrary states of bare projectiles from multi-electron targets","authors":"N. Milojević, I. Mančev","doi":"10.2298/FUPCT1802239M","DOIUrl":"https://doi.org/10.2298/FUPCT1802239M","url":null,"abstract":". The prior form of four-body boundary-corrected first Born (CB1-4B) method is applied to calculate the total cross sections for single electron capture from the K-shell of multi-electron atoms (C, N, O, Ar) by fast projectiles (H + , He 2+ and Li 3+ ). All calculations are carried out for electron capture into the arbitrary n, l, and m final states of the projectiles. The present results are found to be in very good agreement with the available experimental data at intermediate and high impact energies.","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"44 1","pages":"239-247"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75877602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An overview of the scientific research work at the Department of Chemistry of the Faculty of Sciences and Mathematics in Nis based on the defended master’s and PhD theses (1971-2017)","authors":"R. S. Nikolic, D. Kostić","doi":"10.2298/FUPCT1802191N","DOIUrl":"https://doi.org/10.2298/FUPCT1802191N","url":null,"abstract":". This paper presents an overview of the scientific research work carried out at the Department of Chemistry of the Faculty of Sciences and Mathematics of the University of Niš. The scientific research work was realized in the form of masters and PhD theses, as well as within the projects funded by the Ministry of Education, Science and Technological Development of the Republic of Serbia. In the field of chemistry, a total of 110 masters’ theses and 105 doctoral dissertations were defended during the period 1971-2017. Thirty-nine PhD theses are the result of the PhD program introduced 2006. The Chemistry Department gave a significant contribution in the field of education and science by educating a large number of high-quality masters and PhD students some of which have found positions at the Chemistry Department of the Faculty of Sciences and Mathematics in Niš and other Serbian and foreign scientific institutions.","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"30 1","pages":"191-218"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78302419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of reaction conditions on synthesis of steroidal bromohydrin and structural analysis of novel 6α-brom-5β-hydroxy derivative","authors":"Z. I. Kuzminac, R. O. Klisuric, R. Nikolić, N. Sakač","doi":"10.2298/FUPCT1802219K","DOIUrl":"https://doi.org/10.2298/FUPCT1802219K","url":null,"abstract":"Serbia Abstract . Reaction conditions variation and its influence on the reaction of 3β-acetoxy-17- oxa-17a-homoandrost-5-en-16-one with in situ generated hypobromous acid was investigated. Hypobromous acid was generated from N-bromoacetamide or N bromosuccinimide and perchloric acid, and as solvent dioxane, dimethoxyethane or tetrahydrofuran were used. After a series of experiments, it was determined that the number of the reaction products depends on the reagent used, solvents, perchloric acid concentration and the presence/absence of daylight. It has also been found that the yields of certain compounds depend also on the reaction time and temperature. 6α-Bromo-5β-hydroxy derivate is obtained by usage of NBA and 0.28 M perchloric acid in dioxane on daylight. Its structure was confirmed by NMR and X-ray crystal structure","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"08 1","pages":"219-228"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86725902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ELECTROPHORETIC DEPOSITION AS AN EFFECTIVE AND SIMPLE PROCESSING TECHNIQUE FOR FABRICATION OF MAGNESIUM SILICATE HYDRATE (M-S-H) COATINGS ONTO STAINLESS STEEL SUBSTRATES","authors":"Jelena Čović, M. Ranđelović, A. Zarubica, A. Bojić","doi":"10.2298/FUPCT1803297R","DOIUrl":"https://doi.org/10.2298/FUPCT1803297R","url":null,"abstract":"Magnesium silicate hydrate (M-S-H) was prepared via one-pot hydrothermal synthesis and electrophoretically deposited (EPD) onto stainless steel substrate (Type 304), varying different process parameters. The optimal conditions for the EPD process were found to be as follows. A stable suspension of material was achieved using isopropanol containing 1% water as dispersing medium and Mg-nitrate as charging additive. The best coating was obtained after three successively repeated EPD processes at a voltage of 30 V, accompanied by drying at room temperature between each EPD cycle. The coating showed a thickness of 31 µm and very smooth surface. After calcination at 900 °C coating retains its adherence to the substrate but undergoes a structural transformation from poorly crystallized M-S-H to well-crystallized clinoenstatite phase which is known for its biocompatibility. As a result, it densifies and shrinks giving grainy and slightly rough surface. Structural properties and parameters of the magnesium silicate hydrate (M-S-H) and clinoenstatite were acquired by XRD technique, while morphology was examined by the analysis of SEM micrographs. This study demonstrates that: i) M-S-H can be synthesized through simple hydrothermal route starting from simple, low-cost precursors, ii) EPD process is an effective technique for deposition of M-S-H materials onto stainless steel and iii) inosilicate mineral (clinoenstatite) can be successfully obtained from M-S-H by calcination at 900 °C. HIGHLIGHTS Magnesium silicate hydrate (M-S-H) was prepared via a one-pot hydrothermal synthesis. The optimal conditions for the electrolytic deposition process were determined. Kinetics of the process were investigated using the Hamaker`s equation. Clinoenstatite can be successfully obtained from M-S-H by calcination.","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"6 1","pages":"297-308"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73041860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Antimicrobial activity of the secondary metabolites of the genus Bryoria - a review","authors":"Zdravko N. Milovanovic, D. Kostić, V. Milovanović, A. Đorđević, G. Stojanović","doi":"10.2298/FUPCT1802183M","DOIUrl":"https://doi.org/10.2298/FUPCT1802183M","url":null,"abstract":"Main secondary metabolites identified in species of genus Bryoria are fumarprotocetraric and confumarprotocetraric acids, followed by stictic and lobaric acids, atranorin, gyrophoric, vulpinic, barbatolic and usnic acids. This review deals with the antimicrobial activity of substances identified from the genus Bryoria. These data may be useful in predicting the activity of extracts if their composition is known. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant No. 172047].","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"52 1","pages":"183-189"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81871726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RETURN TIME STATISTICS OF EXTREME EVENTS IN DISCRETE NONLINEAR LATTICES","authors":"A. Mančić, A. Maluckov","doi":"10.2298/FUPCT1701035M","DOIUrl":"https://doi.org/10.2298/FUPCT1701035M","url":null,"abstract":"Time statistics of extreme events (EEs) in one-dimensional discrete Salerno lattices is investigated numerically. We show that the dependence of the mean return time of EEs on the amplitude threshold can be used as a criterion to differentiate between various dynamical regimes of the extreme events. Also, we found that dispersion of points on the time probability distribution curve can be an indicator of the appearance of EEs in the system, but it has to be complemented with other statistical measures. The results obtained here can be used to distinguish between different dynamical regimes and as identifiers of the EEs existence in the lattice system.","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"10 1","pages":"035-044"},"PeriodicalIF":0.0,"publicationDate":"2017-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73890340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"THE EFFECT OF OPERATIONAL PARAMETERS ON DECOLOURISATION OF TEXTILE DYES AND COMPARISON EFFICIENCIES OF THE UV/H2O2, FENTON AND PHOTO-FENTON PROCESSES: A REVIEW","authors":"S. Najdanović, J. Mitrović, A. Zarubica, A. Bojić","doi":"10.2298/FUPCT1701023N","DOIUrl":"https://doi.org/10.2298/FUPCT1701023N","url":null,"abstract":"The applicability of advanced oxidation processes (AOPs) such as UV/H 2 O 2 , Fenton and photo-Fenton for removal of textile dyes from wastewater and effect of operational parameters (initial dye concentration, initial H 2 O 2 concentration, initial Fe 2+ concentration and initial pH) on these processes have been reviewed. A numerous works have been reported where AOPs were used for degradation of textile dyes and results showed that they are very effective. By comparing the rate of these processes it was found that photo-Fenton process is more efficient than Fenton and UV/H 2 O 2 process.","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"53 1","pages":"023-034"},"PeriodicalIF":0.0,"publicationDate":"2017-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84493575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}