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Zaštita materijala 2. 2012

 

GABER EL-ENANY

Scientific paper [PDF]
UDC:623.3.035.2’036.8

Supercapacitive properties of Electropolymerized Poly(3,4-ethylene dioxythiophene) and Poly(aniline) Co-polymer electrodes

In this paper a co-polymer of polyaniline (PANI) and Poly(3,4-ethylenedioxythiophene) PEDOT films with different molar ratio (MR) were electrochemically deposited by cyclic voltammetry and short current pulse onto glassy carbon electrode from micellar solution. The surface morphology of the resulting co-polymer films was characterised by scanning electron microscope and the effect of monomers molar ratios on capacitive property were characterised using cyclic voltammetry in acidic and neutral solutions. The specific capacitance of the PEDOT-PANI co-polymer reaches up to 327 F g−1 and retains about 90% from original value after 300 cycles in 1.0 M H2SO4 at 10 mVs−1. Presence of sodium dodoceyl sulphate (SDS) enhanced the co-polymer capacitance and decreased the polymerization potential of the monomers. The polymer composites show improved capacitance stability in neutral solution (1.0 M NaCl) as well as in acidic solution which reflects the synergism between PANI and PEDOT of the co-polymer deposit.

Key words: Conducting polymers; Electron microscopy; Electrochemical properties; Supercapacitor.

 

SUPERKAPACITIVNA SVOJSTVA ELEKTROPOLIMERIZOVANIH POLI(3,4-ETILENDIOKSIFENE) I POLI(ANILIN) Co-POLIMERSKIH ELEKTRODA

U ovom radu ko-polimer od polianilina (PANI) i poli (3,4-etilendioksitofen) PEDOT filmovi sa različitim molarnim odnosom (MR) su elektrohemijski deponovani putem ciklične voltametrijei struja kratkog impulsana elektrodi od staklastog micelarnog ugljenika.

Morfologija površina nastalih ko-polimernih filmova karakterisana je elektronskim mikroskopom a efekat molarnog monomera ispitan je korišćenjem ciklične voltametrije u kiselim i neutralnim rastvorima. Specifična kapacitivnost PEDOT-PANI ko-polimera dostiže i do 327F g-1 i zadržava oko 90% od osnovne vrednosti posle 300 ciklusa u 1M H2SO4 na 10 mVs-1. Prisustvo natrijum dodecil sulfata (SDS) poboljšava kapacitivnost polimera i smanjuje potencijal polarizacije monomera. Kompozitni polimeri pokazuju poboljšanu kapacitivnu stabilnost u neutralnom rastvoru 1M NaCl, kao i u kiselom rastvoru koji odražava sinergizam između PANI i PEDOT na depozitu ko-polimera.

Key words: polimer, elektronska mikroskopija, superkapacitivnost, elektrohemijska ispitivanja.

 


 

MAJLINDA HYLLI 1, GENTI GUXHOSPIRO DRUSHKU3

Scientific paper [PDF] 
UDC:615.1.017.4/.6(497.5)

Determination of some chemical and physico – mechanical indicators of Albanian leather

This study is focused in measuring some chemical and physico- mechanical indicators like untanning, determination of humidity, pH, thickness, determination of leather side resistance along flexing, determination of tensile strength and percentage elongation in different Albanian leathers. Leather industry is one of the most important. Leather is one of the last remaining natyral materials in our high- tech world of teflon, rubber and synthetic materials. For this reason, leather is one of the most important and usable materials in various fields. Leather processing from row skin/hide up to end product passes through several stages. In order to obtain such a versatile end product from a simple animal skin, this material has to be subjected to numerous processes, which are: preservation, soaking, liming, tanning and finishing. Each of these processes play a decisive role in giving and preserving important leather characteristics to the end product. Control of each of these processes is very important to avoid defects that can arise during these leather processing, as well as to make it more stable against of swell, decay, action of high temperatures, action of microorganisms (microbes and enzymes) etc. We did chemical and physico-mechanical analysis according ISO standarts. Selection of tests samples is done in a random way. Evaluation of some of these indicators is done according to www.ctlleather.com/ctl_clearance_products in the absence of technical specifications .

Key words: leather, ISO standarts, chemical and physico-mechanical characteristics.

 

ODREĐIVANJE NEKIH HEMIJSKIH I FIZIČKO-MEHANIČKIH KARAKTERISTIKA KOŽE

Ovaj rad se fokusira na merenju nekih hemijskih i fiziko-mehaničkih pokazatelja kao što su određivanje vlažnosti, pH, debljina, određivanje otpora opuštanja kože, određivanje zatezne čvrstoće i procenta istezanja u različitim vrstama albanske kože. Industrija kože je jedna od veoma važnih. Koža je jedna od preostalih prirodnih materijala u svetu teflona, gume i sintetičkih materijala. Iz tih razloga, koža je jedna od najvažnijih i upotrebljavanih materijala u raznim oblastima. Prilikom obrade kože prolazi se kroz nekoliko faza. Da bi se dobio praktičan proizvod polazeći od životinjske kože, ovaj materijal mora da bude podvrgnut brojnim procesima, koji su: čuvanje, potapanje, liming, štavljanje i dorada. Svaki od ovih procesa igra odlučujuću ulogu u davanju i očuvanju važnih karakteristika kože do krajnjeg proizvoda. Kontrola svakog od ovih procesa je veoma važna kako bi se izbegli nedostaci koji mogu nastati tokom ovih obrada kože, kao i da bi se stabilizovalo dejstvo visokih temperatura, mikroorganizama, itd. Urađena su hemijska i fizičko-mehanička ispitivanja prema ISO standarima. Izbor uzorka je vršen po slučajnom tipu. Procena nekih od ovih indikatora vršena je prema tehničkoj specifikaciji.

Key words: koža, ISO standardi, hemijska i fizičko-mehaničke karakterstike.

 


 

S. JOHN MARYS. RAJENDRAN2

Scientific paper [PDF]
UDC:616.15’78:620.193.4

Corrosion behaviour of metals in artificial blood plasma in presence of glucose

Electrochemical behavior of seven metals namely, mild steel, (super elastic) Ni, Ti, Ni-Cr, SS316, Cu-Ni-Ti, 22 Carat gold, 24 Carat gold have been evaluated in artificial plasma in presence of glucose. Pontentiodynamic polarizations study and AC impedance spectra have been used to investigate the corrosion behavior of these metals. Among these seven metals SS316 and Ni-Cr are showing very good corrosion resistance. Rest of the metals shows good corrosion resistance when very small amount of glucose is present. Generally for diabetes the glucose level is not stable. Glucose level will increase or decrease. For them some metallic materials are used as implants in reconstructive surgery to replace bones or joining of bones. The metals may contact the blood during the blood circulation when human blood is circulate the diabetes body the implant metals such as mild steel, super elastic, Ni- Cr, SS316, Cu Ni-Ti, 22 Carat gold and 24 Carat gold even in presence of glucose also control the corrosion resistance. The metals such as SS316 and Ni-Cr are showing very good corrosion resistance even in presence of 0.05 g amount of glucose. Electrochemical studies were carried out in a CHI –Electrochemical workstation with impedance, model 660A. The instrument was used for polarization study and to record AC impedance spectra. The cell setup was also the same. The real part (Z’) and imaginary part (Z”) of the cell impedance were measured in ohms at various frequencies.

Key words: Corrosion, artificial plasma, SS316L, Ni-Cr, glucose

KOROZIONO PONAŠANJE METALA U VEŠTAČKOJ KRVNOJ PLAZMI U PRISUSTVU GLUKOZE

Elektrohemijsko ponašanje nekih metala i legura (meki čelik), Ni, Ti, Ni-Cr, SS316, Cu-Ni-Ti, 22 i 24-karatno zlato je bilo ispitano u veštačkoj plazmi u prisustvu glukoze. Potenciodinamičko polarizaciono ispitivanje i AC impedancijski spektri su bili korišćeni da se istraži koroziono ponašanje ovih metala i legura. Medju njima, SS316 i Ni-Cr pokazuju veoma dobro korozionu otpornost. Ostatak metala i legura pokazuje dobru korozionu otpornost kada veoma mala količina glukoze je prisutna.

Ključne reči: korozija, veštačka plazma, SS316L, Ni-Cr, glukoza

 


 

DEJAN SMOLOVIĆMIRA VUKČEVIĆ2, DRAGOLJUB BLEČIĆ2

Originalni naučni rad [PDF]
UDC:669.712.1

Uticaj gustine i temperature razblažene suspenzije kao i vrste rastvora u kome se priprema emulzioni flokulant na brzinu taloženja crvenog mulja i kvaliet aluminatnog rastvora

Ovaj rad predstavlja nastavak industrijskih istraživanja primjene emulzionog flokulanta (hidroksa­matnog poliakrilamida -HX 300), koja su obuhvatala praćenje brzine taloženja crvenog mulja sa postojećim flokulantima i brzine taloženja sa emulzionim flokulantom, kao i karakteristike istaloženog crvenog mulja sa stanovišta granulacije i sadržaja suvih materija dobijenih nakon primjene gore navedenih flokulanata. U ovom radu istraživanja su imala za cilj da se na bazi eksperementalnih re­zultata, utvrde efekti pripreme emulzionog flokulanta u različitim rastvorima, kao i uticaj temperature i gustine razblažene suspenzije u koju se dodaje emulzioni flokulant na efekte taloženja crvenog mulja. Dobijeni rezultati pokazuju da priprema emulzionog flokulanta HX 300 u alkalnim rastvorima daje znatno bolje rezultate u pogledu brzine taloženja crvenog mulja i bistroće preliva (rastvora aluminata) u odnosu na pripremu istog flokulanta u industrijskoj vodi. Sa povećanjem temperature razblažene suspenzije u kojoj se dodaje emulzioni flokulant HX 300, povećava se brzina taloženja crvenog mulja i poboljšava kvalitet (bistroća) aluminatnog rastvora, dok povećanje gustine razblažene suspenzije u koju se dodaje emulzioni flokulant negativno utiče na efekte taloženja crvenog mulja. Takođe sa povećanjem razblaženja suspenzije nakon procesa luženja boksita u kojoj se dodaje emulzioni flokulant HX 300, povećava se brzina taloženja crvenog mulja i pobojlšava kvalitet (bistroća) aluminatnog rastvora.

Ključne riječi: crveni mulj, flokulant, taloženje, aluminatni rastvor

 

THE INFLUENCE OF DENSITY , TEMPERATURE AND TYPE OF LUQVID IN WHICH PREPARATION EMULSION FLOCCULANT ON RED MUD SETTLING VELOCITY AND ALUMINATE QUALITY LIQUOR

This work represents a continuation of the industrial application of research emulsive flocculants (hydroxamate polyacrylamide –HX 300 )that included monitoring the sedimentation velocity with the existing red mud flocculants and the sedimentation velocity as well as the characteristics of red mud in terms of granulation and content of dry substances obtained after applying the above flocculants In this work the investigation is defining of the effects of emulsion flocculants preparation in different solutions. The influence of temperature and density of diluted solution as the medium for flocculants adding on red mud settlement have also been investigated. The results indicate better effects in terms of settlement velocity as well as clarity when the emulsion flocculants HX300 has been used in comparison with the effects of flocculants prepared in industrial water. Increasing of diluted suspension temperature with the flocculants HX300 the red mud settlement velocity has been increased. The clarity of aluminate solution was of the better quality. Increasing of the diluted suspension density has the negative effect on red mud settlement effects. The increased dilution of the suspension after the bauxite leaching (with the HX300 flocculants) increases the red mud settlement velocity and influence the better quality of aluminate solution in terms of quality.

Key words: red mud, flocculants, settlement, aluminate solution

 


 

MIRJANA JOVIČIĆ, RADMILA RADIČEVIĆ, JELENA PAVLIČEVIĆ, OSKAR BERA, IVAN RISTIĆ

Originalni naučni rad [PDF]
UDC:667.621.632

Svojstva umreženih filmova alkidnih premaza modifikovanih heksametoksimetil melaminskom smolom

Sintetisane su alkidne smole na osnovu anhidrida ftalne kiseline, ricinolne kiseline i tri različita poliola: glicerina, trimetilolpropana i etoksilovanog pentaeritritola. Sadržaj ricinolne kiseline kod svih sintetisanih alkida je iznosio 30 mas. %. Alkidne smole su umešavane sa komercijalnom heksametoksimetil melaminskom smolom u masenom odnosu čvrstih smola 70:30. Nakon homogenizovanja smeše su razlivene u vidu filmova, a potom umrežavane sat vremena u sušnici na temperaturi od 150 °C. Dinamičko mehaničkom analizom praćene su zavisnosti modula sačuvane energije, modula izgubljene energije i tangensa ugla mehaničkih gubitaka od temperature, iz kojih su određene temperature prelaska u staklasto stanje, kao i gustine umreženosti filmova. Ispitana su sledeća svojstva umreženog filma premaza: debljina, prianjanje, sjaj, tvrdoća, elastičnost, otpornost na udar i otpornost na metiletilketon. Na osnovu dobijenih rezultata može se zaključiti da svi filmovi premaza imaju zadovoljavajuće vrednosti ispitivanih svojstava, što je posledica velike gustine umreženosti.

Ključne reči: alkidna smola, heksametoksimetil melaminska smola, dinamičko mehanička analiza, svojstva umreženog filma premaza

 

Properties of cured films based on alkyd resins modified with hexamethoxymethyl melamine resin

Three alkyd resins based on ricinoleic acid (30 wt. %), phthalic anhydride and three polyols (glycerin, trimethylolpropane or ethoxylated pentaerythritol) were synthesized. Baking enamels were prepared by mixing the synthesized alkyds with commercial hexamethoxymethyl melamine resin (weight ratio of 70:30 based on dried mass). After the homogenization at room temperature, a thin layer of the resin mixture was applied on a glass panel. Curing of coating films was performed in an oven at 150 °C for 1 h. Dynamic mechanical analysis (DMA) was used to determine glass transition temperature of cured films. The values of the storage modulus, loss modulus and loss tangent were determined in temperature range from −30 to 120 °C. According to the height of the storage modulus rubbery plateau, it is possible to obtain the crosslink density of cured resin mixtures. The film properties (thicknesses, adhesion, gloss, hardness, flexibility, impact resistance and methyl ethyl ketone resistance) were also investigated. The mixtures of synthesized alkyds resins and commercial hexamethoxymethyl melamine resin (weight ratio 70:30) could be successfully used as baking enamels.

Key words: alkyd resin, melamine resin heksametoksimetil, dynamic mechanical analysis, the properties of crosslinked film coating

 


 

Z. JANJUŠEVIĆ1, Z. GULIŠIJAM. MIHAILOVIĆ1, A.PATARIĆZ. KARASTOJKOVIĆ2, Z. KOVAČEVIĆ3

Originalni naučni rad [PDF]
UDC:621,742.45.043

Uticaj dodavanja aktivnih komponenti kalupnoj mešavini na površinu odlivaka

Od vrste i kvaliteta kalupne mešavine odnosno njenog ponašanja u dodiru sa stopljenim metalom u realnim uslovima najviše zavise intenzitet, i uopšte razvoj, pojedinih procesa na graničnoj površini dodira metal-kalup. Značajno mesto u odigravanju procesa međusobnog delovanja livačkih kalupa i tečnog metala pored hemijskog, mineralnog sastava peska, vrste vezivnog sredstva imaju i dodaci kalupnim mešavinama. Ovi dodaci, tj aktivne komponente, uslovljavaju određene promene na povišenim temperaturama u samoj mešavini kao i njeno reagovanje sa površinskim slojem tečnog metala. Cilj ispitivanja je bio da se vidi u kolikoj meri sastav kalupne mešavine sa i bez dodatih-aktivnih komponenata utiče na površinu odlivaka.

Ključne reči: odlivak, površina, livenje, kalup, pesak, dodaci

 

Influence of aCitive components ADDITION to mould mixture on the castings surface

The intensity, and overall development of individual process on the metal-mould interface depend on the type and quality of mould mixture or its behaviour in contact with the melted metal in real conditions. Important role in interaction between foundry moulds and liquid metals, in addition to chemical and mineral composition of sand, and a type of binding material, play also additives for mould mixtures. These additives, i.e. active components, provided some changes at elevated temperatures inside the mixture, as well as its reaction with the surface layer of liquid metal. The aim of this investigation was to determine how the composition of the mould mixture with and without active components affect the surface of castings.

Key words: casting, surface, foundry, mould, additives

 


 

O. ŠUPIĆ1, B. ĐUKIĆ2

Originalni naučni rad [PDF]
UDC:669.58

Analiza uticaja sadržaja Si u čeliku, temperature rastopa cinka i vremena uranjanja na debljinu prevlake cinka

Klimatski uslovi i zagađenost atmosfere sve više uslovljavaju potrebu dugoročne zaštite čeličnih konstrukcija. Za zaštitu čelika u atmosferskim uslovima kao najefikasnija se pokazala zaštita prevla­kom cinka,  dobijenom uranjanjem u ratstop cinka pri temperaturalnom intervalu od 435 0C – 470 0C. Na debljinu prevlake cinka bitno utiče sastav čelika a naročito sadržaj Si, zatim temperatura rastopljenog cinka i dužina vremena zadržavanja predmeta u rastopu cinka. Cilj ovog rada je da koristeći stručnu literaturu i neke rezultate sopstvenih ispitivanja, prikaže međuzavisnost debljine sloja cinka i izabranih tehnoloških parametara.

Ključne reči: čelik, prevlaka cinka, tehnološki parametri procesa

 

THE ANALYSIS OF THE EFFECT OF Si CONTENT IN STEEL, MELTING TEMPERATURES OF ZINC AND THE TIME OF IMMERSION ON THE ZINC COATING THICKNESS

Climatic conditions and the atmospheric pollution bring about the ever increasing need of long-term protection of steel structures. Zinc coating protection, done by immersion into zinc solution in the temperature interval between 4350 C and 4700C, has proved to be the most efficient way for protecting the steel in atmospheric conditions. Steel composition, particularly the content of Si, as well as the temperature of molten zinc and the time the object has been immersed in the zinc solution, significantly affect the thickness of zinc coating. The aim of this work is to show the interdependence of the zinc layer thickness and the chosen technological parameters, by using scientific literature and the results of our own research.

Key words: steel, zinc coating, parameters of the technological process

 


SNEŽANA DIDANOVIĆ, GORAN SEKULIĆ

Stručni rad [PDF]
UDC:628.357.4(497.16)

Biljke u procesu prečišćavanja otpadnih voda u Crnoj Gori

Ovaj rad ispituje mogućnost primjene fitodepuracije, kao jednog od načina prečišćavanja otpadnih voda u Crnoj Gori. U uvodnom dijelu dat je kratak istorijat upravljanja otpadnim vodama, sa naglaskom na analizu stanja upravljanja otpadnim vodama u Crnoj Gori, kao i evropsku i domaću zakonsku regulativu u ovoj oblasti. Takođe, u ovom dijelu date su i karakteristike otpadnih voda i metode prčišćavanja otpadnih voda koje su analizirane u strateškim dokumentima u Crnoj Gori. Predmet istraživanja je provjera mogućnosti primjene iskustava Italije i drugih mediteranskih zemalja kad je u pitanju prečišćavanje otpadnih voda fitodepuracijom. U eksperitalnom dijelu u cilju dokazivanja efikasnosti prečišćavanja otpadnih voda fitodepuracijom, dati su podaci analiza osnovnih parametara otpadnih voda na ulazu i izlazu sistema za prečišćavanje otpadnih voda u Dicomanu (Firenca), nakon čega je razmatrana mogućnost smanjenja troškova primjenom fitodepuracije u odnosu na klasične tehnologije prečišćavanja otpadnih voda, kao i uticaj na životnu sredinu. U radu su korišćene metode analize fizičko-hemijskih parametara, ekonomskig vrednovanja varijanti, kao i procjena uticaja na životnu sredinu. Na kraju, u diskusiji i zaključcima su dati komentari dobijenih rezultata, zaključci i preporuke za dalji istraživački rad u ovoj oblasti, zatim slijedi spisak korišćene literature i aneksi.

Ključne riječi: otpadne vode, prečišćavanje, fitodepuracija, sanitane močvare, održivi razvoj, uticaj na životnu sredinu, biljke.

 

ABSTRACT

This paper examines the possibility of implementation of fitodepuration as one of the methods of purification of waste water in Montenegro. The introductory section provides a brief history of waste water management, with emphasis on the analysis of waste water management in Montenegro, as well as European and domestic legislation in this area. Also in this section are given and the characteristics of waste water and waste water tretment methods are analyzed in strategic documents in Montenegro. The subject of the verification capabilities of application experience of Italy and other Mediterranean countries when it comes to wastewater treatment of fitodepuracija. In eksperital part to demonstrate the efficiency of wastewater treatment fitodepuracija, given the data analysis of the basic parameters of waste water at the entrance and exit system for waste water in Dicomanu (Florence), after which discussed the possibility of reducing costs by applying fitodepuracija compared to conventional treatment technologies waste water, and the impact on the environment. Methods used are analysis of physical chemical parameters, economic evaluation version and estimate the impact on the environment. Finally, in the discussion and conclusions are given reviews of the results, conclusions and recommendations for further research in this area, followed by a list of used literature and annexes.

Key words: wastewater treatment, fitodepuracione, sanitary wetlands, sustainable development, the impact on the environment, plants.

 


 

DRAGAN ĐORĐEVIĆ1, SNEŽANA UROŠEVIĆ2 MILENA MILJKOVIĆ3, MIODRAG STAMENKOVIĆ1

Stručni rad [PDF]
UDC:677.21.027.265.16

Zaštita pamučnih tkanina protiv zapaljivosti

U radu su opisani pojedini postupci zaštite pamučnog tekstila od zapaljenja i gorenja. Uzeta su dva tipa supstrata – 100 % pamučne tkanine sa različitim karakteristikama, varirane su vrste i količine aktivnih agenasa – sredstva za zaštitu od zapaljivosti i gorenja kao i neki uslovi obrade. Cilj istra­živanja je provera efikasnosti primene kombinacije potencijalnih sredstava za zaštitu (polimeri, jedinjenja fosfora, halogena, azota) kao i kontrola ostalih svojstava bitnih za kvalitet tekstilnog proizvoda. Nađeno je da pojedine recepture pružaju odličnu zaštitu tekstilu od gorenja. Vreme gorenja kao i vreme tinjanja su minimalni. Ostali pokazatelji, poput mehaničkih karakteristika ili propustljivost vazduha, pokazuju slabije rezultate dok su svojstva kapilarnosti i dimenzione stabilnosti zadovoljavajuća.

Ključne reči: pamučna tkanina, zapaljivost, sredstva za zaštitu od zapaljivosti i gorenja, vreme gorenja.

 

Protection against the cotton fabrics flammability

Certain procedures for protecting cotton fabrics against ignition and flame spread are described in the paper. There are two types of substrates presented – 100% cotton fabrics with different characteristics, varying type and quantity of active agents – antipyrene and certain processing factors. The objective of the research is to determine the efficiency of using the combination of potential antipyrenes (polymers, phosphorus, halogen, and nitrogen compounds) and to control other characteristics important for the quality of a textile product. Certain combinations resulted in an excellent fabrics protection against ignition. The burning time, as well as the smouldering, is minimal. Other indicators, such as mechanical characteristics or air permeability show less significant results, while the capillary properties and dimensional stability is satisfactory.

Key words: cotton fabric, flammability, antipyrenes, time of burning.

 


B. ĐUKIĆ, S. SMILJANIĆ, A. DOŠIĆ

Stručni rad [PDF]
UDC:621.574.004.54.55

Kontrola depozita u rashladnom sistemu

Rashladni sistemi su veoma važni u funkcionisanju industrijskih i energetskih postrojenja. Osnovni problemi kod otvorenih rashladnih sistema su: korozija, depoziti i biološki rast. U ovom radu obra­đeno je: uzroci i posledice u stvaranju depozita kao i zaštita rashladnog sistema od stvaranja depozita. Eksperimentalno je određivano doziranje inhibitorima-agenasa za sprečavanje depozita bez doziranja korozionog inhibitora i sa doziranjem korozionog inhibitora. Kao inhibitor za sprečavanje depozita korišćen je polimaleat. Rezultati su pokazali da uspešno spreča­vanje stvaranja depozita zavisi od stepena ugušćenja, tj. koncentracije soli u sistemu. Drugi važan faktor je korišćenje korozionog i depozitnog inhibitora. U slučaju korišćenja korozionog inhibitora  na bazi fosfonata utrošak polimaleata smanjuje se do 30% zbog sinergetskog djelovanja fosfonata i polimaleata.

Ključne riječi: depozit, inhibitori, rashladni sistemi.

 

DOPOSIT CONTROL IN COOLING SYSTEM

Cooling systems are very important for the functioning of industry and energy facilities. The most common problems in open cooling systems are: corrosion, deposits and biological growths. In this work we covered the subjects of: causes and effects of deposit creation and the protection of the cooling system against deposit creation. The dosage of inhibitors – deposit preventing agents was determined experimentally, with and without dosing corrosion inhibitors. Polymaleate was used as a deposit inhibitor here. The results showed that the success of deposit inhibition depended on the degree of thickening, i.e. the salt concentration in the system. Another important factor is the use of corrosion and deposit inhibitors. In the case of using corrosion inhibitor based on phosphonates, the consumption of polymaleates is decreased by up to 30% due to the synergetic effect of phosphonates and polymaleates.

Key words: deposit, inhibitors, cooling systems

 


V. NOVAKOVIĆ1, M. GLIGORIĆ2, R. GRUJIĆ1

Stručni rad [PDF]
UDC:628.112.033:622.143

Uticaj upotrebe komprimovanog vazduha pri bušenju, razradi i ispiranju pijezometara i bunara na rezultate ispitivanja fizičko-hemijskog sastava podzemnih voda

Ovim radom se ukazuje na to, da se kiseonik u podzemnim vodama, može zadržati na velikom prostoru i dugo vremena nakon izvođenja i ispiranja pijezometara i bunara, što objektivno može uticati na rezultate ispitivanja fizičko-hemijskog sastava podzemne vode u toku prvog testiranja bunara. U radu su prezentovani podaci o navedenim situacijama u akviferu neogene starosti u Stanarima kod Doboja i u aluvijalnoj izdani u Kozluku kod Zvornika. Kako bi se u budućnosti eliminisao ovaj problem u radu su date preporuke, promjene uobičajene procedure hidrogeoloških istraživanja, da se sagleda efekat aeracije vode u akviferu, tokom razrade bunara.

Ključne reči: bunari, podzemne vode, piezometri, fizičko-hemijski sastav vode

 

INFLUENCE OF USING COMPRESSED AIR FOR DRILLING, DEVELOPMENT AND CLEANING OF THE PIEZOMETERS AND THE WELLS, TO THE RESULTS OF TESTING PHYSICAL-CHEMICAL COMPOSITION OF GROUND WATER

The compressed air is often used for purpose of drilling or quality developing and flushing the piesometers and water wells. This paper suggests, that the oxygen in the groundwater, can keep in a large area, for a long time after the performing and cleaning of the piezometers and water wells, which objectively, might have affect to the the results of physical and chemical composition of groundwater when we test water wells in the first time. The paper presents data about these situations in the Neogene aquifer in the Stanari settlement near of city of Doboj, and in the alluvial aquifer in Kozluk village, near city of Zvornik, by correlation of test results immediately after the performing of water wells and later, during their usage. In order to eliminate this problem, in this paper proposals of future works were made, diferent of the usual procedure of hydrogeological research. It will bi possible to examine the effect of aeration of groundwater in the aquifer, during the performing of the wells.

Key words: groundwater, iron, manganese, ammonia, development of water wells

 


 

MILOŠ PETROVIĆ

Stručni rad [PDF]
UDC:624.012’036.8

Polimerni kompoziti u građevinarstvu

Kompozitni materijali nastaju sjedinjavanjem dva ili više raznolika materijala. Polazni materijali imaju međusobno različite osobine a njihov spoj daje potpuno nov materijal. On ima jedinstvena, sasvim nova i drugačija svojstva u odnosu na sastavne komponente. Cilj je da se poboljšaju strukturne, termičke, hemijske ili neke druge karakteristike pojedinačnih materijala. Komponente se međusobno ne mešaju niti rastvaraju tako da se unutar kompozita jasno razlikuju dve ili više faza. Poboljšane osobine kompozitnih materijala pružaju mogućnost njihove široke primene.

Ključne reči: polimeri, polimerizacija,kopoziti, inhibicija, monomeri…

 

POLYMER COMPOSITES IN CIVIL ENGINEERING

Composite materials formed union of two or more diverse material. The startingmaterials have different properties to each other and their combination with a completely new material he has a unique, completely new and different propertiescompared to the constituent components. The aim is to improve the structural, thermal, chemical or other characteristics of individual materials. The componentsdo not interfere with each other nor to dissolve within the composites clearly distinguish  two or more phases. Improved properties of composite materials offer the possibility of their wide application.

Key words: polymers, polymerization, composites, inhibition, monomers.