Influence of bentonite and zeolite on Cs+ and Co2+ cement matrix leaching phenomena

The probability of Cs+ and Co2+ ions retention by immobilization processes in the cement matrix was determinate as the subject of analyses: matrix design, water/cement ratio, and structure porosity. Comparison of experimental results was accomplished by Hespe standard leaching method. Diffusion and semi-empirical models were used for the assessment of the washing rate as a function of time. The higher value of cement matrix mechanical resistance corresponds to a lower value of Co2+ and Cs+ ions leaching. The Co2+ leaching level was more than two orders of magnitude less than the leaching level of Cs+. The influence of bentonite and zeolite on Co2+ leaching reduction was significantly smaller in comparison with Cs+, while zeolite had a higher Cs+ and Co2+ sorption ability than bentonite. Under static leaching conditions, the contribution of diffusion to the total transport of ions in the matrix porous medium was dominant. The contribution of matrix dissolution was insignificant concerning the dominant contribution of diffusion and surface washing. The semi-empirical model showed a better approximation of the Co2+ and Cs+ ions laboratory leaching process

Pollutants Characterization Role in Phytoremediation of Coal Tailings Dams and Ash Ponds

Uloga karakterizacije i kvantifikacije polutanata devastiranih zemljišta od izuzetne je važnosti pri procesu njihove fitoremedijacije. Kontaminirana zemljišta se po svojim karakteristikama razlikuju od plodnog zemljišta po sastavu i koncentraciji toksičnih materija, količini vlage, nutrienata, hu- minskih supstanci i ostalim pedološkim karakteristikama. Fizičko-hemijskim, biološkim i tehnolo- škim analizama moguće je definisati nivo kontaminacije i mere koje su neophodne da bi se izvršila remedijacija ovakvih zemljišta radi preventivencije daljeg zagađivanja i pripreme zemljišta za ko- načnu prenamenu. Ovaj rad se bavi karakterizacijom jalovišta ugljenokopa i pepelišta termoe- lektrana nastalim eksploatacijom uglja u svrhu dobijanja električne energije. Pravilnim monito- ringom i izborom remedijacionih biljaka ovi deposoli mogu da posluže za gajenje ekoremedija- cionih zasada, posebno drvenastih kultura, koje dalje mogu da se koriste u građevinarstvu, drvnoj industriji ili kao biomasa za dobijanje energije. Izbor biljnih kultura zavisi od vrste kontaminacije, sposobnosti biljaka da detoksifikuju ove devastirane deposole uz dodatne agro-mere, kao i mogućnosti da njihovi korisni delovi ostanu nekontaminirani kako bi kasnije poslužili kao sirovina. Na osnovu nivoa i vrste kontaminacije biraju se pogodne biljne kulture, vrši biomonitoring procesa i određuje efekat revitalizacije zemljišta. U tekstu je najviše pažnje posvećeno hemijskom sastavu, pravilnom uzorkovanju, pripremi uzoraka i fizičko-hemijskim analizama deposola i biljnog materi- jala, koji zajedno predstavljaju čvrste uzorke.Characterization and quantification pollutants role of devastated soils has significant importance in their phytoremediation process. Characteristics of contaminated soils are different from fertile soils by composition and concentration of toxic substances, amount of moisture, nutrients, humic substances and other pedological characteristics. By physico-chemical, biological and technolo- gical analyses, it is possible to define contamination level and necessary measures for complete soil remediation for further pollution prevention and preparation for final adaptation. This paper deals with characterization of coal tailings dams and thermoelectric power plant ash ponds occurred by electricity production process. With proper monitoring and remediation plants selection these deposols could be used for growing ecoremediation biomass, especially woody cultures, which could be used in construction and wood industry or as energetic biomass. Choice of plants depends on contamination type, ability of plants to detoxify devastated deposols with additional agro- measures, as well as possibility of their useful parts to remain uncontaminated for later usage as raw material. Selection of suitable plants, biomonitoring and determination of soil revitalization effect are based on contamination level and type. This text is focused on chemical composition, proper sampling, sample preparation and physico-chemical analyses of deposols and plant material, which both are the solid samples

Galactic interstellar filaments as probed by LOFAR and Planck

Recent Low Frequency Array (LOFAR) observations at 115-175 MHz of a field at medium Galactic latitudes (centered at the bright quasar 3C196) have shown striking filamentary structures in polarization that extend over more than 4 degrees across the sky. In addition, the Planck satellite has released full sky maps of the dust emission in polarization at 353GHz. The LOFAR data resolve Faraday structures along the line of sight, whereas the Planck dust polarization maps probe the orientation of the sky projected magnetic field component. Hence, no apparent correlation between the two is expected. Here we report a surprising, yet clear, correlation between the filamentary structures, detected with LOFAR, and the magnetic field orientation, probed by the Planck satellite. This finding points to a common, yet unclear, physical origin of the two measurements in this specific area in the sky. A number of follow-up multi- frequency studies are proposed to shed light on this unexpected finding.Comment: 6 pages, 4 figures, accepted for publication in MNRAS Letter

Methodology of Cost-Benefit Analysis of Impact Assessment on the Environment

Standardna analiza troškova i koristi podrazumeva kvantitativno vrednovanje opravdanosti i isplativosti projekta. Odluka o izvođenju projekta donosi se na osnovu analize, čija izrada je diskreciono pravo ulagača. Investicioni projekat nužno utiče na životnu sredinu u kojem se ostvaruje. Cost-benefit analiza pokazuje da li projekat ima uravnotežen pristup zaštiti životne sredine u skladu sa održivim razvojem, iz pozicije poslovnog interesa. Održivi razvoj dopušta proizvodna ulaganja koja ostvaruju profit, ali iz kog se mora izdvajati i doprinos za životnu sredinu. Ovakav pristup nema alternativu. Zakonom je propisana obaveza ulagača da analizom troškova i koristi dokaže da planirani projekt neće štetiti životnoj sredini.Standard cost-benefit analysis involves quantitative feasibility evaluation and project cost-effectiveness. Investment decision should be analysis based, it is investors discretion. Investment project necessarily has environment impact where it is realized. Cost-benefit analysis shows that project have a balanced approach to environmental protection in respect with sustainable development, from the business interests position. Sustainable development allows investments with profits, but requires a contribution to the environment. This approach has no alternative. Investors legislative obligations is cost-benefit analysis which proves that planned project will not harm the environmen

Properties of pedestrians walking in line: Stepping behavior

In human crowds, interactions among individuals give rise to a variety of self-organized collective motions that help the group to effectively solve the problem of coordination. However, it is still not known exactly how humans adjust their behavior locally, nor what are the direct consequences on the emergent organization. One of the underlying mechanisms of adjusting individual motions is the stepping dynamics. In this paper, we present first quantitative analysis on the stepping behavior in a one-dimensional pedestrian flow studied under controlled laboratory conditions. We find that the step length is proportional to the velocity of the pedestrian, and is directly related to the space available in front of him, while the variations of the step duration are much smaller. This is in contrast with locomotion studies performed on isolated pedestrians and shows that the local density has a direct influence on the stepping characteristics. Furthermore, we study the phenomena of synchronization -walking in lockstep- and show its dependence on flow densities. We show that the synchronization of steps is particularly important at high densities, which has direct impact on the studies of optimizing pedestrians flow in congested situations. However, small synchronization and antisynchronization effects are found also at very low densities, for which no steric constraints exist between successive pedestrians, showing the natural tendency to synchronize according to perceived visual signals.Comment: 8 pages, 5 figure

Foregrounds for observations of the cosmological 21 cm line: II. Westerbork observations of the fields around 3C196 and the North Celestial Pole

In the coming years a new insight into galaxy formation and the thermal history of the Universe is expected to come from the detection of the highly redshifted cosmological 21 cm line. The cosmological 21 cm line signal is buried under Galactic and extragalactic foregrounds which are likely to be a few orders of magnitude brighter. Strategies and techniques for effective subtraction of these foreground sources require a detailed knowledge of their structure in both intensity and polarization on the relevant angular scales of 1-30 arcmin. We present results from observations conducted with the Westerbork telescope in the 140-160 MHz range with 2 arcmin resolution in two fields located at intermediate Galactic latitude, centred around the bright quasar 3C196 and the North Celestial Pole. They were observed with the purpose of characterizing the foreground properties in sky areas where actual observations of the cosmological 21 cm line could be carried out. The polarization data were analysed through the rotation measure synthesis technique. We have computed total intensity and polarization angular power spectra. Total intensity maps were carefully calibrated, reaching a high dynamic range, 150000:1 in the case of the 3C196 field. [abridged]Comment: 20 pages, 22 figures, accepted for publication in A&A. A version with full resolution figures is available at http://www.astro.rug.nl/~bernardi/NCP_3C196/bernardi.pd

Mycoremediation as Innovation Model of Ecoremediation of Highly Contaminated Soils

Mikoremedijacija je oblik bioremedijacije koji pomoću gljiva vrši detoksikaciju zagađenih zemljišta i voda. Gljive igraju važnu ulogu u svim ekosistemima i u stanju su da regulišu protok hranljivih materija i energije. Jedna od osnovnih uloga gljiva u ekosistemu je razgradnja koju vrše micelijumi. Micelijumi izlučuju vanćelijske enzime i kiseline koje razgrađuju lignin i celulozu. To su organska jedinjena iz lanca ugljenika i vodonika strukturom slična mnogim organskim zagađivačima. Na taj način razgrađuju lance toksina u jednostavnije i manje toksične hemikalije. Enzimi gljive mogu razložiti neke od najotpornijih materijala napravljenih od strane čoveka i prirode kao što su nafta, ulje, pesticidi, lijekovi, tekstilne boje itd. Neke od poznatih gljiva koje se koriste u mikoremedijaciji su: bukovača (Pleurotus ostreatus), ćuranov rep (Trametes versicolor), Shiitake gljive (Lentinus edodes), gljive bele truleži (Phanerochaete chrysosporium), Reishi gljive (Ganoderma lucidum), smrčak (Morchella Conica) itd. Najčešći metod mikoremedijacije je da se inokulišu drveni opiljci ili slama sa micelijumom gljive i stave na površinu kontaminiranog zemljišta ili tamo gde kontaminirana voda mora da proteče kroz to. U zavisnosti od nivoa zagađenja neophodno je izvršiti nekoliko uzastopnih primena da bi se toksini smanjili na prihvatljiv nivo. Micelije luče enzime koji usvajaju toksične materije sve dok se ne razviju u odrasle pečurke. Stoga je bitno zadržati miceliju da što duže raste prije nego se pretvori u oblik ploda. Prolećna inokulacija je bolja nego jesenja, jer micelije imaju više vremena da se rašire. Mnogi faktori utiču na brzinu i sposobnost apsorpcije i razgradnje toksina pomoću gljiva, a neki od njih su priroda ugljovodonika, temperatura, pH vrednost zemljišta, kiseonik, vlažnost vazduha i dr.Mycoremediation is the form of bioremediation which helps with fungi performing detoxification of contaminated soils and waters. Fungi play important role in all environments and are able to regulate the transfer of nutritious materials and energy. One of the basic roles of fungi in ecosystem is degradation which is performed by mycelia. Mycelia excrete extracellular enzymes and acids which break lignin and cellulose. Those are organic compounds from the chain of carbon and hydrogen similar by its structures to many organic pollutants. This way they break down toxins into simpler and less toxic chemicals. Fungi enzymes can break down some of the most resistant materials made by man and nature like crude oil, oil, pesticides, medicine, textile colors, etc. Some of know fungi which are used in mycoremediation are: Oysters (Pleurotus ostreatus), Turkey Tail (Trametes versicolor), Shittake mushrooms (Lentinus edodes), White-rot fungi (Phanerochaete chrysosporium), Reishi mushrooms (Ganoderma lucidum), Morel (Morchella Conica), etc. The most common method is to inoculate wood chips or straw with your mycoremediators and put that substrate on top of the problem soil or where the contaminated water has to flow through it. Depending on the level of contamination it is necessary to execute several consecutive applications in order for toxins to be reduced to acceptable level. Mycelia secrete enzymes which absorb toxic material all the time until they develop to grown mushrooms. Therefore, it is important to keep mycelia to grow as long as possible before it transforms in a form of fruit. Spring inoculations work better than fall inoculations as the mycelium has more time to grow- out. Many factors affect the speed and capability of absorption and degradation of toxins using fungi, and some of them are the nature of hydrocarbons, temperature, PH value of the soil, oxygen, humidity of air and similar

Simple and Low-cost Fiber-optic Sensors for Detection of UV Radiation

In this paper two simple and low-cost fiberoptic sensors for detection of UV radiation are presented. A U-shaped sensor covered with an UV marker for UV radiation detection and a fiber-optic sensor with one end covered with powder from a mercury lamp are produced and described in details. Both sensors are made of large-core PMMA plastic optical fibers. As UV sources, a solar simulator and four different UV lamps are used. The light spectrum on the fiber output is measured by using an USB spectrometer. Dependence of output light intensity on the distance of end-type sensor with powder from a mercury lamp from UV lamp is investigated as well. On the output of the sensor covered with powder from a mercury lamp are obtained peaks of fluorescent emission at approximately 616 nm and 620 nm wavelengths

Upotreba solidifikovanih frakcija industrijskog opasnog otpada u niskogradnji: Studija slučaja u Republici Srbiji

Utilization possibilities of solidified fractions of industrial hazardous waste obtained by mixing with inert materials in construction were investigated. Waste mineral oils, water-hydrocarbon emulsions mixture, and waste filter cakes from the physico-chemical treatment of wastewater generated by washing of patterned rollers for a printing machine, were used as models of industrial hazardous waste in the solidification process. Investigation comprised preparation of concrete and asphalt mixtures for further testing. The solidified powder was analyzed regarding the granulometric composition, while the obtained concrete samples were further subjected to compressive strength determination, whereas the asphalt mixtures were tested in the context of potential waterproofing materials. According to the obtained leaching test results, all the samples met the required conditions for further application. Compressive strength test results were in the range of 8.7 – 22.6 MPa. Still, the measured compressive strength values were lower than expected, which is explained using solidified powder fractions of smaller grain size. According to the results, it can be concluded that the investigated mixtures cannot be used for structural building elements, but their usage is recommended for elements such as pavements, roadside, path cubes, concrete haberdashery, etc. Asphalt mixtures showed acceptable properties in terms of mechanical, durability, and waterproofing tests.Ispitivane su mogućnosti korišćenja solidifikovanih frakcija industrijskog opasnog otpada dobijenog njegovim mešanjem sa inertnim materijalima u građevinarstvu. Kao predstavnici industrijskog opasnog otpada u procesu solidifikacije korišćena su otpadna mineralna ulja, mešavina vodeno-ugljovodonične emulzije i otpadne filter pogačeiz fizičko-hemijskog tretmana otpadnih voda nastalih pranjem dezen valjaka na mašini za štampanje. Istraživanje je podrazumevalo pripremu betona i asfaltne mešavine za dalja ispitivanja. Utvrđen je granulometrijski sastav solidifikovanog praha, uzorci betona su dalje podvrgnuti određivanju čvrstoće na pritisak, a asfaltne mešavine su ispitivane u kontekstu hidroizolacionih materijala. Prema dobijenim rezultatima ispitivanja luženja, svi uzorci su ispunjavali potrebne uslove za dalju primenu. Rezultati ispitivanja čvrstoće na pritisak bili su u opsegu od 8,7 – 22,6 MPa. Izmerene vrednosti čvrstoće na pritisak bile su niže od očekivanih, što se objašnjava upotrebom solidifikovanih frakcija manje granulacije. Na osnovu dobijenih rezultata može se zaključiti da se ispitivane mešavine ne mogu koristiti za konstruktivne građevinske elemente, te se preporučuje njihova upotreba za građevinske elemente kao što su trotoari, ivičnjaci, kocke za staze, betonska galanterija i dr. Asfaltne mešavine su pokazale prihvatljiva svojstva u pogledu mehaničkih, ispitivanja izdržljivosti i hidroizolacije

Poređenje japanskih i srpskih bentonita u kompoziciji cement-jonoizmenjivačka smola-bentonitna glina

To assess the safety of disposal of radioactive waste material in cement, curing conditions and time of leaching radionuclides 137Cs have been studied. Leaching tests in cement-ion exchange resins-bentonite matrix, were carried out in accordance with a method recommended by IAEA. Curing conditions and curing time prior to commencing the leaching test are critically important in leach studies since the extent of hydration of the cement materials determines how much hydration product develops and whether it is available to block the pore network, thereby reducing leaching. Incremental leaching rates Rn(cm/d) of 137 Cs from cement-ion exchange resins-bentonite matrix after 60 days were measured. In this paper we compared two bentonite clay as sorption componente, from Japan and Serbia. The results presented in this paper are examples of results obtained in a 30-year concrete testing project which will influence the design of the engineer trenches system for future central Serbian radioactive waste disposal center.Da bi se procenila bezbednost odlaganje radioaktivnog otpadnog materijala u cementu, prouĉavan je stepen izluţivanja radionuklida 137Cs. Testovi izluţivanja radjeni su za kompoziciju cementa-jonoizmenjivaĉke smole i bentonita i sprovedene su u skladu sa postupkom preporuĉenog od IAEA. Vreme sušenja pre otpoĉinjanja liĉing testa je od suštinske vaţnosti u studijama izluţivanja, jer uticaj hidratacije cementa odreĊuje koliko se hidratacija proizvoda razvija i da li je od uticaja na blokadu pora, ĉime se smanjuje curenje radionuklida iz matriksa . U ovom radu poredjena su dva bentonita kao sorpcione komponente , iz Japana i Srbije . Rezultati prikazani u ovom radu su primeri rezultata 30-godišnjeg projekta sistema inţenjerskih rovova za buduće srpsko centralno odlagalište radioaktivnog otpada.XXVIII Симпозијум Друштва за заштиту од зрачења Србије и Црне Горе, 30. септембар - 02. октобар 2015.Proceedings: [https://vinar.vin.bg.ac.rs/handle/123456789/9668