Pilot Experiment Of Immobilization Of Contaminants In-Situ

At the end of 2006 the project of pilot experiment of immobilization of contaminants in-situ was prepared in DIAMO, s. p., o. z. TUU. Realisation of the experiment is planned for years 2007 and 2008. The principle of immobilization of contaminants in-situ is to develop special conditions in water bearing sandstone sediments when transformation of contaminants from mobile form to immobile form can happen. Under the conditions of remediation after chemical mining (using sulphuric acid) of uranium on the deposit Straz it means injecting suitable alkaline medium and its spreading in contaminated sandstone aquifer. It will lead to decreasing of acidity of contaminated groundwater and precipitating of contaminants (SO42-, Al, Fe) in pores. This process is followed by co-precipitation and sorption of other toxic contaminants as As and Be. The results of the pilot experiment will be used for design of application of method of immobilization in-situ in the frame of remediation after chemical mining of uranium on the deposit Straz with the aim to decrease time and costs of the whole remediation process

2-(2-Hydroxy­ethyl)-3-[(2-hydroxy­ethyl)imino]isoindolin-1-one

In the crystal structure of the title compound, C12H14N2O3, mol­ecules are packed into layers parallel to (100). Each layer contains centrosymmetric dimers formed by a pair of strong O—H⋯N hydrogen bonds with an R 2 2(10) motif, while strong O—H⋯O hydrogen bonds forming C(10) chains connect mol­ecules into a two-dimensional network. Additional stabilization is supplied by weak C—H⋯O hydrogen bonds and weak π–π stacking inter­actions with centroid–centroid distances in the range 3.4220 (7)–3.9616 (7) Å

Characteristics of anomalous drip in Punkva caves (Moravian Karst)

Cave speleothems grow from supersaturated dripwaters and store information about various karst processes along the water flow path. Anomalous non-saturated waters may occur if (1) rainfall water passes very rapidly through karst profile or if (2) two saturated waters of different compositions are mixed. The low mineralization close to saturation could be reached also as (3) result of calcite precipitating prior the water enters the cave. The hydrogeochemistry of four dripwaters in the Punkva Caves (Moravian Karst) was systematically studied for anomalous properties during one-year period. The drips are situated in a passage behind Přední Dóm Chamber (CP1 and CP2, 24 samples each), in Tunnel Corridor (TC1, 24 samples), and in Zadní Dóm Chamber (ZD1, 6 samples). The dripwaters CP1, CP2, and ZD1 show various flow regimes but very similar hydrogeochemical properties: electric conductivity (EC = 550–630 μS/cm), saturation (SIcalcite = 0.8–1.2), and Mg/Ca ratio (1000*(Mg/Ca) = 15–20). In contrast, the dripwater TC1 shows stable drip rate and EC = 275–350 μS/cm, SI = -0.1 to 0.3, and almost thrice as high Mg/Ca ratios as other drips. High and stable discharge of the drip TC1, combined with low EC, SI close to zero, and high Mg/Ca ratio indicate that a prior precipitation of calcite is responsible for the anomalous composition of the dripwater. The slightly negative SI values that were occasionally observed indicate that further minor processes probably participate on the water formation.Cave speleothems grow from supersaturated dripwaters and store information about various karst processes along the water flow path. Anomalous non-saturated waters may occur if (1) rainfall water passes very rapidly through karst profile or if (2) two saturated waters of different compositions are mixed. The low mineralization close to saturation could be reached also as (3) result of calcite precipitating prior the water enters the cave. The hydrogeochemistry of four dripwaters in the Punkva Caves (Moravian Karst) was systematically studied for anomalous properties during one-year period. The drips are situated in a passage behind Přední Dóm Chamber (CP1 and CP2, 24 samples each), in Tunnel Corridor (TC1, 24 samples), and in Zadní Dóm Chamber (ZD1, 6 samples). The dripwaters CP1, CP2, and ZD1 show various flow regimes but very similar hydrogeochemical properties: electric conductivity (EC = 550–630 μS/cm), saturation (SIcalcite = 0.8–1.2), and Mg/Ca ratio (1000*(Mg/Ca) = 15–20). In contrast, the dripwater TC1 shows stable drip rate and EC = 275–350 μS/cm, SI = -0.1 to 0.3, and almost thrice as high Mg/Ca ratios as other drips. High and stable discharge of the drip TC1, combined with low EC, SI close to zero, and high Mg/Ca ratio indicate that a prior precipitation of calcite is responsible for the anomalous composition of the dripwater. The slightly negative SI values that were occasionally observed indicate that further minor processes probably participate on the water formation

Razvoj in preizkus nove kokile vrste 8k za ulivanje ingotov iz orodnega jekla

The traditional production of machinery and tools at ŽĎAS, a. s., and the increasing requirements placed on the final product, particularly those related to the internal quality of forgings, requires new technological measures for the ingot’s casting and solidification. The development and use of the new mould type 8K9.2 for tool-steel ingot casting has reduced the share of forgings with unacceptable quality. A substantial improvement has been achieved, especially in terms of the occurrence of defects, such as cavities and cracks in the ingot body.Tradicionalna proizvodnja strojev in orodij v podjetju ŽĎAS, a. s., in naraščajoče zahteve pri lastnostih končnega proizvoda, ki so povezane z notranjo kakovostjo izkovkov, so zahtevale nove tehnološke ukrepe pri litju in strjevanju ingotov. Razvoj in uporaba nove kokile vrste 8K9.2 za litje jeklenih ingotov sta zmanjšala delež ingotov nesprejemljive kakovosti. Pomembno izboljšanje je bilo doseženo pri pogostosti napak, razpok in votlin v notranjosti ingota

Six-membered nitrogen heterocycles - aromaticity and electron delocalization

All six membered nitrogen heterocycles are generally considered as delocalized systems with high extent of aromaticity. However, in our investigations we observed that the heterocycles bearing the azine grouping C=N-N=C (1,2,4-triazines and pyridazines) exhibit lower aromaticity, the N-N bond has a rather single-bond character and partly blocks the delocalization

Intramolekulární elektronová interakce dvou typů dikarbonylových slouočenin a jejich derivátů – elektrochemická a kvantově chemická studie

In the frame of studies of molecules with two redox centers, two isomeric monooximes derived from aryl-alkyl 1,2-diketones were electrochemically investigated. Whereas 1-phenyl-2-oxo-1-oximinopropane is reduced in acidic media according to the mechanism typical for oximes, that means by fou electrons yielding aminoketone, which is further reduced bielectronically under splitting of ammonia, its isomer 1-phenyl-1-oxo-2-oximinopropane is reduced to the stable 1-hydroxy-2-aminoolefine (enol form) and this corresponds to the reduction mechanism of benzil. It is surprising that the unsymmetric molecule behaves like the symmetric one. Basing on the electrochemical data and their correlation with quantum chemical calculations it was possible to explain this phenomenon