Sinthesys of secondary sulfur based concrete and examining its durability in aggressive environment

Gradevinski materijali dolaze u fokus interesovanja u vreme kada otpad, bilo industrijski, bilo komunalni, dobija na znacaju kao potencijalna sirovina. Verovatan razlog za to je osnova gradevinskog materijala- cement, koji u svom sastavu ima i veliki broj uslovno otpadnih materijala koji mogu da vode poreklo od sastojaka ili od energenata koji se koriste za njegovu proizodnju. S jedne strane, primarna primena gradevinskih materijala sve se više širi, ali pored njih i alternativni materijali dobijaju svoje mesto. Modifikacija konvencionalnih gradevinskih materijala uglavnom se vrši korišcenjem nekih od sekundarnih sirovina iz razlicitih industrijskih procesa. Generalno gledajuci, gradevinski materijali i njihovi proizvodi znacajni su akceptori otpadnih materija ukoliko mogu u potpunosti da izvrše njihovu imobilizaciju, pri cemu mora biti ispunjen uslov da ne dolazi do degradacije osnovnih svojstava samog materijala. Danas se najveci broj istraživanja u svetu odnosi na korišcenje pepela iz termoelektrana i ostalih velikih insineratora u cilju dobijanja kvalitetnog gradevinskog materijala široke primene. Prateci slicnu koncepciju, u ovom radu prikazana je i analizirana mogucnost korišcenja sekundarnog sumpora kao alternativnog sastojka betona. Sumpor cesto predstavlja zapostavljen otpad, iako je veliko pitanje da li kolicina proizvedenog sekundarnog sumpora na svetskom nivou premašuje kolicinu pepela kome se pridaje veliki znacaj. Zahvaljujuci tehnološkoj revoluciji, došlo je do vracanja sumpora u atmosferu preradom nafte, prirodnog gasa i II ruda, što predstavlja reverzibilan proces prirodnom uklanjanju sumpora iz atmosfere. Tako se kao nusproizvodi dobijaju sumpor i sumporna kiselina koji danas predstavljaju ozbiljan ekološki problem. Zbog toga je bilo neophodno razmatrati alternativne nacine valorizacije sumpora i sumporne kiseline u realnom procesu (large scale). U tom slucaju, rešenja se mogu naci u korišcenju pomenutih vrsta sekundarnog sumpora u proizvodnji dubriva, imobilizaciji otpadnih materijala prevodenjem u nerastvorna jedinjenja i kao dodatak odgovarajucim gradevinskim materijalima..

Korišćenje obnovljivih izvora – pretvaranje geotermalne energije u električnu

According to the official definition, approved by the European Geothermal Energy Council (EGEC), geothermal energy is energy accumulated as heat below the surface of solid soil. Geothermal energy is thermal energy generated and stored in the Earth. It is generally defined as the part of geothermal heat that can be directly utilized as heat or converted into other types of energy. Geothermal resources vary by location and depth towards the Earth's core. Their use is possible for different purposes depending on their temperature. This paper presents the harnessing geothermal resources for electricity generation. There are three main types of geothermal power plants: dry steam plants, flash steam plants, and binary cycle plants. Dry steam plants pipe hot steam from underground into turbines, which powers the generator to provide electricity. Flash steam plants pump hot water from underground into a cooler flash tank. The formed steam powers the electricity generator. Binary cycle plants pump hot water from underground through a heat exchanger that heats a second liquid to transform it into steam, which powers the generator. In all mentioned systems the used fluids are recycled. It can be concluded that geothermal power plants work similarly to other power plants, but providing the steam for starting the turbine from the earth's interior. The fact that used fluids return to the ground makes geothermal energy resources renewable.Prema zvaničnoj definiciji, koju je odobrilo Evropski savet za geotermalnu energiju (European Geothermal Energy Council- EGEC), geotermalna energija je energija akumulirana kao toplota ispod površine čvrstog tla. Geotermalna energija je toplotna energija koja se generiše i skladišti u Zemlji. Generalno se definiše kao deo geotermalne toplote koji se može direktno koristiti kao toplota ili pretvoriti u druge oblike energije. Geotermalni resursi se razlikuju u zavisnosti od lokacije i dubine u odnosu na jezgro Zemlje. Njihova primena moguća je za različite svrhe u zavisnosti od njihove temperature. Ovaj rad prikazuje upotrebu geotermalnih resursa za proizvodnju električne energije. Postoje tri osnovna principa rada geotermalnih elektrana: suva para (dry steam), separisanje pare (flash steam) i binarni (binary cycle). Postrojenja na suvu paru izbacuju vruću paru iz unutrašnjosti Zemlje u turbine, a ona napaja generator koji daje električnu energiju. Postrojenja sa separisanjem pare pumpaju toplu vodu iz iz unutrašnjosti Zemlje u hladniji rezervoar. Nastala para pokreće generator električne energije. Postrojenja sa binarnim ciklusom pumpaju toplu vodu iz unutrašnjosti Zemlje kroz izmjenjivač toplote čime se greje drugi fluid i pretvara u paru koja pokreće generator. U svim pomenutim sistemima korišćeni fluidi se recikliraju. Može se zaključiti da geotermalne elektrane rade slično kao i druge elektrane, ali paru za pokretanje turbine obezbeđuju iz unutrašnjosti Zemlje. Činjenica da se korišćeni fluidi vraćaju u zemlju čini geotermalne izvore energije obnovljivim

PrečIšćavanje rudničkih otpadnih voda adsorpcijom na letećem pepelu

Bakar je jedan od najzastupljenijih metala u industriji zbog svoje najšire primene u poređenju sa ostalim obojenim metalima. Tokom procesa eksploatacije bakra stvara se velika količina rudničkih otpadnih voda. Zbog toga postoji sve veće interesovanje za rešavanje ekoloških pitanja industrije rudnika bakra. Hemijski sastav rudničkih otpadnih voda je složen i zavisi od hemijskog sastava rude koja se izlužuje tokom eksploatacije. Leteći pepeo je vrsta industrijskog otpada koji može da izazove višestruke ekološke probleme. S druge strane, zbog velike poroznosti i specifične površine, kao i drugih jedinstvenih karakteristika, leteći pepeo se takođe može koristiti kao jeftin i visoko efikasan adsorbens za prečišćavanje rudničkih otpadnih voda. U ovom radu leteći pepeo iz termoelektrane bez prethodnog tretmana i peletiziran korišćen je za sorpciju bakra iz otpadne vode. Rezultati su pokazali da je leteći pepeo efikasan sorbent bakra pri čemu su pelete imale tri puta veći adsorpcioni kapacitet u odnosu na mikronizirani pepeo

Software solution for the mine subsidence prediction based on the stochastic method integrated with the gis

Mining induced the ground subsidence and consequently, damages on objects above excavation works is a serious problem all over the world. In this paper, a new approach for subsidence and deformation prediction based on the stochastic Pataric-Stojanovic method is presented. Since the calculation using the equations of this method is very complex, the original computer program package with the title MITSOUKO has been purposely designed. The MITSOUKO program enables calculating at any point of the land surface and representing the results owing to the possibility of their integration and further processing in the Geographical Information System (GIS). The components of the GIS are used to realize the spatial analysis

Tehnike neuromarketinga - savremeni način istraživanja ponašanja potrošača

Neuromarketing studies reveal significant new information about human preferences by measuring brain activity. The use of neuromarketing enables marketers to discover the desires and needs of consumers and therefore define their goals. This method can reveal unconscious thoughts, feelings and desires of consumers to manage their everyday purchasing decisions. The field of neuromarketing uses advances in technology and goes beyond the traditional methods of qualitative and quantitative research. Focusing on the brain's response to consumer marketing stimuli, it helps us clarify what consumers think in a situation where they are faced with a product. With the increasing application of new technologies, a large number of companies are involved in the implementation of neuromarketing studies in order to improve their sales. With this in mind, this paper will discuss neuromarketing techniques, when they are applied, which tools they are measured with, as well as the advantages and limitations when applying them.Neuromarketinška istraživanja otkrivaju značajne nove informacije o ljudskim željama merenjem moždane aktivnosti. Upotreba tehnika neuromarketinga omogućava marketinškim stručnjacima da otkriju potrebe potrošača i da prema tim saznanjima usmeravaju svoje ciljeve. Ovim metodama mogu se otkriti nesvesne misli, osećanja i žudnje potrošača, koje upravljaju njihovim svakodnevnim odlukama o kupovini. Polje neuromarketinga koristi napredak u tehnologiji i prevazilazi tradicionalne (konvencionalne) metode kvalitativnog i kvantitativnog istraživanja. Fokusirajući se na reakcije mozga potrošača, pomaže da se razjasne šta potrošači misle u situaciji kada su suočeni sa potencijalnom kupovinom nekog proizvoda. Sa povećanjem primene novih tehnologija, veliki broj kompanija uključio se u sprovođenje neuromarketinških studija, kako bi, pre svega, poboljšali prodaju svojih proizvoda i povećali profit. Zbog toga se u ovom radu prikazuju tehnike neuromarketinga, uslovi u kojima se koriste, alati koji se upotrebljavaju, kao i prednosti i ograničenja njihove primene

Possibilities of waste sulfur valorization in eco-friendly products

Modifikacija konvencionalnih građevinskih materijala obično se izvodi upotrebom različitih otpadnih materijala. U ovom istraživanju biće prikazana upotreba sekundarnog sumpora kao veziva u betonu. Sumporni beton je termoplastični kompozit koji se sastoji od mineralnog agregata i punila, sa sumporom kao vezivom na temperaturi višoj od tačke očvršćavanja sumpora. Ovaj relativno nov građevinski materijal može da zameni konvencionalni Portland cementni beton u raznim konstrukcijama. U ovom radu biće prikazana svojstva sumpornog betona, kao i rezultati ispitivanja njegove postojanosti u agresivnim sredinama. U cilju ispitivanja svojstava, primenjene su destruktivne i nedestruktivne metode, dok su svojstva korelisana sa strukturom materijala.Predavanje po pozivu (plenarno) - Dr Sanja Martinović / Invited lecture (plenary) - Dr. Sanja Martinovi

X-ray structural analysis of the BaO and TiO2 starting compounds and initial mechanochemical activation

The aim of this research was to obtain an initial characterization of the BaO and TiO2components, as well as to conduct preliminary research into the possibility of activating the initial components in order toobtain barium titanate. Chemical and X-ray structural analysis of the initial components was performed. In order to determine the possibility of applying a mechanochemical activator and the activation time in which the first intermediate compounds were formed by the activation of the starting substances, the system was activated for 30 minutes. After this, an X-ray structural analysis was performed and certain changes in the crystal lattice of the starting components were made. X-ray structural analysis showed that during grinding, amorphization of the initial components occurred, which is the first stage in the process of obtaining titanate, as well as the presence of a small amount of barium titanate, which is indicating the presence of an intermediate compound in the process of finally obtaining barium titanate

Blast furnace refractories: Past, present, future

Most of the refractories used today are related to iron and steel industry. Grate part of the refractory lining related to blast furnace are combination of different refractory materials selected for different parts of furnace, as well as different process conditions and temperature range. Selection of appropriate refractory combination depends on knowledge and demands for iron making system in combination with the physical, mechanical and chemical properties of the proposed refractories. An improper understanding of the above factors often leads to a refractory failure which, subsequently, becomes a complex problem to solve. Refractory linings whether it is of a blast furnace or any other furnace, usually fail due to any number or combination of such factors. For the convenience of understanding, here we will discuss the types of refractory lining required in a blast furnace area as well as the trend in the refractory lining pattern that has been used during the last decades

Non-destructive evaluation of sulfur-polymer composite behavior under induced destruction influence

In order to avoid undesirable effects, caused by interactions between the material and environment, changes in properties of materials during their exploitation periods have to be determined. In this research, the induced destruction methodology was applied for evaluation of material behavior. The methodology is based on the usage of agents in increased concentrations that can lead to destruction of the material (cause changes in physical, chemical and mechanical properties) as fast as possible. Sulfur-polymer composite was exposed to the influence of hydrochloric acid, which was chosen as an induced destruction agent. The analysis of sulfur-polymer composite behavior required methods capable of quantifying the material microstructural characteristics. Since sulfur-polymer composite is inhomogeneous material, evaluation of its properties, as well as the effect of external influence on its microstructure, was investigated using non-destructive methodologies. Image analysis and ultrasonic measurements were applied to quantify the material destruction on the surface and in the bulk. Morphological and structural changes in the inner structure of sulfur-polymer composite were inspected by scanning electron microscopy (SEM). According to the obtained results, used methodologies present a powerful tool for the characterization of phenomena occurring in the specimens during the investigation

Leaching behavior of sulfur concrete with fly ash used for removal of heavy metals from wastewater

When considering the materials that have become waste in a technological process, one way of their immobilization is for the production of certain new materials. The basic fact is to provide the environmentally acceptable level of the produced material. In this research fly ash from ’’Power Plant Nikola Tesla’’ Obrenovac was used as an sorbent for removal of heavy metals from flotation wastewater originating from artificial lake ’’Cerovo’’. After the sorption, fly ash was used as filler for the production of sulfur concrete. Sulfur concrete samples with standard dimensions were subjected to leaching tests by immersion in distilled water during the period of up to six months. Leaching is the process by which different contaminants are released from the solid phase into the water phase. The process itself is universal, as any material exposed to contact with water will leach components from its surface or its interior depending on the porosity of the material considered. Results of examining leaching degree of heavy metals from the sulfur concrete samples with fly ash as filler showed that the leaching degree of all metals (copper, cadmium, zinc, iron, nickel) except manganese was negligible. It can be concluded that in the sulfur concrete samples with fly ash as filler, immobilization of heavy metals occurred