Pub Date : 2020-01-01DOI: 10.2298/hemind210113003b
N. Božić
The Petnica Science Center (PSC) organized the regular Conference ?A Step into Science?, BOOK AND EVENT REVIEW December 7-12, 2020 online. PSC is an independent, nonprofit organisation for extracurricular, formal, and informal, science education. For the past 38 years, it has been a place of free thinking and innovative ideas for students with strong interests in science and the scientific method. PSC utilizes a peer-to-peer education system, where university students are the tutors of high school students, providing a more informal learning setting to foster the development of scientific ideas. Peer to peer education, as an important aspect of the PSC model is highly beneficial for both young tutors (university students) and their slightly younger students. The primary philosophy is to promote scientific literacy and help high school students to understand the scientific method. By using hands-on approaches to research and science, students are taught how to read appropriate literature, trained in basic research methods, and encouraged to develop their own scientific questions. As students progress through the program, they engage in training and activities that enable them to create their own independent research project proposals. After the project proposal is reviewed and approved, the students have the opportunity to conduct their own research, analyze the results, and write a final peer-reviewed manuscript. The selected manuscripts are traditionally presented at the Petnica annual conference as poster and oral presentations, this time carried out online with great success. More than 100 participants joined the daily presentations and joined in lively discussions on the presented works. The manuscripts are also published in annual proceedings by PSC.
{"title":"The conference “A step into science” 2020 by the Petnica Science Center","authors":"N. Božić","doi":"10.2298/hemind210113003b","DOIUrl":"https://doi.org/10.2298/hemind210113003b","url":null,"abstract":"The Petnica Science Center (PSC) organized the regular Conference ?A Step into Science?, BOOK AND EVENT REVIEW December 7-12, 2020 online. PSC is an independent, nonprofit organisation for extracurricular, formal, and informal, science education. For the past 38 years, it has been a place of free thinking and innovative ideas for students with strong interests in science and the scientific method. PSC utilizes a peer-to-peer education system, where university students are the tutors of high school students, providing a more informal learning setting to foster the development of scientific ideas. Peer to peer education, as an important aspect of the PSC model is highly beneficial for both young tutors (university students) and their slightly younger students. The primary philosophy is to promote scientific literacy and help high school students to understand the scientific method. By using hands-on approaches to research and science, students are taught how to read appropriate literature, trained in basic research methods, and encouraged to develop their own scientific questions. As students progress through the program, they engage in training and activities that enable them to create their own independent research project proposals. After the project proposal is reviewed and approved, the students have the opportunity to conduct their own research, analyze the results, and write a final peer-reviewed manuscript. The selected manuscripts are traditionally presented at the Petnica annual conference as poster and oral presentations, this time carried out online with great success. More than 100 participants joined the daily presentations and joined in lively discussions on the presented works. The manuscripts are also published in annual proceedings by PSC.","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"1 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68381767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-02DOI: 10.2298/HEMIND190211022D
Dijana Drljača, Snežana Maletić, Božo Dalmacija
U ovom radu ispitivano je uklanjanje amonijum-jona iz vodene sredine pomocu zeolita sintetizovanih od razlicitih uzoraka leteceg pepela (termoelektrana Ugljevik (U), Stanari (S) i Gacko (G)) alkalnim fuzionim postupkom uz naknadnu hidrotermalnu obradu. Sintezom su dobijeni sljedeci uzorci zeolita Ugljevik fuzioni (UF), Stanari fuzioni (SF), i Gacko fuzioni (GF). Serijom eksperimenata ispitano je ravnotežno vrijeme kontakta dobijenih zeolita i model rastvora, uticaj pH vrijednosti, kao i zavisnost adsorpcije od pocetne koncentracije amonijum-jona. Ispitivanjem kinetike adsorpcionog procesa ustanovljeno je da proces adsorpcije na svim zeolitima prati Elovicev model. Najveca kolicina adsorbovanog NH 4 + /g zeolita određena je pri pH vrijednosti 8. Ispitivanje adsorpcionih izotermi pokazuje bolje slaganje dobijenih rezultata sa Lengmirovim modelom za uzorak zeolita SF, i Tempkinovim modelom za uzorke zeolita UF i GF. Regenerisani zeoliti (UFr, SFr i GFr) pokazuju približan kapacitet adsorpcije amonijum-jona (za UFr 10,3 mg NH 4 + /g; za SFr 12,0 mg NH 4 + /g i za GFr 7,8 mg NH 4 + /g) kao i originalni zeoliti (za UF 12,2 mg NH 4 + /g; za SF 11,9 mg NH 4 + /g i za GF 14,3 mg NH 4 + /g). Primjena originalnih i regenerisanih zeolita na realnom uzorku otpadne vode potvrđuje konstataciju da su sintetizovani zeoliti na bazi leteceg pepela materijal sa velikim potencijalom za uklanjanje amonijum-jona iz otpadnih voda.
在这项工作中，研究了用不同样品的鸟灰（U）、Stanari（S）和Gacko（G）合成的沸石通过碱性熔融和置换水热工艺从水环境中去除铵离子。合成了以下沸石-碳融合（UF）、Stanari fuzioni（SF）和Gacko fuzioni（GF）样品。在与沸石和溶剂模型的稳定接触状态下，研究了一系列实验，包括pH的影响以及吸附对铵离子初始浓度的依赖性。吸附过程的动力学已经确定，在所有沸石上的吸附过程遵循Elovic模型。在pH值为8时，沸石吸附NH4+的量最大。吸附等温线研究表明，SF沸石样品的Lengmir模型和UF和GF沸石样品的Tempkin模型的结果更好地一致。再生沸石（UFr，SFr i GFr）pokazuju približan kapacitet adsorpcije amonijum jona。在实际废水样品中使用原始沸石和再生沸石证实了合成沸石基于从废水中去除铵离子的高潜力的发现。
{"title":"Uklanjanje amonijum – jona zeolitima sintetizovanih alkalnim fuzionim postupkom od različitih vrsta letećeg pepela","authors":"Dijana Drljača, Snežana Maletić, Božo Dalmacija","doi":"10.2298/HEMIND190211022D","DOIUrl":"https://doi.org/10.2298/HEMIND190211022D","url":null,"abstract":"U ovom radu ispitivano je uklanjanje amonijum-jona iz vodene sredine pomocu zeolita sintetizovanih od razlicitih uzoraka leteceg pepela (termoelektrana Ugljevik (U), Stanari (S) i Gacko (G)) alkalnim fuzionim postupkom uz naknadnu hidrotermalnu obradu. Sintezom su dobijeni sljedeci uzorci zeolita Ugljevik fuzioni (UF), Stanari fuzioni (SF), i Gacko fuzioni (GF). Serijom eksperimenata ispitano je ravnotežno vrijeme kontakta dobijenih zeolita i model rastvora, uticaj pH vrijednosti, kao i zavisnost adsorpcije od pocetne koncentracije amonijum-jona. Ispitivanjem kinetike adsorpcionog procesa ustanovljeno je da proces adsorpcije na svim zeolitima prati Elovicev model. Najveca kolicina adsorbovanog NH 4 + /g zeolita određena je pri pH vrijednosti 8. Ispitivanje adsorpcionih izotermi pokazuje bolje slaganje dobijenih rezultata sa Lengmirovim modelom za uzorak zeolita SF, i Tempkinovim modelom za uzorke zeolita UF i GF. Regenerisani zeoliti (UFr, SFr i GFr) pokazuju približan kapacitet adsorpcije amonijum-jona (za UFr 10,3 mg NH 4 + /g; za SFr 12,0 mg NH 4 + /g i za GFr 7,8 mg NH 4 + /g) kao i originalni zeoliti (za UF 12,2 mg NH 4 + /g; za SF 11,9 mg NH 4 + /g i za GF 14,3 mg NH 4 + /g). Primjena originalnih i regenerisanih zeolita na realnom uzorku otpadne vode potvrđuje konstataciju da su sintetizovani zeoliti na bazi leteceg pepela materijal sa velikim potencijalom za uklanjanje amonijum-jona iz otpadnih voda.","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"73 1","pages":"249-264"},"PeriodicalIF":0.9,"publicationDate":"2019-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68381119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-02DOI: 10.2298/HEMIND190328023M
Slavica Mihajlović, Ž. Sekulić, J. Stojanovic, Vladan Kašić, M. Sokić, M. Blagojev
Kvalitet sirovina u prirodi, pa tako i kvarcnog peska i kvarcita, varira od ležista do ležista. U kojim industrijskim granama mogu da nađu svoju primenu nakon određenih postupaka pripreme, zavisi upravo od njihovog kvaliteta. Potencijlni aspekti primene materijala na bazi ovih sirovina su: u industriji građevinskih i vatrostalnih materijala, keramike i stakla, zatim u metalurgiji, livarstvu i za proizvodnju filtera za preciscavanje vode. Geoloska istraživanja na podrucju centralne Srbije, u reonu opstine Rekovac rezultirala su identifikacijom pojava kvarcnog peska „Ursule“ i kvarcita „Velika Krusevica“. Preliminarna laboratorijska ispitivanja su potvrdila mogucnost primene kvarcnog peska u industriji građevinskih materijala za dobijanje betona, maltera, proizvoda za zavrsne radove u građevinarstvu. Kvarcit se može koristiti u industriji vatrostalnih materijala i metalurgiji, dok je primena u industriji stakla moguca za obojeno staklo i to nakon uklanjanja oksida Fe. Rezultati istraživanja ukazuju na opravdanost daljih detaljnih geoloskih istraživanja u cilju potpunije karakterizacije kvarcnog peska „Ursule“ i kvarcita „Velika Krusevica“.
{"title":"Preliminarna ispitivanja kvarcnih sirovina sa područja opštine Rekovac","authors":"Slavica Mihajlović, Ž. Sekulić, J. Stojanovic, Vladan Kašić, M. Sokić, M. Blagojev","doi":"10.2298/HEMIND190328023M","DOIUrl":"https://doi.org/10.2298/HEMIND190328023M","url":null,"abstract":"Kvalitet sirovina u prirodi, pa tako i kvarcnog peska i kvarcita, varira od ležista do ležista. U kojim industrijskim granama mogu da nađu svoju primenu nakon određenih postupaka pripreme, zavisi upravo od njihovog kvaliteta. Potencijlni aspekti primene materijala na bazi ovih sirovina su: u industriji građevinskih i vatrostalnih materijala, keramike i stakla, zatim u metalurgiji, livarstvu i za proizvodnju filtera za preciscavanje vode. Geoloska istraživanja na podrucju centralne Srbije, u reonu opstine Rekovac rezultirala su identifikacijom pojava kvarcnog peska „Ursule“ i kvarcita „Velika Krusevica“. Preliminarna laboratorijska ispitivanja su potvrdila mogucnost primene kvarcnog peska u industriji građevinskih materijala za dobijanje betona, maltera, proizvoda za zavrsne radove u građevinarstvu. Kvarcit se može koristiti u industriji vatrostalnih materijala i metalurgiji, dok je primena u industriji stakla moguca za obojeno staklo i to nakon uklanjanja oksida Fe. Rezultati istraživanja ukazuju na opravdanost daljih detaljnih geoloskih istraživanja u cilju potpunije karakterizacije kvarcnog peska „Ursule“ i kvarcita „Velika Krusevica“.","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"46 1","pages":"265-274"},"PeriodicalIF":0.9,"publicationDate":"2019-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79668360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.2298/hemind181019005p
A. Popovic, Sonja Milićević, V. Milošević, Branislav Ivošević, Jelena Čarapić, V. Jovanović, D. Povrenović
Industrial wastewater contains recalcitrant organic compounds with a very complex chemical structure, built of molecules with long chains of carbon atoms and attached different functional groups. Chemical or biological treatments used for removal of these compounds are being replaced with more efficient non-commercial wastewater treatments. Advanced oxidation processes overcome limitations of conventional methods regarding formation of by-products during degradation of recalcitrant organic compounds. The Fenton process, or use of the Fenton?s reagent, has became one of the most utilized processes due to simplicity, economy and accessible amounts of ferrous iron and hydrogen-peroxide, which are used in the process. In specific, the Fenton?s reagent is a catalytic-oxidative mixture of these two components. The ferrous iron Fe2+ initiates and catalyzes decomposition of H2O2, resulting in generation of hydroxyl radicals, which are the main radical species in the process able to detoxify several organic pollutants by oxidation. In addition, other mechanisms besides formation of hydroxyl radicals may occur during the Fenton process and participate in degradation of target pollutants. Generally, the treatment efficiency relies upon the physical and chemical properties of target pollutants and the process operating conditions. The main disadvantage of the Fenton process is production of sludge formed by iron hydroxide at certain pH values. An alternative solution for this problem is application of this process in fluidized bed reactors. This paper presents an overview of Fenton and photo-Fenton processes in dispersed systems for removal of different industrial wastewater pollutants. The most important process parameters, required for efficient degradation of recalcitrant organic compounds are also described, such as the catalyst type, pH value, temperature, H2O2 concentration and retention time. Strict control of Fenton process parameters in fluidized bed reactors at desired values can bring these systems to the commercial use.
{"title":"Fenton process in dispersed systems for industrial wastewater treatment","authors":"A. Popovic, Sonja Milićević, V. Milošević, Branislav Ivošević, Jelena Čarapić, V. Jovanović, D. Povrenović","doi":"10.2298/hemind181019005p","DOIUrl":"https://doi.org/10.2298/hemind181019005p","url":null,"abstract":"Industrial wastewater contains recalcitrant organic compounds with a very complex chemical structure, built of molecules with long chains of carbon atoms and attached different functional groups. Chemical or biological treatments used for removal of these compounds are being replaced with more efficient non-commercial wastewater treatments. Advanced oxidation processes overcome limitations of conventional methods regarding formation of by-products during degradation of recalcitrant organic compounds. The Fenton process, or use of the Fenton?s reagent, has became one of the most utilized processes due to simplicity, economy and accessible amounts of ferrous iron and hydrogen-peroxide, which are used in the process. In specific, the Fenton?s reagent is a catalytic-oxidative mixture of these two components. The ferrous iron Fe2+ initiates and catalyzes decomposition of H2O2, resulting in generation of hydroxyl radicals, which are the main radical species in the process able to detoxify several organic pollutants by oxidation. In addition, other mechanisms besides formation of hydroxyl radicals may occur during the Fenton process and participate in degradation of target pollutants. Generally, the treatment efficiency relies upon the physical and chemical properties of target pollutants and the process operating conditions. The main disadvantage of the Fenton process is production of sludge formed by iron hydroxide at certain pH values. An alternative solution for this problem is application of this process in fluidized bed reactors. This paper presents an overview of Fenton and photo-Fenton processes in dispersed systems for removal of different industrial wastewater pollutants. The most important process parameters, required for efficient degradation of recalcitrant organic compounds are also described, such as the catalyst type, pH value, temperature, H2O2 concentration and retention time. Strict control of Fenton process parameters in fluidized bed reactors at desired values can bring these systems to the commercial use.","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"1 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68381308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.2298/hemind190722030h
P. Hałas, J. O. Bera, P Radovan Omorjan, A. Rajić, M. D. Jasin
In many technologies, such as process industry or water supply, there is a need to measure fluid flowrates. Orifice plates are the most common instruments for measuring the fluid flowrate through pipelines due to their many advantages. On the other side, their use increases operating costs of industrial plants and pipelines. In this work, three new forms of orifice plates were designed and tested. These new forms and one standard, which served as a reference, were designed by using the SolidWorks software package. The aim of the new designs was energy savings, and consequently reduction of operating costs. Energy savings can be achieved by such a design, which decreases the orifice plate resistance an element of the pipeline. This was achieved by increasing the open part of the orifice plate permitting the fluid flow. CAD models of orifice plates were transferred to STL files that were further used for CFD simulation as well as 3D printing of experimental replicas. According to the proposed algorithm, the new designs were tested by CFD simulation performed in the COMSOL Multiphysics software package, by using a finite-difference method. Equations used were based on the Reynolds form of Navier-Stokes equations (RANS, Reynolds-averaged Navier-Stokes), and the continuity equation for incompressible fluids. Next, as we have proposed in our algorithm of development of new orifice plate designs, experimental orifice plates were made by using 3D printing technology and FDM (Fused Deposition Modeling) procedure and tested at laboratory conditions. The results of laboratory tests were compared with the results of CFD simulation. A considerable amount of energy saving was indicated, which was achieved already by the first of the three new orifice plate forms (V1) as compared to the reference (V0). For the other two proposed forms, the effect of energy savings was considerably lower. By using CFD simulation, data can be obtained based on which a decision can be made whether the new shape of the measuring device should be corrected or is appropriate for further laboratory tests. Based on the presented results it can be concluded that the proposed testing algorithm proved useful in designing new forms of orifice plates.
{"title":"Analysis of new forms of orifice plates using computational fluid dynamics","authors":"P. Hałas, J. O. Bera, P Radovan Omorjan, A. Rajić, M. D. Jasin","doi":"10.2298/hemind190722030h","DOIUrl":"https://doi.org/10.2298/hemind190722030h","url":null,"abstract":"In many technologies, such as process industry or water supply, there is a need to measure fluid flowrates. Orifice plates are the most common instruments for measuring the fluid flowrate through pipelines due to their many advantages. On the other side, their use increases operating costs of industrial plants and pipelines. In this work, three new forms of orifice plates were designed and tested. These new forms and one standard, which served as a reference, were designed by using the SolidWorks software package. The aim of the new designs was energy savings, and consequently reduction of operating costs. Energy savings can be achieved by such a design, which decreases the orifice plate resistance an element of the pipeline. This was achieved by increasing the open part of the orifice plate permitting the fluid flow. CAD models of orifice plates were transferred to STL files that were further used for CFD simulation as well as 3D printing of experimental replicas. According to the proposed algorithm, the new designs were tested by CFD simulation performed in the COMSOL Multiphysics software package, by using a finite-difference method. Equations used were based on the Reynolds form of Navier-Stokes equations (RANS, Reynolds-averaged Navier-Stokes), and the continuity equation for incompressible fluids. Next, as we have proposed in our algorithm of development of new orifice plate designs, experimental orifice plates were made by using 3D printing technology and FDM (Fused Deposition Modeling) procedure and tested at laboratory conditions. The results of laboratory tests were compared with the results of CFD simulation. A considerable amount of energy saving was indicated, which was achieved already by the first of the three new orifice plate forms (V1) as compared to the reference (V0). For the other two proposed forms, the effect of energy savings was considerably lower. By using CFD simulation, data can be obtained based on which a decision can be made whether the new shape of the measuring device should be corrected or is appropriate for further laboratory tests. Based on the presented results it can be concluded that the proposed testing algorithm proved useful in designing new forms of orifice plates.","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"1 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68381190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-27DOI: 10.2298/HEMIND180213022A
R. Abdullah, Samra Kiran, M. Iqtedar, A. Kaleem, F. Saleem, T. Iftikhar, J. S. Cheema, S. Naz
The exponential increase in the application of 1,4-α-D-glucan glucanohydrolase (GGH) in various fields has placed stress and demand in both qualitative improvement and quantitative enhancement through strain improvement. In the present work, Bacillus subtilis LCBT-15 and Bacillus amyloliquefaciens LCBT-20 were subjected to physical as well as chemical mutagenesis for improving the GGH production potential. Applications of the UV light and ethidium bromide did not cause a significant increase in the enzyme production. However, Ethyl methane sulphonate (EMS) treated co-culture 10 gave 1.3-fold increase in the GGH production, in contrast to the wild co-culture. Different physicochemical parameters including fermentation media, rate of fermentation, temperature, pH, nitrogen and carbon sources and surfactants were also investigated. The M7 medium composition was optimized for GGH production after 48h of incubation at 37 o C and pH 6. The optimum inoculum size was 3.5 ml (1´10 6 cells/ml) in 50 ml of medium. The best carbon and nitrogen sources were lactose (2.5 %); ammonium chloride (1.75 %) and beef extract (1 %), respectively. Optimal GGH production (287 U/ml) was obtained when the medium was supplemented with 0.05% Tween 80. The novelty of this work was exploration of the synergistic phenomena of mutant bacterial co-culture for the enhancement of GGH production.
{"title":"Random mutagenesis and process optimization of bacterial co-culture for hyperproduction of 1, 4-α-D-glucan glucanohydrolase using submerged fermentation","authors":"R. Abdullah, Samra Kiran, M. Iqtedar, A. Kaleem, F. Saleem, T. Iftikhar, J. S. Cheema, S. Naz","doi":"10.2298/HEMIND180213022A","DOIUrl":"https://doi.org/10.2298/HEMIND180213022A","url":null,"abstract":"The exponential increase in the application of 1,4-α-D-glucan glucanohydrolase (GGH) in various fields has placed stress and demand in both qualitative improvement and quantitative enhancement through strain improvement. In the present work, Bacillus subtilis LCBT-15 and Bacillus amyloliquefaciens LCBT-20 were subjected to physical as well as chemical mutagenesis for improving the GGH production potential. Applications of the UV light and ethidium bromide did not cause a significant increase in the enzyme production. However, Ethyl methane sulphonate (EMS) treated co-culture 10 gave 1.3-fold increase in the GGH production, in contrast to the wild co-culture. Different physicochemical parameters including fermentation media, rate of fermentation, temperature, pH, nitrogen and carbon sources and surfactants were also investigated. The M7 medium composition was optimized for GGH production after 48h of incubation at 37 o C and pH 6. The optimum inoculum size was 3.5 ml (1´10 6 cells/ml) in 50 ml of medium. The best carbon and nitrogen sources were lactose (2.5 %); ammonium chloride (1.75 %) and beef extract (1 %), respectively. Optimal GGH production (287 U/ml) was obtained when the medium was supplemented with 0.05% Tween 80. The novelty of this work was exploration of the synergistic phenomena of mutant bacterial co-culture for the enhancement of GGH production.","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"72 1","pages":"341-349"},"PeriodicalIF":0.9,"publicationDate":"2018-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43763537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-27DOI: 10.2298/HEMIND180516027J
Nenad Jevremović, S. Velickovic, M. K. Krušić, V. Panic, T. Volkov-Husović, Radmila Jančić-Heinmann, I. Popovic
The aim of this paper is to present image analysis as a useful technique for fast, reliable and non-destructive detection of dimensional and structural changes in polymers. The possibility of applying image analysis was demonstrated in the case of solvent-induced crystallization of poly(ethylene terephthalate) (PET) containers filled with commonly used organic solvents: chlorobenzene, isophorone, xylene, Espesol, Shellsol A 100, Solvesso 150, propylene glycol, glycerin and water and subjected to the storage stability test at 54 °C for 14 days (CIPAC 1-MT 46.1.3). In addition, the obtained results were analyzed using one-step analysis of variance (ANOVA) combined with the Duncan’s statistical test (p<0.05). According to the achieved results, three main impacts of the presented paper could be distinguished: 1) dimensional and transparency changes could be precisely followed by image analysis in both following cases: for small changes in water, as well as for significant ones in chlorobenzene; 2) a correlation between the changes in the degree of crystallinity and transparency could be obtained without the continuous material testing by DSC; 3) image analysis is potentially applicable for assessment of other crystalline polymers.
本文的目的是介绍图像分析作为一种有用的技术，用于快速，可靠和无损地检测聚合物的尺寸和结构变化。在溶剂诱导结晶的情况下，应用图像分析的可能性在聚对苯二甲酸乙酯(PET)容器中进行了演示，该容器中填充了常用的有机溶剂:氯苯、异戊酮、二甲苯、Espesol、Shellsol A 100、Solvesso 150、丙二醇、甘油和水，并在54°C下进行了14天的储存稳定性测试(CIPAC 1-MT 46.1.3)。采用一步方差分析(ANOVA)结合Duncan’s统计检验对所得结果进行分析(p<0.05)。根据所取得的结果，可以区分出本文的三个主要影响:1)在以下两种情况下，图像分析可以精确地跟踪尺寸和透明度的变化:对于水的微小变化，以及氯苯的显著变化;2)不需要连续的DSC测试材料，结晶度和透明度的变化可以得到相关性;3)图像分析可能适用于其他结晶聚合物的评估。
{"title":"Image analysis as a useful tool for fast detection of dimensional and structural changes of poly(ethylene terephthalate) containers","authors":"Nenad Jevremović, S. Velickovic, M. K. Krušić, V. Panic, T. Volkov-Husović, Radmila Jančić-Heinmann, I. Popovic","doi":"10.2298/HEMIND180516027J","DOIUrl":"https://doi.org/10.2298/HEMIND180516027J","url":null,"abstract":"The aim of this paper is to present image analysis as a useful technique for fast, reliable and non-destructive detection of dimensional and structural changes in polymers. The possibility of applying image analysis was demonstrated in the case of solvent-induced crystallization of poly(ethylene terephthalate) (PET) containers filled with commonly used organic solvents: chlorobenzene, isophorone, xylene, Espesol, Shellsol A 100, Solvesso 150, propylene glycol, glycerin and water and subjected to the storage stability test at 54 °C for 14 days (CIPAC 1-MT 46.1.3). In addition, the obtained results were analyzed using one-step analysis of variance (ANOVA) combined with the Duncan’s statistical test (p<0.05). According to the achieved results, three main impacts of the presented paper could be distinguished: 1) dimensional and transparency changes could be precisely followed by image analysis in both following cases: for small changes in water, as well as for significant ones in chlorobenzene; 2) a correlation between the changes in the degree of crystallinity and transparency could be obtained without the continuous material testing by DSC; 3) image analysis is potentially applicable for assessment of other crystalline polymers.","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"72 1","pages":"351-361"},"PeriodicalIF":0.9,"publicationDate":"2018-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48868647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-27DOI: 10.2298/HEMIND180630023M
M. Milosavljević, Ljiljana Babicev, Svetlana Belošević, D. Daničić, Milena Milošević, Jelena D. Rusmirović, A. Marinković
The innovative laboratory procedure for the synthesis of copper(II) hydroxide in the form of the aqueous suspension was developed. The reaction mechanism consists of the reaction between copper(II) sulphate pentahydrate and sodium carbonate by successive ion exchange of carbonate ions with the hydroxide ones in a multistep process. Production of copper(II) carbonate and sodium sulphate by reacting of copper(II) sulphate with sodium carbonate was followed by addition of sodium hydroxide solution whereby the product, copper(II) hydroxide, was obtained by releasing an equimolar amount of sodium carbonate. It was determined that, the equimolar reaction of copper(II) sulphate and sodium hydroxide lead to the maximal reactants exploitation. Sodium phosphate, formed in the final process stage by addition of 10 % phosphoric acid solution, acted as a copper(II) hydroxide stabilizer. High yield of the product was obtained by optimizing the synthesis parameters: reaction time, molar ratio of reactants and the reaction temperature. The obtained product was formulated to obtain a commercial product, which is used as a fungicide and bactericide.
{"title":"Innovative environmentally friendly technology for copper(II) hydroxide production","authors":"M. Milosavljević, Ljiljana Babicev, Svetlana Belošević, D. Daničić, Milena Milošević, Jelena D. Rusmirović, A. Marinković","doi":"10.2298/HEMIND180630023M","DOIUrl":"https://doi.org/10.2298/HEMIND180630023M","url":null,"abstract":"The innovative laboratory procedure for the synthesis of copper(II) hydroxide in the form of the aqueous suspension was developed. The reaction mechanism consists of the reaction between copper(II) sulphate pentahydrate and sodium carbonate by successive ion exchange of carbonate ions with the hydroxide ones in a multistep process. Production of copper(II) carbonate and sodium sulphate by reacting of copper(II) sulphate with sodium carbonate was followed by addition of sodium hydroxide solution whereby the product, copper(II) hydroxide, was obtained by releasing an equimolar amount of sodium carbonate. It was determined that, the equimolar reaction of copper(II) sulphate and sodium hydroxide lead to the maximal reactants exploitation. Sodium phosphate, formed in the final process stage by addition of 10 % phosphoric acid solution, acted as a copper(II) hydroxide stabilizer. High yield of the product was obtained by optimizing the synthesis parameters: reaction time, molar ratio of reactants and the reaction temperature. The obtained product was formulated to obtain a commercial product, which is used as a fungicide and bactericide.","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"72 1","pages":"363-370"},"PeriodicalIF":0.9,"publicationDate":"2018-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42597384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-15DOI: 10.2298/HEMIND180227021K
D. Kojić, N. Lazić, J. Budinski-Simendic, M. Špírková, P. Dugic, S. Ostojić, J. Pavličević
Primenom stiren-butadienskog kaucuka kao prekursora mreže, i kombinacije nanocestica cađi i silicijum(IV)oksida (SiO 2 ),pri razlicitim phr sadržajima (50/0, 35/15, 25/25, 15/35, 0/50 phr), sintetisani su nanokompoziti sa adekvatnim svojstvima za ekoloski prihvatljive pneumatike. Proucavana je raspodela punila u elastomernoj matrici, i ispitan je uticaj kombinovanih punila na karakteristike mesanja, umrežavanje, kao i na termicka, dinamicko-mehanicka i mehanicka svojstva umreženih nanokompozita. Obrazovanje najvecih aglomerata je uoceno u u strukturi nanokompozita ojacanog sa 25 phr cađi i 25 phr sintetisanog silicijum(IV)oksida. Povecanjem sadržaja silicijum(IV)oksida u kombinovanom punilu, rastu vrednosti minimalnog momenta na 100, 150 i 160 °C (u skladu sa sklonoscu SiO 2 da ucestvuje u punilo-punilo interakcijama). Vreme pocetka umrežavanja i vreme optimalnog umrežavanja se produžavaju dodatkom SiO 2 . Primenom modulovane diferencijalno skenirajuce kalorimetrije i dinamicko-mehanicke analize je utvrđena temperatura prelaska u staklasto stanje. Kompoziti sa kombinovanim punilima ispunjavaju zahteve u industriji pneumatika, nisku vrednost mehanickog faktora gubitaka između 40 i 80 °C, radi smanjenja otpornosti na kotrljanje i ustede u potrosnji goriva, uz istovremeno visoki histerezis na niskim temperaturama (od -20 do 0 °C), u cilju postizanja visoke otpornosti na klizanje na ledu i mokrom kolovozu. Utvrđen je i uticaj dodatka kombinovanog punila na zateznu cvrstocu i otpornost na abraziju sintetisanih nanokompozita.
使用苯乙烯-丁二烯共聚物作为网络中间体，以及具有不同phr含量（50/0、35/15、25/25、15/35、0/50phr）的纳米笼和氧化硅（IV）的组合，已经合成了具有足够的生态可接受的气动性能。研究了纳米复合材料在弹性体基体中的分布，并研究了复合肉、冷冻以及冷冻纳米复合材料的热、动态力学和力学性能的影响。在具有25phr笼和25phr合成氧化硅的纳米复合材料的结构中观察到最大团聚体的研究。Povecanjem sadržaja silicijum（IV）oksida u kombinovanom punilu，rastu vrednosti最小温度为100、150和160°C（u skladu sa sklonoscu SiO2 da ucestvuje u punilo punilo interakcijama）。开始冷冻和最佳冷冻的时间应延长至SiO2。调制差示量热扫描和动态力学分析的应用确定了向玻璃态转变的温度。具有组合燃料的部件满足气动工业的要求，在40至80°C之间的低机械损耗因数可降低滚动阻力并降低燃料消耗，而在低温（-20至0°C）下的高磁滞可实现高冰和湿的巨大阻力。还确定了组合添加剂对合成纳米复合材料的紧密性和电阻的影响。
{"title":"Uticaj kombinovanih aktivnih punila na svojstva elastomernih materijala za ekološki prihvatljive pneumatike","authors":"D. Kojić, N. Lazić, J. Budinski-Simendic, M. Špírková, P. Dugic, S. Ostojić, J. Pavličević","doi":"10.2298/HEMIND180227021K","DOIUrl":"https://doi.org/10.2298/HEMIND180227021K","url":null,"abstract":"Primenom stiren-butadienskog kaucuka kao prekursora mreže, i kombinacije nanocestica cađi i silicijum(IV)oksida (SiO 2 ),pri razlicitim phr sadržajima (50/0, 35/15, 25/25, 15/35, 0/50 phr), sintetisani su nanokompoziti sa adekvatnim svojstvima za ekoloski prihvatljive pneumatike. Proucavana je raspodela punila u elastomernoj matrici, i ispitan je uticaj kombinovanih punila na karakteristike mesanja, umrežavanje, kao i na termicka, dinamicko-mehanicka i mehanicka svojstva umreženih nanokompozita. Obrazovanje najvecih aglomerata je uoceno u u strukturi nanokompozita ojacanog sa 25 phr cađi i 25 phr sintetisanog silicijum(IV)oksida. Povecanjem sadržaja silicijum(IV)oksida u kombinovanom punilu, rastu vrednosti minimalnog momenta na 100, 150 i 160 °C (u skladu sa sklonoscu SiO 2 da ucestvuje u punilo-punilo interakcijama). Vreme pocetka umrežavanja i vreme optimalnog umrežavanja se produžavaju dodatkom SiO 2 . Primenom modulovane diferencijalno skenirajuce kalorimetrije i dinamicko-mehanicke analize je utvrđena temperatura prelaska u staklasto stanje. Kompoziti sa kombinovanim punilima ispunjavaju zahteve u industriji pneumatika, nisku vrednost mehanickog faktora gubitaka između 40 i 80 °C, radi smanjenja otpornosti na kotrljanje i ustede u potrosnji goriva, uz istovremeno visoki histerezis na niskim temperaturama (od -20 do 0 °C), u cilju postizanja visoke otpornosti na klizanje na ledu i mokrom kolovozu. Utvrđen je i uticaj dodatka kombinovanog punila na zateznu cvrstocu i otpornost na abraziju sintetisanih nanokompozita.","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"72 1","pages":"293-303"},"PeriodicalIF":0.9,"publicationDate":"2018-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41555965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-15DOI: 10.2298/HEMIND180530020J
Z. Janković, M. Pavlovic, Marijana R. Pantović Pavlović, N. Nikolić, V. Zečević, M. Pavlović
This manuscript presents experimental studies of composite materials based on poly (L lactic acid) (PLLA) and poly (3-hydroxybutyrate) (PHB) matrices filled with electrolytic copper powder, having a very high dendritic structure. Volume fractions of the copper powder used as filler in all prepared composites were varied in the range 0.5-6.0 vol.%. Samples were prepared by hot moulding injection at 170 °C. Influence of particle size and morphology, as well as the influence of matrix type on conductivity and percolation threshold of the obtained composites were examined. Characterization included: electrical conductivity measurements using AC impedance spectroscopy (IS), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and Fourier-transform Infrared spectroscopy (FTIR). Presence of three-dimensional conductive pathways was confirmed. The obtained percolation thresholds of 2.83 vol.% for PLLA and 3.13 vol.% for PHB composites were measured, which is about three times lower than the ones stated in the literature for similar composites. This property is ascribed to different morphologies of the filler used in the present investigation.
{"title":"Electrical conductivity of poly (L lactic acid) and poly (3-hydroxybutyrate) composites filled with galvanostatically produced copper powder","authors":"Z. Janković, M. Pavlovic, Marijana R. Pantović Pavlović, N. Nikolić, V. Zečević, M. Pavlović","doi":"10.2298/HEMIND180530020J","DOIUrl":"https://doi.org/10.2298/HEMIND180530020J","url":null,"abstract":"This manuscript presents experimental studies of composite materials based on poly (L lactic acid) (PLLA) and poly (3-hydroxybutyrate) (PHB) matrices filled with electrolytic copper powder, having a very high dendritic structure. Volume fractions of the copper powder used as filler in all prepared composites were varied in the range 0.5-6.0 vol.%. Samples were prepared by hot moulding injection at 170 °C. Influence of particle size and morphology, as well as the influence of matrix type on conductivity and percolation threshold of the obtained composites were examined. Characterization included: electrical conductivity measurements using AC impedance spectroscopy (IS), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and Fourier-transform Infrared spectroscopy (FTIR). Presence of three-dimensional conductive pathways was confirmed. The obtained percolation thresholds of 2.83 vol.% for PLLA and 3.13 vol.% for PHB composites were measured, which is about three times lower than the ones stated in the literature for similar composites. This property is ascribed to different morphologies of the filler used in the present investigation.","PeriodicalId":12913,"journal":{"name":"Hemijska Industrija","volume":"72 1","pages":"285-292"},"PeriodicalIF":0.9,"publicationDate":"2018-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43928080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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