Exploring and Monitoring of Methane Hydrate Deposits

Relatively recently, in the last 20 years, it was discovered that methane hydrate (MH) deposits are globally distributed in the permafrost and oceans. Before 1965 when first deposits were discovered in nature, it was believed that MH can occur only in laboratory conditions or in vast parts of the Universe. Presently it is presumed that this solid crystalline compounds in which CH4 molecules occupies the water ice lattices (nominal chemical formula of MH is C4H62O23) can serve as an energy source favorably to the all of the world remaining conventional hydrocarbon sources. The worldwide estimates of MH deposits range from 2x1014 m3 to 3.053x1018 cubic meters. This uncertainty partly results from our limitations in geological understanding of the MH deposits, which is due to the relatively bad quality of data obtained by presently available seismic and electromagnetic techniques. Moreover, MH deposits can become vulnerable to climate changes, which were already occurring in geological past whit tremendous consequences for the global life on Earth. Thus, further development of advanced techniques is needed to enhance our abilities to better characterize, quantify and monitor the MH deposits. In the work presented 14 MeV neutrons and associated alpha particle imaging (API) where used to quantify the amount of MH in the sample. Samples were prepared from sea sediment, quartz sand and MH simulant. MH simulant with chemical formula C4H46O23 was made from sucrose (25 % by mass) and water. MH quantity was measured by measuring the carbon content in the sample [1-8]

Exploring and Monitoring of Methane Hydrate Deposits

Relatively recently, in the last 20 years, it was discovered that methane hydrate (MH) deposits are globally distributed in the permafrost and oceans. Before 1965 when first deposits were discovered in nature, it was believed that MH can occur only in laboratory conditions or in vast parts of the Universe. Presently it is presumed that this solid crystalline compounds in which CH4 molecules occupies the water ice lattices (nominal chemical formula of MH is C4H62O23) can serve as an energy source favorably to the all of the world remaining conventional hydrocarbon sources. The worldwide estimates of MH deposits range from 2x1014 m3 to 3.053x1018 cubic meters. This uncertainty partly results from our limitations in geological understanding of the MH deposits, which is due to the relatively bad quality of data obtained by presently available seismic and electromagnetic techniques. Moreover, MH deposits can become vulnerable to climate changes, which were already occurring in geological past whit tremendous consequences for the global life on Earth. Thus, further development of advanced techniques is needed to enhance our abilities to better characterize, quantify and monitor the MH deposits. In the work presented 14 MeV neutrons and associated alpha particle imaging (API) where used to quantify the amount of MH in the sample. Samples were prepared from sea sediment, quartz sand and MH simulant. MH simulant with chemical formula C4H46O23 was made from sucrose (25 % by mass) and water. MH quantity was measured by measuring the carbon content in the sample [1-8]

Evaluation of elemental composition of sediments from the Adriatic Sea by using EDXRF technique.

723 sediment samples collected along the eastern Adriatic coast have been analyzed using Energy Dispersive X-Ray Fluorescence. Factor Analysis and GIS have been used for the evaluation of the resulting data base containing information on K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Ga, As, Br, Rb, Sr, Y, and Pb concentration levels in order to find spatial relationships in distribution of measured elements. This study can be used to identify background values and to evaluate sediment quality standards

Evaluation of elemental composition of sediments from the Adriatic Sea by using EDXRF technique.

723 sediment samples collected along the eastern Adriatic coast have been analyzed using Energy Dispersive X-Ray Fluorescence. Factor Analysis and GIS have been used for the evaluation of the resulting data base containing information on K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Ga, As, Br, Rb, Sr, Y, and Pb concentration levels in order to find spatial relationships in distribution of measured elements. This study can be used to identify background values and to evaluate sediment quality standards

Detection of hidden explosives in different scenarios with the use of nuclear probes

Abstract The detection of landmines by using available technologies is a time consuming, expensive and extremely dangerous job, so that there is a need for a technological breakthrough in this field. Atomic and nuclear physics based sensors might offer new possibilities in de-mining. Technology and methods derived from the studies applied to the detection of landmines can be successfully applied to the screening of cargo in customs inspections

Exploring and Monitoring of Methane Hydrate Deposits

Relatively recently, in the last 20 years, it was discovered that methane hydrate (MH) deposits are globally distributed in the permafrost and oceans. Before 1965 when first deposits were discovered in nature, it was believed that MH can occur only in laboratory conditions or in vast parts of the Universe. Presently it is presumed that this solid crystalline compounds in which CH4 molecules occupies the water ice lattices (nominal chemical formula of MH is C4H62O23) can serve as an energy source favorably to the all of the world remaining conventional hydrocarbon sources. The worldwide estimates of MH deposits range from 2x1014 m3 to 3.053x1018 cubic meters. This uncertainty partly results from our limitations in geological understanding of the MH deposits, which is due to the relatively bad quality of data obtained by presently available seismic and electromagnetic techniques. Moreover, MH deposits can become vulnerable to climate changes, which were already occurring in geological past whit tremendous consequences for the global life on Earth. Thus, further development of advanced techniques is needed to enhance our abilities to better characterize, quantify and monitor the MH deposits. In the work presented 14 MeV neutrons and associated alpha particle imaging (API) where used to quantify the amount of MH in the sample. Samples were prepared from sea sediment, quartz sand and MH simulant. MH simulant with chemical formula C4H46O23 was made from sucrose (25 % by mass) and water. MH quantity was measured by measuring the carbon content in the sample [1-8]

Obrada otpadnih voda od pranja brodova kombinacijom fizičko-kemijskih metoda

The aim of this study was to investigate the effi ciency of (1) chemical precipitation by calcium oxide, (2) coagulation/flocculation by ferric chloride (FC), and (3) the combination these two methods in reducing the toxicity of wastewater generated by boat pressure washing. All three methods gave satisfactory results in the removal of colour, turbidity, Cr, Fe, Cu, Zn, and Pb. The concentrations of heavy metals were lowered below national limits with 1 g of CaO, 2.54 mg of Fe3+ in the form of FeCl3×6H2O, and the combination of 0.25 g of CaO and 5.08 mg of Fe3+ per 50 mL of wastewater. Both CaO (1.50 g per 50 mL of wastewater) and FC proved efficient, but their combination yielded a significantly better performance: 99.41 %, 100.00 %, 97.87 %, 99.09 %, 99.90 %, 99.46 % and 98.33 % for colour, turbidity, Cr, Fe, Cu, Zn, and Pb respectively. For colour, Cr, Cu, Zn, and Pb removal efficiencies increased in the following order: FC<CaO<CaO+FC, while this order for turbidity and Fe was as follows: CaO<FC<CaO+FC. As expected, all three methods increased the concentration of total dissolved solids in the final effluent. Our results suggest that the combined treatment of marina wastewaters with calcium oxide followed by ferric chloride is efficient, cost-effective, and user-friendly.Radi smanjenja toksičnosti otpadnih voda koje nastaju pranjem brodova premazanih bojama protiv obraštaja primijenjene su tri metode obrade: (1) kemijsko taloženje s pomoću kalcijeva oksida, koagulacija/flokulacija s pomoću željezova klorida (FC) i (3) kombinacija ovih dviju metoda. Sve tri metode dale su zadovoljavajuće rezultate u uklanjanju boje, mutnoće, kroma, željeza, bakra, cinka i olova. Koncentracije teških metala niže od graničnih vrijednosti postignute su nakon tretmana s 1 g CaO ili 2,54 mg Fe3+ dodanog u obliku FeCl3×6H2O ili kombinacijom od 0,25 g CaO i 5,08 mg Fe3+ na 50 mL otpadne vode. Optimalne vrijednosti uklanjanja boje, mutnoće, Cr, Fe, Cu, Zn odnosno Pb s pomoću CaO (1,50 g na 50 mL) bile su 99,07 %, 99,54 %, 86,97 %, 96,77 %, 97,81 %, 98,76 % odnosno 84,10 %, dok su u slučaju željezova klorida te vrijednosti iznosile 98,76 %, 99,85 %, 78,99 %, 97,35 %, 96,77 %, 98,53 % odnosno 78,99 %. Značajno viši stupanj uklanjanja postignut je kombinacijom navedenih dvaju pristupa čime je postignuta maksimalna učinkovitost uklanjanja i to 99,41 % boje, 100,00 % mutnoće, 97,87 % kroma, 99,09 % željeza, 99,90 % bakra, 99,46 % cinka i 98,33 % olova. Za boju, krom, bakar, cink i olovo učinkovitost uklanjanja raste ovim redoslijedom: FC <CaO <CaO + FC dok za mutnoću i željezo raste u ovom nizu: CaO <FC <CaO + FC. Sukladno očekivanju, sve tri metode povećavaju koncentraciju ukupne otopljene tvari u konačnom ispustu. Naši rezultati pokazuju da je primijenjeni način pročišćavanja otpadnih voda iz marina kombinacijom kalcijeva oksida i željezova klorida učinkovit s obzirom na stupanj uklanjanja, s povoljnim odnosom stupnja pročišćavanja i cijene te jednostavan za primjenu