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Zaštita Materijala 4. 2015

DRAGAN S. VESELINOVIĆ

Univerzitet U Beogradu, Fakultet za fizičku hemiju, Beograd, Srbija

Pregledni rad
ISSN 0351-9465, E-ISSN 2466-2585
UDC:504.75.03/.06
doi:10.5937/ZasMat1504387V


Zastita Materijala 56 (4)
387 – 396 (2015)

Uzroci zagađivanja životne sredine

Izvod

Planeta Zemlja je naša životna sredina na koju deluju povoljno i nepovoljno hemijske  supstance. Glavni uzroci zagađivanja životne sredine su profit i odsustvo odgovarajućeg znanja. U tekstu se razmatra širenje zagađenja (sa primerima), nastajanje sekundarnih zagađujućih suspstanci i primeri profita kao pokretača zagađivanja životne sredine.

Ključne reči: zagađivanje životne sredine, profit i zagađivanje, znanje i zagađivanje

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The causes of pollution of the enviroment

Abstract

Planet Earth is our enviroment to which we have favorable and unfavorable action of chemical obtained. The main causes of enviromental pollution are profit and the absence od appropriate types of knowledge. The paper discussed the spread of contamination (with examples) secondary creation of pollutants and examples of profit as an engine of enviromental pollution.

Keywords: enviromental pollution, profit and pollution, knowledge and pollution.

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SLAĐANA Č. ALAGIĆ, IVANA RANĐELOVIĆ

Univerzitet U Beogradu, Tehnički fakultet u Boru, Bor, Srbija

Pregledni rad
ISSN 0351-9465, E-ISSN 2466-2585
UDC:332.32/.36:669.3.5(100)
doi:10.5937/ZasMat1504397A
Zastita Materijala 56 (4)
387 – 402 (2015)

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Maksimalno dozvoljene koncentracije esencijalnih metala bakra i cinka u zemljištu, u zakonodavstvima različitih zemalja

Izvod

Toksičnost metala kao što su bakar (Cu) i cink (Zn) prisutnih u zemljištu, nije lako prevideti zbog velikog broja faktora koji utiču na ispoljavanje njihovih toksičnih efekata. Ipak, može se reći da se ovi efekti sve više uvećavaju sa povećanjem sadržaja ovih metala u zemljištima koje pre svega nastaje kao posledica sve izraženijih zagađenja antropogenog porekla. Kako bi se umanjili efekti već nastalih zagađenja (eventualna remedijacija zagađenih terena), ali i prevenirale moguće buduće kontaminacije, mnoge zemlje širom sveta danas uvode propise koji ograničavaju sadržaj čak i esencijalnih elemenata Cu i Zn, ugrađujući u svoja zakonodavstva pre svega one rezultate najnovijih naučnih saznanja i metodologija koji obezbeđuju što tačniji uvid u delovanje različitih koncentracija metala na različite žive organizme i to u različitim zemljišnim uslovima. U ovom radu je dat ne samo pregled podataka za maksimalno dozvoljene koncentracije (MAK) u domaćoj i stranoj legislativi, već su navedeni i objašnjeni svi glavni parametri koji mogu da utiču na stepen ispoljavanja toksičnosti metala u zemljištima.

Ključne reči: bakar, cink, zakonodavstvo, maksimalno dozvoljene koncentracije

 

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Maximum allowable concentrations of essential metals, copper and zinc in the soil, in legislations of different countries

Abstract

It is not so easy to predict the toxicity of metals such as copper (Cu) and zinc (Zn) in the soil, due to the high number of factors which can affect their toxic effects. However, it can be said, that these effects constantly grows with increasing metals contents in soils, which is a common consequence of growing anthropogenic contamination. Nowadays, for the sake of minimization of the present contamination (eventual remediation of contaminated areas) and prevention of any possible contamination in the future, many countries across the World sated some regulations which limit even the contents of essential elements such as Cu and Zn. In their regulations, they incorporated the results of those topical scientific knowledge and methodologies which provide the most accurate insight into the effects of different metal concentrations on different living organisms in the circumstances of different soil conditions. In this paper, a survey of maximum allowable concentrations (MAC) in the domestic and foreign legislative is given, as well as the list of the main parameters which can affect the toxicity of metals in soils.

Keywords: copper, zinc, legislation, maximum allowable concentrations.

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VLADAN MIĆIĆ, MILOVAN JOTANOVIĆ

University of East Sarajevo, Faculty of Technology Zvornik, Zvornik, Republic of Srpska, Bosnia and Herzegovina

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:662.754.2:621.43
doi:10.5937/ZasMat1504403M

Zastita Materijala 56 (4)
403 – 408 (2015)

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Bioethanol as fuel for internal combustion engines

Abstract

The most promising biofuels are bioethanol, biodiesel, pure plant oil, and biomethane. Many biofuels generate large benefits when compared to fossil fuels. The use of bioethanol will largely depend on the potential of available and continuously re-growing biomass, the feedstock sources. Bioethanol produced from renewable feedstock has great potential to reduce greenhouse gasses emissions related to the combustion of fossil fuels. It has chemical and physical properties that are close to fuels from fossil fuels and can be used to exchange petrol in existing engines. Generally bioethanol is expected to have large socio-economic impacts, especially for local actors. Bioethanol production opens new market opportunities for agricultural products and thus new income options for farmers. In the future agriculture will not only play a role in food production, but also in energy provision.

Keywords: biofuel, bioetanol, renewable energy sources, biomass, fossil fuels.

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Bioetanol kao gorivo za motore sa unutrašnjim sagorevanjem

Izvod

Biogoriva za koje se smatra da će biti najperspektivnija u skorijoj budućnosti su bioetanol, biodizel, čisto biljno ulje i biometan. Mnoga biogoriva generišu velike benefite u poređenju sa fosilnim gorivom. Korišćenje bioetanola uglavnom će zavisiti od količine obnovljive biomase kao raspoložive sirovine. Sagorevanjem bioetanola dobijenog iz obnovljivih sirovina dolazi do znatne redukcije gasova koji izazivaju tzv. efekat staklene bašte u poređenju sa sagorevanjem fosilnih goriva. Hemijske i fizičke osobine bioetanola su bliske sa  fosilnim gorivima usled čega on  može biti korišćen da zameni benzin u postojećim motorima. Zbog njegove preferirane proizvodnje i potrošnje očekuje se njegov  veliki društveno ekonomski uticaj naročito na lokalnom nivou. Proizvodnja bioetanola otvara nove tržišne mogućnosti za korišćenje poljoprivrednih produkata i nove šanse za poljoprivredne proizvođače. U budućnosti poljoprivreda neće igrati ulogu samo u proizvodnji hrane već takođe i u obezbeđenju energije.

Ključne riječi: biogorivo, bioetanol, obnovljivi energetski resursi, biomasa, fosilna goriva.

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BRANKA V. KALUĐEROVIĆ, DJURO ČOKEŠA, VLADIMIR DODEVSKI, SANJA KRSTIĆ, VLADISLAVA M. JOVANOVIĆ

University of Belgrade, Institute of Nuclear Sciences Vinča, Belgrade, Serbia, University of Belgrade, ICTM – Department of electrochemistry, Belgrade, Serbia

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:669,218.5:669.238.5(n)
doi:10.5937/ZasMat1504409K

Zastita Materijala 56 (4)
409 – 412 (2015)

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Direct synthesis of noble metal nanostructures on carbon support by hydrothermal process

Abstract

Nanostructures of noble metals (Pt and Ag) on carbon support were prepared from fructose and solution of the Nobel metal salts (H2PtCl6 ´ 6H2O or AgNO3) under hydrothermal conditions. Commercial fructose (C6H12O6) acts as the carbon source and reducing agent and noble metal salts is a source of the metal to be incorporated in the new formed carbon material structure. The crystalline structure was examined by X-ray diffraction (XRD) and morphology investigated by scanning electron microscopy (SEM). The crystallite size of the deposited particles could be estimated by evaluating the line width of the Bragg peak applying the Scherrer method. All the XRD patterns clearly show the five main characteristic peaks of the face-centered cubic (fcc) crystalline for both Pt and Ag crystallite. The obtained Pt crystallite sizes were below 5.5 nm, while the Ag crystallite sizes were about 32 or 34nm.

Keywords: hydrothermal process, platinum, silver, nanostructure, crystallite size.

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Direktna sinteza nanostrukturnog plemenitog metala na ugljeničnoj osnovi pomoću hidrotermalnog procesa

Izvod

Nanostrukture plemenitih metala (Pt i Ag) na ugljeničnom materijalu, kao nosaču, su napravljene, polazeći od fruktoze i rastvora soli plemenitih metala (H2PtCl6 ´ 6H2O ili AgNO3) pri hidrotermalnim uslovima. Komercijalna fruktoza (C6H12O6) deluje kao izvor ugljenika i redukujući agens, a soli plemenitih metala, kao izvor metala, koji treba da se inkorporira u novonastalu strukturu ugljeničnog materijala. Kristalita struktura je ispitivana pomoću difrakcije X-zraka (XRD) a morfologija je ispitivana pomoću skanirajuće elektronske mikroskopije (SEM). Veličina kristalita deponovanih čestica se računa iz širine linije Bragg-ovog pika koristeći Scherrer-ov metod. Svi XRD uzorci jasno pokazuju pet  karakterističnih pikova površinski centrirane kristalne rešetke (fcc) i za kristalite Pt i za kristalite Ag. Dobijeni kristaliti Pt imaju velišinu manju od 5.5 nm, dok su veličine kristalita Ag oko 32 i 34nm.

Ključne riječi: hidrotermalni proces, platina, srebro, nanostruktura, veličina kristalita

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SINIŠA M. VUČENOVIĆ1, DRAGANA RODIĆ2,
JOVAN P. ŠETRAJČIĆ2*

1Univerzitet u Banja Luci, Prirodno-matematički fakultet, Banja Luka, RS – BiH, 2Univerzitet u Novom Sadu, Prirodno-matematički fakultet, Departman za fiziku, Novi Sad, Vojvodina – Srbija

Naučni rad
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.191.5:669.63(n)
doi:10.5937/ZasMat1504413V
Zastita Materijala 56 (4)
409 – 412 (2015)

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Uticaj simetričnih perturbacija na optičke osobine molekulskih nanofilmova

Izvod

U radu su izučavane optičke promjene pod uticajem određenih graničnih uslova u molekulskim kristalnim nanostrukturnim filmovima. U ovome je korišten teorijski model sa prilagođenom metodom Grinovih funkcija i uz pomoć numeričkog proračuna je određen eksitonski zakon disperzije, kao i prostorna distribucija duž graničnih ravni. Pri ovome smo se ograničili na slučaj simetrično perturbovanih uslova, gdje smo pokazali da se osnovne optičke osobine veoma značajno mijenjaju upravo u područjima dejstva perturbacija. Određeni su koeficijenti apsorpcije, refleksije, transparencije i refrakcije na osnovu realnih i imaginarnih dijelova relativne dieletrične permitivnosti. Posebno interesantan rezultat je da ove strukture pokazuju značajan procenat reflektovanog i trensparentnog zračenja u IC-spektru, dok je poznato da balk strukture sačinjene od istih materijala potpuno apsorbuju zračenje u ovom dijelu spektra.

Ključne riječi: tanki filmovi, eksitoni, dielektrična permitivnost, koeficijenti apsorpcije, refleksije, transparencije i refrakcije, Grinove funkcije

 

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Influence of symmetric perturbations on optical properties of molecular nanofilms

Abstract

In this paper we have calculated optical changes under the influence of the boundary conditions in molecular crystalline nanostructured films. We have used theoretical model with the adjusted Greens functions, and using numerical calculations we have calculated dispersion law for excitons, and their spatial distribution along the boundary planes. In this procedure we limited ourselves on case with symmetrically perturbed conditions, and showed that the primary optical properties significantly change just in these planes where perturbations have main influence. We have determined coefficient of absorption, reflection, transparency and refraction on the base of real and imaginary part of the relative dielectric permittivity. Especially interesting case is that those structures show significantly contribution of the reflective and transparent radiation in the IR part of the spectra, while the same material in bulk almost completely absorb radiation in this part of spectra.

Keywords: thin films, excitons, dielectric permittivity, coefficients of absorption, reflection, transparency and refraction, Green’s functions

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VANJA MALIŠIĆ1, DRAGOLJUB ILIĆ2, DRAGOLJUB BEKRIĆ3, MARINA STAMENOVIĆ4, SLAVIŠA PUTIĆ1*

1Univerzitet u Beogradu, Tehnološko-metalurški fakultet, Beograd, Srbija, 2Vazduhoplovna akademija, Beograd, Srbija,  3Univezitet u Beogradu, Mašinski fakultet, Beograd, Srbija, 4VŠSS Beogradska Politehnika, Beograd, Srbija

Naučni rad
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.178.2:666.1-033.5
doi:10.5937/ZasMat1504421M
Zastita Materijala 56 (4)
409 – 412 (2015)

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Mikromehanička analiza loma laminatnog staklo-epoksi kompozitnog materijala ispitivanog na zatezanje

Izvod

Predmet i cilj ovog rada je određivanje statičkih zateznih svojstava staklo-epoksi polimernog kompozitnog materijala. Ispitivani materijal je kompozitni materijal stakleno platno 280 g/m², “twill tkanje“ širine 100 cm, tip – Interglas 92125 i epoksi smola tip MGS L-135, a uzorci su oblikovani ručnom metodom sa 35% zapreminskog udela vlakana. Ispitivane su orijentacije 0/90° i ±45°. Određeni su zatezna čvrstoća i modul elastičnosti prema odgovarajućim standardnim ispitivanjima. Pored izvedene analize dobijenih rezultata, a na osnovu izgleda prelomnih površina uzoraka izvedena je i mikromehanička analiza nastanka i razvoja oštećenja pri zatezanju čime su potvrđeni svi mehanizmi i oštećenja karakteristični za ovakvu vrstu materijala i ispitivanja. Mikromehaničkom analizom na prelomnim površinama ispitivanih uzoraka se došlo do strukture koja je povoljnija u eksploataciji pri ovakvog tipu spoljašnog opterećenja.

Ključne reči: mikromehanička analiza, staklo-epoksi kompozitni materijali, zatezna svojstva staklo-epoksi kompozitnog materijala, ispitivanje na zatezanje staklo-epoksi kompozitnog materijala.

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Micromechanical crack analysis of glass-epoxy laminated composites subjected to tension load

Abstract

The main objective of this study is to determine tensile properties of the glass-epoxy polymer composite material. The material is glass fiber 280 g/m², “twill woven” with 100 cm width, type – Interglas 92125, and epoxy resin type MGS L-135, where samples are molded using hand manual method with 35% fiber weight per volume. Orientations were 0/90° i ±45°. In accordance with appropriate standards, tensile strength and modulus of elasticity were determined. Beside the analysis of the results obtained during the experiment, micro-mechanical analysis of the tensile failure appearance and development was conducted based on the observed cracked surface, which led to a confirmation of all characteristic mechanisms and cracks expected for this type of material and study. Micromechanical analysis performed on the cracked surfaces of the investigated samples, has led to a definition of a structure which is more suitable for exploitation of this material in a presence of this type of external load.

Keywords: micromechanical analysis, glass-epoxy composite materials, tensile properties of glass-epoxy composite materials, tensile test of glass-epoxy composite materials.

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ĐENĐI VAŠTAG1*, JELENA NAKOMČIĆ1, SUZANA APOSTOLOV1, BORKO MATIJEVIĆ1, ABDUL SHABAN2

1Univerzitet u Novom Sadu, Prirodno-matematički fakultet, Novi Sad,Srbija, 2Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary

Naučni rad
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.197.3:669.3
doi:10.5937/ZasMat1504429V
Zastita Materijala 56 (4)
409 – 412 (2015)

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Inhibicija korozije bakra primenom derivata tiazola

Izvod

Primenom elektrohemijske impedansne spektroskopije (EIS) i skenirajućeg elektronskog mikroskopa (SEM) ispitivano je inhibitorsko dejstvo 5-(4’-dimetilaminobenziliden)-2,4-dioksotetrahidro-1,3-tiazola, DABDT, na koroziju bakra u kiselo-sulfatnoj sredini (0,1moldm–3 Na2SO4, pH=3). Dobijeni rezultati ukazuju na dobru inhibitorsku efikasnost ispitivanog derivata, koja raste sa porastom primenjene koncentracije. Zaštitni efekat DABDT-a ostvaruje putem hemisorpcije (prateći Langmirovu izotermu) u obliku vrlo tankog inhibitorskog filma na bakarnu površinu, što se manifestuje povećanjem ukupnog otpora, sniženjem kapaciteta dvojnog sloja, kao i manje oštećenom bakarnom površinom u odnosu na korozionu sredinu.

Ključne reči: korozija bakra, derivat tiazola, EIS, SEM

 

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Inhibition of copper corrosion using thiazole derivative

Abstract

The inhibitor efficiency of 5-(4’-dimetylaminobenzylidene)-2,4-dioxotetrahydro-1,3-thiazole, DABDT, against copper corrosion in acidic sulfate solution (0.1moldm–3 Na2SO4 at pH=3) was investigated applying the electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Obtained results indicated that inhibition efficiency of investigated thiazole derivative is good and that it increases with the increase of the applied concentration of thiazole. The protective effect the DABDT achieved through the adsorption (following Langmuir isotherm) on copper surface as a thin inhibitor film, which is manifested as an increase of the total resistance, a decrease of the double layer capacitance and also as the less damaged copper surface compared with the blank solution.

Keywords: copper corrosion, thiazole derivative, EIS, SEM

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NENAD RISTIĆ, GORDANA TOPLIČIĆ-ĆURČIĆ*, DUŠAN GRDIĆ

University of Niš, Faculty of Civil Engineering and Architecture, Niš, Serbia

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.178.16:666.98
doi:10.5937/ZasMat1504435R

Zastita Materijala 56 (4)
435 – 445 (2015)

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Abrasion  resistance of concrete made with micro fibers and recycled granulated rubber

Abstract

Durability of concrete engineering structures in most part depends on the resistance of their surface to mechanical abrasion. The paper presents the results of experimental test of performance of concretes made with micro fibers and recycled granulated rubber in fresh and hardened state, as well as the comparative analysis of wear grinding resistance and hydro-abrasive resistance of concrete. Six batches of concrete were made for the tests: reference concrete, concrete with partial replacement of fine river aggregate with recycled granulated rubber, two batches with the addition of polypropylene fibers (monofilament and fibrillated) and two batches of concrete with addition of steel hook ended fibers (short – having length 30 mm and long – having length 50 mm). It was found that the addition of micro-reinforcement or recycled rubber contributes to the increase of concrete wear grinding resistance and hydro-abrasive resistance. There is a difference in the abrasive resistance depending on test method.

Keywords: concrete, recycled granulated rubber, polypropylene fibers, steel fibers, wear grinding resistance, hydro-abrasive resistance.

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Abrazivna otpornost betona spravljenog sa mikrovlaknima i recikliranom granulisanom gumom

Izvod

Trajnost betonskih građevinskih konstrukcija u najvećoj meri zavisi od otpornosti njihovih površina prema mehaničkom habanju. U radu su prikazani rezultati eksperimentalnog istraživanja performansi u svežem i očvrslom stanju različitih vrsta betona, kao i uporedna analiza otpornosti prema habanju brušenjem i hidro-abrazivne otpornosti betona.. Za potrebe istraživanja napravljeno je šest serija betona: etalon beton (E), beton sa delimičnom zamenom sitnog rečnog agregata recikliranom granulisanom gumom (ER), dve serije betona sa dodatkom polipropilenskih vlakana (monofilamentnih (EPM)i fibriliranih (EPF)) i dve serije betona sa dodatkom čeličnih vlakana sa ojačanim krajevima (kraća – dužine 30mm (ESS) i duža – dužine  50 mm (ESL)). Utvrđeno je da dodatak mikroarmature ili reciklirane granulisane gume doprinosi povećanju otpornosti betona prema habanju brušenjem i hidro-abrazivne otpornosti. Postoji razlika u otpornosti prema habanju betona u zavisnosti od metode ispitivanja.

Ključne reči: beton, reciklirana granulisana guma, polipropilenska vlakna, čelična vlakna, otpornost prema habanju brušenjem, hidro-abrazivna otpornost

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 ĐURĐA ILIĆ-BAUS1, VLADIMIRKA ILIĆ2*,
MAJA KARAMAN1

1Univerzitet u Novom Sadu, Departman za biologiju i ekologiju, Novi Sad,Srbija, 2Univerzitet u Novom Sadu,  Medicinski Fakultet, Novi Sad,Srbija

Naučni rad
ISSN 0351-9465, E-ISSN 2466-2585
UDC:632.4:669.24/.29
doi:10.5937/ZasMat1504447I
Zastita Materijala 56 (4)
447 – 456 (2015)

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Uticaj Ni, Cu i Cd na brojnost filamentoznih gljiva u zemljištu sa zasadima klonova topole M1, PE19/66 i B229

Izvod

Više od tristotine godina teški metali predstavljaju, pored pesticida u poslednjih pedeset godina, kvantitativno najprisutnije polutante u okruženju. Ukupna koncentracija teških metala u životnom okruženju se ne reflektuje direktno na stepen njihove toksičnosti ili njihove dostupnosti mikroorganizmima, što dodatno otežava tačnu procenu rizika koji sami metali imaju u sredinama u kojima su prisutni. Izuzetno je važno naglasiti uticaj teških metala na antibiotske sposobnosti mikroorganizama.

Tokom eksperimentalnog rada vršeno je ispitavanje uticaja određnih koncentracija Ni, Cu i Cd na brojnost mikroorganizama u zemljištu sa zasadima 3 klona topole. Prema dobijenim eksperimentalnim rezultatima, uticaj Ni, Cu i Cd na brojnost plesni u zemljištu može dovesti to povećanja njihove brojnosti  što se stavlja u blisku korelaciju sa odgovarajućim klonom topole.

Klučne reči: Ni, Cu, Cd, brojnost filamentoznih gljiva, zemljište, topola.

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Influence of a Ni, Cu and Cd on the number of filamentous fungi in soil with poplar sprout clones M1, PE19/66 and B229

Abstract

For more than three hundred years heavy metals in addition to pesticides in the last fifty years, represent quantitatively, the most widespread pollutants in the environment. The total concentrationof heavy metals in the living environment is not reflected directly on the degree of their availability to microorganisms, which further complicates an accurate assessment of the risk that heavy metals have in areas where they are present. It is important to point out influence of heavy metals on antibiotic properties of microorganisms.

During the experimental work the research was carried out examining the impacts of the specified concentrations of NI, Cu, Cd on the number of microorganisms in the soil with 3 clones of poplar plantations. According to the obtained experimental results, the influence of Ni, Cu, Cd on the number of molds in the soil may lead to an increase in their numbers which is placed in close correlation with the corresponding poplar clones.

Keywords: Ni, Cu, Cd, abundance of filamentous fungi, land, Poplar.

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MILAN JAIĆ*, TANJA PALIJA

University of Belgrade, Faculty of Forestry, Department of TMP, Belgrade, Serbia

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.191.5
doi:10.5937/ZasMat1504457J

Zastita Materijala 56 (4)
457 – 462 (2015)

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High gloss finish: the impact of surface roughness on gloss

Abstract

The cured finishes always contain certain irregularities that result from the technique and conditions of application. For this reason, in order to achieve smooth high gloss finished surfaces, it is necessary to polish (“rub-out”) surfaces coated with high gloss finish. Rubbing means sanding the finished surfaces with very fine abrasive grits. In this paper we explored how each phase of the polishing process affect the surface roughness and the gloss of coated surface. The surface roughness was expressed by the parameters: Ra, Rz and Rt, and the gloss was determined by reflectometer (measurement angles 20˚ and 60˚). The results showed that through the stages of polishing, surface roughness decreased, while gloss of finished surface increased. The high value of the coefficient of determination (R2 = 0,984) indicated the linear dependence between the roughness parameter Ra and gloss of finished surface (at measuring angle of 60˚). The comparison of gloss results obtained by two measuring angles, confirmed the need for using the angle of 20˚ when determining the gloss of high gloss surfaces, since universal angle of 60˚ did not provided insight to small differences in the gloss that appeared as a result of polishing.

Keywords: coating, polishing, surface roughness, high gloss.

 

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Premazi visokog sjaja: uricaj hrapavosti površine na sjaj

Izvod

Očvrsnuo film premaza uvek sadrži određene nepravilnosti koje su posledica postupka i uslova nanošenja. Iz tog razloga u cilju postizanja visokog sjaja lakirane površine, uz primenu premaza visokog stepena sjaja neophodno je poliranje lakirane površine tj. brušenje lakirane površine vrlo sitnim brusnim zrnima. U ovom radu ispitano je kako pojedine faze procesa poliranja utiču na hrapavost lakirane površine i stepen sjaja. Hrapavost lakirane površine izražena je parametrima: Ra; Rz i Rt; a sjaj lakirane površine je određen primenom dve geometrije merenja: 20o i 60o.Utvrđeno je da kroz faze poliranja hrapavost lakirane površine opada, a stepen sjaja raste. Visoka vrednost koeficijenta determinacije (R = 0,984) pokazala je da postoji linearna zavisnost između parametra hrapavosti Ra i sjaja lakirane površine (mereno pod uglom od 60o). Primena dve geometrije merenja (20o i 60o) je potvrdila potrebu primene geometrije od 20o kada se određuje sjaj visoko sjajnih površina, jer standardna geometrija od 60˚ ne obezbeđuje sagledavanje malih razlika u stepenu sjaja koje nastaju kao posledica poliranja.

Ključne reči: premaz, poliranje, površinska hrapavost, visoki sjaj.

 

 


NEBOJŠA MARINKOVIĆ1*, KOTARO SASAKI2, MENG LI2, RADOSLAV R. ADŽIĆ2


1
Synchrotron Catalysis Consortium and Columbia University, New York, NY, 2Brookhaven National Laboratory, Upton, NY, USA

Naučni rad
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.179.152
doi:10.5937/ZasMat1504463M


Zastita Materijala 56 (4)
463 – 470 (2015)

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Karakterizacija nanočestica elektrokatalizatora korišćenjem apsorpcione spektroskopije sa X-zracima

Izvod

Apsorpciona spektroskopija sa X-zracima (X-ray absorption Spectroscopy, XAS) je nedestruktivna spektroskopska tehnika koja najčešće koristi sinhrotron kao izvor zračenja, i meri promenu koeficijenta apsorpcije x-zraka uzorka u zavisnosti od energije. Jednistvena snaga tehnike leži u tome što može otkriti unutrašnju strukturu nanočestica, čak i kada je ona sačinjena od više elemenata. Analizom rezultata dobijamo medjuatomska rastojanja i koordinacione brojeve za svaki element, a njihove vrednosti i međusobni odnosi ukazuju da li su elementi u nanočestici u homogenom rastvoru, fizički razdvojeni, ili formiraju jezgro-ljuska (core-shell) česticu u kojoj se jedan broj elemenata pretežno nalaze u sredini, a ostali u ljusci. Ova poslednja vrsta nanočestica je od naročitog značaja za katalizu i elektrokatalizu jer se smanjuje količina plemenitih metala u nanočestici time što se plemeniti metali u jezgru nanočestice zamene jeftinijim. U ovom radu opisujemo način određivanja unutrašnje strukture nanočestica elektrokatalizatora in situ metodom apsorpcione spektroskopije sa X-zracima i dajemo nekoliko primera elektrohemijskih sistema sačinjenih od dva ili tri metala.

Ključne reči: apsorpciona spektroskopija sa X-zracima, EXAFS, XANES, nanokatalizatori, jezgro-ljuska.

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Characterization of nanoparticle electrocatalysts using X-ray absorption spectroscopy

Abstract

X-ray absorption spectroscopy (XAS) is a non-destructive spectroscopic technique commonly used with synchrotron radiation source and measures the changes of absorption coefficient as the function of the x-ray energy. Its unique power is that it can reveal the internal structure of nanoparticles, even if the particle is made up of several elements. By analyzing the results, interatomic distances and coordination numbers for each element are obtained, and their values and relationships indicate whether the elements in the nanoparticle are in a homogeneous solution, physically separated, or form a core-shell particles in which certain elements are mostly located in the core, and the other in the shell. The latter type of nanoparticles is of particular interest for the electrocatalysts as it reduces the precious metal content in the nanoparticles by replacing the precious metal in the the nanoparticles’ core with less expensive alternatives. This paper describes the internal structure characterization of the nanoparticle electrocatalysts by in situ XAS, and gives certain examples of systems composed of two or three metals.

Keywords: X-ray Absorption Spectroscopy, EXAFS, XANES, nanocatalysts, core-shell.

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MIROSLAV M. PAVLOVIĆ1*, VLADAN ĆOSOVIĆ1, JASNA STAJIĆ-TROŠIĆ1, ZORAN JANKOVIĆ2, NEBOJŠA NIKOLIĆ3, MIOMIR G. PAVLOVIĆ3

1Univerzitet u Beogradu, NU IHTM-CMM, Beograd, Srbija, 2V&Z-Zaštita, d.o.o, B. Luka, R. Srpska, 3Univerzitet u Beogradu, NU IHTM-CEH, Beograd, Srbija

Naučni rad
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.193.94:669.054.13
doi: 10.5937/ZasMat1504471P

Zastita Materijala 56 (4)
471 – 482 (2015)

 

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Uticaj morfologije punioca na termijske karakteristike kompozita lignoceluloze punjene metalnim prahovima

Izvod

U ovom radu su prikazani eksperimentalni rezultati istraživanja termijskih svojstava kompozitnih materijala na bazi lignocelulozne matrice (LC) punjenih elektrolitičkim bakarnim prahom i hemijski dobijenim srebrnim prahom. Udeo metalnih punilaca u kompozitnim materijalima u ispitnim uzorcima variran je u opsegu od 1.6-30% (v/v), a uzorci su pripremljeni hladnim presovanjem – kompaktiranjem pri različitim pritiscima. Karakterizacija i ispitivanje uticaja veličine i morfologije čestica na termijske karakteristike dobijenih kompozita. je uključivala različite tehnike ispitivanja: SEM, TGA, DSC, raspodelu veličina čestica i merenja provodnosti. Rezultati termijske analize pripremljenih kompozita pokazuju poboljšanje termalnih karakteristika samih kompozita usled prisustva metalnih punilaca koji su izrazito dobari termički provodnici, tako da se emitovana količina toplote tokom TGA merenja prvobitno akumulira u česticama punioca, pa tek potom dolazi do promene u samoj lignocelulozi. Sa druge strane, nema razlike u odgovoru kompozita sa različitim veličinama i vrstama čestica. Temperatura prelaska u staklasto stanje lignoceluloze kod svih pripremljenih kompozita je povećana za oko 20 ºC.

Ključne reči: termijska analiza, kompozitni materijali, lignoceluloza, DSC, TGA.

 

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The effect of filler morphology on thermal characteristics of lignocellulose and metal powders composites

Abstract

In this manuscript the results of experimental studies of the properties of composite materials based on lignocellulosic matrix (LC) filled with electrolytic copper powder and chemically obtained silver powder are presented. Volume fractions of metal fillers in the composite materials in tested samples were varied in the range of 1.6-30% (v/v), and the samples were prepared by compression – cold pressing. Characterization included examination of the influence of particle size and morphology on the conductivity and percolation threshold of the composites using variety of testing techniques: SEM, TGA, DSC, particle size distribution and conductivity measurements. Thermal analysis of the prepared composites showed the improvement of the thermal characteristics of the composites. This was due to the presence of the metallic fillers which are very good thermal conductors, hence accumulating the emitted heat during TGA measurements primary to lignocellulosic matrix. On the other hand, there is no difference in the response with different metallic fillers and particles with different morphologies. Glass transition temperature is improved by 20 ºC for all the composites.

Keywords: thermal analysis, composite materials, lignocellulose, DSC, TGA

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IVANA POPOVIĆ1, JELENA D. RUSMIROVIĆ2,
MILICA RANČIĆ3, ANA TASIĆ4, DRAGANA LAZIĆ4, ALEKSANDAR D. MARINKOVIĆ1*

1University of Belgrade, Faculty of Technology and Metallurgy, Belgrade,Serbia, 2University of Belgrade, Innovation center, Faculty of Technology and Metallurgy,Belgrade, Serbia, 3University of Belgrade, Faculty of Forestry, Belgrade, Serbia, 4Military Technical Institute, Belgrade, Serbia

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.197.6>620.198
doi:10.5937/ZasMat1504483P
Zastita Materijala 56 (4)
409 – 412 (2015)

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Synthesis of high-performance alkyd anticorrosion coatings based on waste poly(ethylene terephthalate)

Abstract

Synthesis of high-performance anticorrosive coatings obtained from alkyd resins (ARs) based on waste poly(ethylene terephthalate) (PET) glycolyzates is presented. PET glycolyzates, synthesized by catalytic depolymerization with trimethylolpropane (TMP) and dipropylene glycol (DPG), were used as replacement of part of the polyhydroxylic component during the ARs synthesis. The obtained glycolyzates and ARs were analyzed using FT-IR and 1HNMR spectroscopy and acid, iodine, and hydroxyl value were determined. Thickness, adhesion, swelling, corrosion, spraying and layering of the synthesized ARs, as well as alkyd coating film were determined in accordance with SRPS EN ISO standards. ARs were produced in high yields and FT-IR and 1NMR analysis results confirmed assumed structures. All synthesized ARs show good elasticity, flexibility, adhesion and the gloss values are greater than 85 %, and the alkyd coating films based on AR1 and AR3 showed best corrosion results. The most effective dryer catalyst combination was 0.5 wt.% Ca, 0.03 wt.%, Co and 0.45 wt.% Zr.

Keywords: Corrosion, Alkyd anticorrosive coatings, PET based anticorrosive coatings.

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Sinteza visokoefikasnih alkidnih antikorozionih premaza na bazi poli(etilen tereftalata)

Izvod

U radu je prikazana sinteza visokoefikasnih antikorozivnih premaza dobijenih iz alkidnih smola (AR) baziranih na proizvodima glikolize iz otpadnog poli(etilen tereftalata) (PET). Glikolizati PET-a dobijeni postupkom katalitičke depolimerizacije uz pomoć trimetilolpropana (TMP) i dipropilen glikola (DPG), su korišćeni kao zamena polihidroksilne komponente tokom sinteze AR smola. Sintetisani glikolizati i AR smole okarakterisane su primenom FT-IR i 1HNMR spektroskopije i određena im je vrednost kiselinskog, jodnog i hidroksilnog broja. Sintetisanim AR smolama, kao i antikorozionim alkidnim premazima određena su sledeća svojstva: debljina suvog filma, adhezivnost, bubrenje, korozivnost, prskanje i odslojavanje prema SRPS EN ISO standardima. Alkidne smole su dobijene u visokom prinosu i pokazale su dobra fizičko-mehanička svojstva, adhezivnost i sjaj premaza (≤85 %), dok su antikorozioni alkidni premazi na bazi AR1 i AR3 pokazali najbolje rezultate otpornosti na koroziju. Najefikasnija kombinacija katalizatora sušenja je 0.5 mas.% Ca, 0.03 mas.%, Co i 0.45 mas% Zr.

Ključne reči: korozija, alkidni antikorozioni premazi, antikorozioni premazi na bazi PET-a


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M. ALUSHLLARI1*, S. MICO2

1 University of Tirana, Institute of Applied Nuclear Physics, Tirana, Albania, 2 University of Vlore, Department of Physics, Vlore, Albania

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:669.24/.29:628.113(285.2)
doi:10.5937/ZasMat1504492A
Zastita Materijala 56 (4)
492 – 495 (2015)

 

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Analyses of heavy metals in the superfical water of lakes

Abstract

Heavy metal pollution presents a serious problem for human health and ecosystems. During this survey we were collected a total number of 16 surface water samples. The analyses of four heavy metals, Cadmium, Chromium, Copper and Lead, were performed at the Institute of Applied Nuclear Physics, University of Tirana, using Graphite Furnace Atomic Absorption Spectrometry. The current study reports the presence of heavy metals Cd, Cr, Cu and Pb in selected samples. Their concentrations are resulted to be quite low. Average concentrations of metals in the surface water samples were: Pb-2.14µg/L; Cd-0.04 µg/L; Cr-9.44 µg/L; Cu-3.28 µg/L. The concentration of heavy metals in surface water samples is compared with maximum contaminant levels recommended by World Health Organization and Environmental Protection Agency. From the results obtained, none of the analyzed samples contained heavy metals concentrations above the MCL determined from EPA. One of all surface water samples contained the chromium element 6.8% higher than the MCL determined from WHO.

Keywords: heavy metals, surface water, atomic absorption spectrometry.

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Analiza teških metala u površinskim vodama jezera

Izvod

Teška zagađenja metala predstavljaju ozbiljan problem za ljudsko zdravlje i ekosisteme.
Tokom ovog istraživanja sakupljeno je 16 uzoraka površinskih voda jezera. Analize četiri teških metala, kadmijum, hrom, bakar i olovo, izvedena su u Institutu za primenjenu nuklearnu fiziku, Univerziteta u Tirani, koristeći grafitnu peć za atomsku spektrometrijom.

Rezultati ispitivanja su pokazali prisustvo teških metala Cd, Cr, Cu i Pb u odabranim uzorcima. Njihove koncentracije su bile prilično niske. Prosečne koncentracije metala u uzorcima površinske vode bili su: Pb – 2.14mg / L ; Cd- 0.04 ug / L ; Cr- 9.44 ug / L ; Cu- 3.28 ug / L . Koncentracija teških metala u uzorcima površinskih voda je u poređenju sa maksimalnim nivoima zagađivača voda preporučenih od strane Svetske zdravstvene organizacije i Agencija za zaštitu životne sredine. Od dobijenih rezultata, nijedan od analiziranih uzoraka ne sadrži koncentracije teških metala iznad MCL određene iz EPA. Jedino je jedan od svih uzoraka površinskih voda sadržala hroma 6,8% sto je vise u odnosu na MCL određen od SZO.

Ključne reci: teški metali, površinske vode, atomska apsorpciona spektrometrija.

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MILORAD V. TOMIĆ1*, VLADAN MIĆIĆ1, MIOMIR G. PAVLOVIĆ1, MIROSLAV M. PAVLOVIĆ2, GORAN BOŠKOVIĆ3, NEBOJŠA D. NIKOLIĆ4

1University of East Sarajevo, Faculty of Technology Zvornik,Zvornik, Republic of Srpska, 2University of Belgrade, ICTM – CMM, Belgrade, Serbia, 3University of Novi Sad, Faculty of Technology, Novi Sad, Serbia, 4University of Belgrade, ICTM – Center of Electrochemistry, Belgrade, Serbia

Naučni rad
ISSN 0351-9465, E-ISSN 2466-2585
UDC:661.25.097.8:669.3-492.2
doi:10.5937/ZasMat1504496T

Zastita Materijala 56 (4)
496 – 504 (2015)

 

Katalitičko delovanje sumporne kiseline na morfologiju elektrohemijski dobijenog bakarnog praha

Izvod

Predmet istraživanja je uticaj sumporne kiseline na morfologiju elektrohemijski dobijenog bakarnog praha pri galvanostatskom režimu elektrolize. U ovom radu je vršeno elektrohemijsko taloženje bakarnog praha iz sulfatnih elektrolita. Korišćeni su elektroliti sa tri koncentracije Cu2+ (7 g/dm3, 18 g/dm3 i 33 g/dm3) i svaka u kombinaciji sa tri koncentracije H2SO4 (100 g/dm3, 150 g/dm3 i 200 g/dm3), tako da je bakarni prah taložen iz devet elektrolita. Kao katoda je korišćena bakarna žica površine 1cm2, a bakarna anoda u obliku lima je bila priljubljena uz zid elektrohemijske ćelije, zapremine 500 cm³. Eksperimenti su izvođeni na sobnoj temperaturi, a mešanje elektrolita vršeno je pomoću magnetne mešalice. Bakarni prah taložen je galvanostatski pri gustinama struje od: j=1500 A/m2, j=2000 A/m2 i j=2500 A/m2. Proizvedeni bakarni prah je uklanjan sa katode svaka tri minuta. Sve osobine praha zavise od oblika i dimenzija čestica (morfologije) i međusobno su povezane. Ispitivanje morfologije i veličine čestica vršeno je pomoću skenirajuće elektronske mikroskopije (SEM). Sa povećanjem koncentracije H2SO4, povećava se i razgranatost bakarnog praha. Utvrđeno je da se veličina čestica smanjuje sa povećanjem koncentracije H2SO4.

Ključne reči: elektrohemijsko taloženje, prah bakra, morfologija, kataliza

 

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Catalytic activity of sulfuric acid on the morphology of electrochemically obtained copper powder

Abstract

The subject of the research is influence of sulfuric acid on morphology of electrochemically obtained copper powder during galvanostatic electrolysis mode. In this paper electrodeposition of copper powder from sulphate electrolyte was carried out. Electrolytes with three different concentrations of Cu2+ (7 g/dm3, 18 g/dm3 and 33 g/dm3) were used, each in combination with three different concentrations of H2SO4 (100 g/dm3, 150 g/dm3 and 200 g/dm3), so that copper powder was deposited from nine electrolytes. Copper wire with surface area of 1cm2 was used as cathode, and copper anode in the form of metal sheet was pressed against the wall of electrochemical cell that had volume of 500 cm³. Experiments were carried out at room temperature, and electrolyte stirring was performed using a magnetic stirrer. Copper powder was deposited galvanostatically at current densities of j = 1500 A/m2, j=2000 A/m2 and j=2500 A/m2. Produced copper powder was removed from cathode every three minutes. All the characteristics of powder depend on the size and shape (morphology) of particles and they are mutually correlated. Research of morphology and size of particle was carried out using scanning electron microscopy (SEM). Increase of H2SO4 concentration causes increase in branching of copper powder. It was concluded that the size of copper powder grains reduces with the increase in concentration of H2SO4.

Keywords: electrodeposition, copper powder, morphology, catalysis


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MILENA ĆOSIĆ1*, MARINA DOJČINOVIĆ2,
SLOBODANKA BOLJANOVIĆ3
1Tehnikum Taurunum, College of Mechanical Engineering, Belgrade,Serbia, 2University of Belgrade, Faculty of Technology and Metallurgy, Belgrade,Serbia, 3Military Technical Institute, Belgrade,Serbia

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.183:669.715
doi:10.5937/ZasMat1504505C

Zastita Materijala 56 (4)
505 – 509 (2015)

 

Influence of the structural changes on cavitation resistance of Al18SiCuMg alloy produced by rheocasting process

Abstract

The influence of stirring speeds of 1000 and 1500 r/min on the microstructure of Al18SiCuMg alloy was investigated. The smaller size of Si particles of rheocast sample obtained by higher cooling rate and higher stirring speed was achieved. According to the results of cavitation test, the cavitation rate of the rheocast sample produced by 1500 r/minis lower than that of the rheocast sample obtained by 1000 r/min. The different results show that the mass loss as a function of time can be approximated either by liner or quadratic equations.

Keywords: Al18SiCuMg alloy, rheocasting, microstructure, cavitation rate.

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Uticaj strukturnih promena na kavitacionu otpornost Al18SiCuMg legure proizvedene reokasting procesom

Izvod

U radu je ispitivan uticaj brzine mešanja od 1000 i 1500 obrta/min na mikrostrukturu Al18SiCuMg legure. Manja veličina Si čestica u reokast uzorcima postignuta je pri većoj brzini hlađenja i većoj brzini mešanja. Prema rezultatima kavitacionog ispitivanja, kavitaciona brzina reokast uzoraka dobijenih pri brzini mešanja od 1500 obrta/min je niža u odnosu na reokast uzorke dobijene pri brzini mešanja od 1000 obrta/min. Rezultati ispitivanja pokazuju da se gubitak mase u funkciji vremena može aproksimirati ili pomoću linearnih ili kvadratnih jednačina.

Ključne reči: Al18SiCuMg legure, reokasting, mikrostruktura, kavitaciona brzina.


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MILOŠ B. RAJKOVIĆ1*, IVANA SREDOVIĆ IGNJATOVIĆ1, LJUBIŠA IGNJATOVIĆ2, VIKTOR NEDOVIĆ1, SLOBODAN PRIJIĆ1

1Univerzitet u Beogradu, Poljoprivredni fakultet, Beograd,Srbija
2 Univerzitet u Beogradu, Fakultet za fizičku hemiju, Beograd, Srbija

Naučni rad
ISSN 0351-9465, E-ISSN 2466-2585
UDC:543.544.1:663.4
doi:10.5937/ZasMat1504510R
Zastita Materijala 56 (4)
510 – 521 (2015)

 

Određivanje katjona i metala u pivu i sirovinama za proizvodnju piva metodama jonske hromatografije (IC) i atomske apsorpcione spektrofotometrije (AAS)

Izvod

U cilju kontrole kvaliteta piva i sirovina za proizvodnju piva u Beogradskoj industriji piva (BIP) primenjene su metode jonske hromatografije (IC) i atomske apsorpcione spektrofotometrije (AAS). Od sirovina za proizvodnju piva analizirana je voda (gradska, tehnološka i demineralizovana). Merenja pH vrednosti ukazala su na povećanu pH vrednost u uzorku tehnološke vode, ali to nije imalo uticaj na ukomljavanje slada pošto su ispitivani uzorci sladovine, kao i uzorci mladog piva i gotovog proizvoda imali pH vrednost u očekivanom opsegu. Analiza sadržaja anjona i katjona u ispitivanim uzorcima vode, pokazala je da je koncentracija ispitivanih anjona (Cl, NO3, SO42– i PO43–) i katjona (NH4+, Na+, K+, Ca2+, Mg2+), kao i mikroelemenata (Fe, Cu i Zn) u granicama propisanim Pravilnikom o higijenskoj ispravnosti vode za piće i Pravilnikom o kvalitetu i drugim zahtevima za pivo. Ispitivanje sadržaja anjona u uzorcima sladovine i piva (mladog i gotovog proizvoda) pokazalo je da je sadržaj SO42–– i NO3-jona bio u preporučenim granicama, koncentracija Cl-jona bila je iznad 150 mg/dm3, što može imati uticaj na senzorne karakteristike piva, dok je promena sadržaja PO43–-jona bila neznatna. Pošto je AAS standardna metoda za analizu sadržaja alkalnih i zemnoalkalnih metala, rezultati dobijeni ovom metodom u uzorcima piva uzeti su kao referentni i prema njima je izvršena analiza i upoređivanje rezultata dobijenih metodom IC. Rezultati određivanja Na, Ca i Mg u ispitivanim uzorcima vode, pokazala su odstupanja, ali su obe metode ukazale na povećan sadržaj natrijuma u demineralizovanoj vodi. Sadržaj alkalnih i zemnoalkalnih metala u uzorcima sladovine i piva (mladog i gotovog proizvoda) ukazao je da su rezultati dobijeni ovim dvema metodama bili u saglasnosti.

Ključne reči: pivo, jonska hromatografija, atomska apsorpciona spektrofotometrija, teški metali

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Determination of Cations and Metals in Samples of Beer and Raw Materials for Beer Production by Ion Chromatography (IC) and Atomic Absorption Spectrophotometry (AAS) Methods

Abstract

In order to control the quality of beer and raw materials for beer production, methods as ion chromatography (IC) and atomic absorption spectrophotometry (AAS) were applied. Water was analyzed as a raw material for beer production (urban, technological and demineralized water). Measurements of pH values indicated the increased pH values in the sample of tehnological water, but it had no impact on wort hopping, since the tested samples of wort, young beer and final product had a pH value in the expected range. Analyzing the content of anions and cations in the examinated water samples, it is shown that the concentration of these examinated anions (Cl–, NO3–, SO42– and PO43–) and cations (NH4+, Na+, K+, Ca2+, Mg2+), as and microelements (Fe, Cu i Zn) are within the limits prescribed by the Regulations on hygienic safety of drinking water and the Regulations of quality and other requirements for beer. Investigating contents of anions in samples of wort and beer (young beer and final product) showed that the contents of SO42- and NO3– ions were within recommended limits and the concentration of Cl– ions was above 150 mg/dm3, which may have an impact on sensory characteristics of beer, while changes in the content of PO43– ions were insignificant. Since AAS method is a standard method for analyzing content of alkaline and alkaline earth metals, the results obtained by this method in beer samples are taken as a referent results and according to them an analyse was performed and results obtained by IC method were compared. Results of the determination of Na, Ca and Mg in examinated water samples have shown variations, but both methods have shown the increased content of Na in demineralized water. The contents of alkaline and alkaline earth metals in wort and beer (young beer and final product) have shown that the results obtained by these two methods were in agreement.

Keywords: beer, ion chromatography, atomic absorpion spectrophotometry, heavy metals


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ZORAN JANKOVIĆ1 , BOSILJKA LjUBIČIĆ1
SAŠA MIĆIN2

1“V&Z-zaštita“ d.o.o., Banja Luka, Republika Srpska, 2“Ekvator“d.o.o., Banja Luka, Republika Srpska

Naučni rad
ISSN 0351-9465,
E-ISSN 2466-2585
UDC: 620.197.3
doi: 10.5937/ZasMat1504522J

Zastita Materijala 56 (4)
522 – 526 (2015)

 

Uloga i mehanizam dejstva inhibitora u rastvorima za nagrizanje čelika

IZVOD

Kiselo nagrizanje (bajcovanje) ima osnovni zadatak, bez obzira koja se kiselina upotrebljavala, da ukine korozione produkte sa predmeta prije nego što počne da nagriza osnovni materijal. Dejstvo kiseline na osnovni materijal izaziva gubitak metala i kiseline kao i nastajanje grešaka kod bajcovanja. Da bi se spriječilo ovo neželjeno sporedno dejstvo u rastvor za nagrizanje dodaje se inhibitor. U ovom radu testirali smo inhibitorsko dejstvo tri različita neorganska inhibitora u rastvoru HCl i H2SO4 i jednog organskog inhibitora u rastvoru H3PO4 u procesu bajcovanja cunderisanog čelika. Istraživanje je provedeno upotrebom gravimetrijske metode. Dobijeni rezultati ukazuju na zaštitnu vrijednost inhibitora preko 98% u svim testiranim koncentracijama HCl i H2SO4, dok je inhibitorsko dejstvo organskog inhibitora u rastvoru H3PO4 pri temperaturi od 60ºC izostalo.

Ključne riječi: bajcovanje, inhibitor, čelik, zaštitna vrijednost inhibitora.

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The role and action mechanism of inhibitors in solutions for etching steel

ABSTRACT

Acid etching has a major task, regardless of which acid is used, to cancel all corrosion products from objects before it starts to erode  base material. The effect of acid on base material causes metal and acid loss, as well as formation of etching defects. In order to prevent this undesired side effect, inhibitor is added in etching solution. In this paper we tested the inhibitory effect of three different inorganic inhibitors in HCl and H2SO4 solutions and one organic inhibitor in H3PO4 solution in the process of etching rust steel. The research was conducted using gravimetric method. Obtained results indicate protective value of inhibitor in over 98 % in all tested concentrations of HCl and H2SO4, while the inhibitory effect of organic inhibitor in H3PO4 solution at the temperture of 60ºC was absent.

Keywords: etching, inhibitor, steel, protective value of inhibitor

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