Mining activities have resulted in the existence of dumps, which generally present a perpetual danger of moving and transforming toxic elements. The experimental study was carried out in Nizna Slana ...(Slovakia) where the main source of emission was the iron-ore mining–processing factory focused on siderite mining. Siderit from Nizna Slana is highly ferrous with an increased level of the Mn content. Among the undesirable impurities on the deposit are mainly As, S, Pb, and Zn. According to the environmental regionalization of the Slovak Republic, the surveyed area represents a region with a slightly disturbed environment. The BIOLOG® Eco plates method was used for ecotoxicological evaluation of contaminated soils, where soil enzymes (acidic and alkaline phosphatase and urease) were also monitored in soils and soil contamination was evaluated according to Hakanson (1980). Based on the results obtained, it can be concluded that the content of Hg, Cd, Cr, Cu, As, Fe, Mn, and Mg is above the toxicity level. As, Fe, Mn, and Mg are the most serious pollutants in the area under investigation, and their pronounced excess indicates contamination, where harmfulness and toxicity can be expected. Based on the evaluation of the contamination factor and the degree of contamination, the soils in the emission field of old mining works are very highly to slightly contaminated with heavy metals. The experimental results in the real environment showed that the activity of soil enzymes showed considerable differences, and, regarding the functional diversity of soil microorganisms, we have not seen significant spatial variability.
Al-Si/Al-Mn composites are commonly used in aluminum heat exchangers. Improving their corrosion resistance is the key for prolonging their service life and reducing their costs. In this paper, an ...artificial salt spray corrosion test was adopted in accordance with the ASTM G85 standard to evaluate the atmospheric corrosion resistance of Al-Si/Al-Mn composites. The corroded samples were tested with electrochemical impedance spectroscopy (EIS). Microstructure evolution and their corrosion mechanism were discussed after the use of OM, SEM, EPMA and XRD. The results showed two corrosion mechanisms, including the pitting-induction mechanism and intergranular-development mechanism: pitting is induced by the destruction of the passive film as Cl– is adsorbed at the defects, while the corrosive medium in the pitting pores expands along the grain boundaries where eutectic Si is enriched. A corrosion process can be divided into three periods: the pitting-induction period, pitting-propagation period and matrix-corrosion period. The equivalent circuit models established sequentially were consistent with the actual macroscopic and microscopic observations.
The contribution deals with an evaluation of atmospheric deposition monitoring in 2001–2009 which was realised in the vicinity ofsiderite mining and processing works. Besides of gaseous emissions the ...works also produced the solid compounds of iron oxides and otherheavy metals. The iron ore plant worked up to August 2008. The atmospheric deposition (wet and dry) was determined by the modified bulkdeposition methodology. The samples were collected from seventeen monitoring sites, which are located maximally up to 8 km from the mainpollution source. Together with the deposition fluxes of heavy metals (Fe, Mn, Zn, Pb, Cu,Cr, Cd, As), the mineralogical composition,dispersion and size characteristics of solid particles were studied in selected samples. The volume content of respirable solid particles withthe diameter under 5 μm was from 6.7 to 13.2 %. Nanoparticles with the average hydrodynamic diameter in the interval of 242–558 nm werefound. High values of the deposition (median) of iron - 4111 mg.m-2.year -1, manganese - 236.6 mg.m-2.year -1 and especially toxic arsenic -8.05 mg.m-2.year -1 were measured in the area of Nižná Slaná in the years 2001–2008 and compared with other areas. A correlation betweenemissions of solid pollutants in particular years and the deposition for these metals was observed. In 2009, after shutdown of the works,a decrease of values at the most contaminated sites of deposition by arsenic, manganese and iron about 90 % was recorded. Sucha significant change was not recorded for other studied metals.
Guilan, a well-known province in rice production in Iran, has been facing water shortage and water degradation. In order to study the effects of salinity stress as well as water stress on rice a pot ...experiment was conducted at Rice Research Institute of Iran. Five water salinity levels: fresh water (EC = 1 dS m
), 2, 4, 6 and 8 dS m
and five irrigation regimes: continues flooding, Alternative Wetting and Drying (AWD), intermittent irrigation at 100, 90 and 80 percent of field capacity (FC) were considered as irrigation treatments. The results showed severe effects of water and salinity stresses on rice yield and yield components. Fresh water produced the highest yield, 18.57 gr pot
, whereas, the yield in salinity levels of 2, 4, 6 and 8 dS m
were 13.78, 5.78, 3.61 and 0.74 gr pot
, respectively, with the yield losses of 25, 70, 80 and 97%, respectively. Intermittent irrigation at FC produced the highest yield. The yield increased 8 and 13% in AWD and intermittent irrigation at FC treatments respectively, while it decreased 8 and 27% in intermittent irrigation at 80 and 90% of FC treatments as compared with continues flooding treatment. The highest yield with application of intermittent irrigation at FC was valid only in water salinity less than 4 dS m
. When water salinity was higher than 4 dS m
all irrigation methods gave the same yield. This study showed that the best method to use saline water was intermittent irrigation at FC with EC = 2 dS m
. In case of more salinity, mixing fresh and saline water and intermittent irrigation can mitigate the severe effects of salinity on rice.
Provinca Guilan v Iranu, ki je poznana po pridelavi riža se sooča s pomanjkanjem vode in slapšanjem njene kakovosti. Z raziskovanje učinka slanosti in vodnega stres na riž je bil izveden lončni poskus na Inštitutu za preučevanje riža v Iranu (Rice Research Institute of Iran). Uporabljeno je bilo pet slanostnih stopenj vode: sladka voda (EC = 1 dS m
), 2, 4, 6 in 8 dS m
in pet režimov namakanja: stalna poplavljenost, izmenično namakanje in osuševanje (AWD), in periodično namakanje pri 100, 90 in 80 procentni poljski kapaciteti (FC). Izsledki so pokazali močne učinke solnega in vodnega stresa na pridelek riža in njegove komponente. Pridelek je bil največji v sladki vodi, 18.57 g/lonec, medtem ko so bili pridelki pri slanostih 2, 4, 6 in 8 dS m
13.78, 5.78, 3.61 in 0.74 g/lonec, z izgubo pridelka 25, 70, 80 in 97 %. Periodično namakanje pri poljski kapaciteti je dalo največji pridelek. Pri izmeničnem namakanju in osuševanju se je pridelek povečal za 8 in periodičnem namakanju za 13 %, vendar se je v primerjavi s postopkom stalne poplavljenosti zmanšal za 8 in 27 % pri izvedbi tretmajev pri 80 in 90 % poljski kapaciteti. Največji pridelek pri periodičnem namakanju pri poljski kapaciteti je bil dosežen samo pri slanosti vode manj kot 4 dS m
. Če je bila slanost vode večja, so dali vsi postopki namakanja enak pridelek. Raziskava je pokazala, da je najboljši način periodičnega namakanja s slano vodo pri poljski kapacite s prevodnostjo vode za namakanje 2 dS m-1. V primeru večje slanosti je potrebno izmenično namakati s sladko in slano vodo, da se izognemu velikemu učinku slanosti na pridelek riža.
The distribution and communities of two annual grasses Crypsis aculeata and Heleochloa schoenoides were studied in Slovakia during 2003-2007. Herbarium and field data were used to reconstruct the ...occurrence of both taxa. A strong decline in C. aculeata localities was observed. This was mainly due to the destruction of periodically flooded saline habitats. By contrast, the occurrence of H. schenoides was changed only slightly. This species survives in secondary habitats (rural roads, field margins, field depressions). Point maps of historical and recent distribution are presented. Halophile vegetation of Crypsis aculeata and Heleochloa schoenoides has been sampled with the adapted Braun-Blanquet method. All collected relevés have been classified using the JUICE software. The results showed that the Crypsidetum aculeate Wenzl 1934 community is missing now in Slovakia, but Heleochloetum schoenoidis (Soó 1933) Topa 1939 was still recorded at a few sites. However, the community contained many ruderal plant species.
Raziskave razširjenosti dveh enoletnih trav Crypsis aculeata in Heleochloa schoenoides smo raziskovali na Slovaškem med letoma 2003 in 2007. Za rekonstrukcijo pojavljanja obeh vrst smo uporabili herbarrijske in terenske podatke. Opazili smo močno upadanje števila nahajališč, kjer se pojavlja C. aculeata. Razlog je predvsem uničenje periodično poplavljenih slanih rastišč. Nasprotno pa se je pojavljanje vrste H. schenoides le malo spremenilo. Vrsta lahko uspeva tudi na sekundarnih rastiščih (kolovozi, robovi njiv, uleknine na njivah). Historično in recentno razširjenost smo prikazali na točkovnih kartah. Halofilno vegetacijo vrst Crypsis aculeata in Heleochloa schoenoides smo vzorčili s prilagojeno Braun-Blanquetovo metodo. Vse popisno gradivo smo klasificirali s programom JUICE. Rezultati so pokazali, da asociacije Crypsidetum aculeate Wenzl 1934 na Slovaškem ne najdemo več, medtem ko je bila asociacija Heleochloetum schoenoidis (Soó 1933) Topa 1939 najdena na nekaj rastiščih, vendar se v njej pojavljajo številne ruderalne rastlinske vrste.
In this study, the FRIER rainfall-runoff model with distributed parameters was developed to assess changes in runoff and water balance due to changes in land use and climate. The water balance was ...calculated at 3 levels: on the surface and in unsaturated and saturated zones. Six basins from the central and eastern parts of Slovakia were selected on the basis of their similar size, but different topography, land use, soil texture and climate: the upper Hornad, the upper Hron, the Poprad, the Rimava, the Slana and the Torysa River basins. Model parameters were estimated using data from the period from June 1998 to May 2000 in daily time steps. The differences and similarities of the hydrologic processes in individual basins were investigated during the calibration period. Several scenarios of changes in land use and two simple scenarios of changes in climate were developed to estimate the impact of these changes on water balance and runoff. The changes in the hydrological regime were compared and discussed.
Provedeno je istraživanje kojim su se ispitivali učinci prirodnih zeolita kao pročišćivača vode na učinkovitost uklanjanja teških metala iz podzemne slane vode koja se koristi za uzgoj mlađi ...Dicentrarchus labrax. Ispitano je pet koncentracija zeolita: 0 (Z0), 2,5 ‰ (Z2,5), 5‰ (Z5), 7,5 ‰ (Z7,5) i 10 ‰ (Z10). Mlađ s početnom tjelesnom masom od 1,53 ± 0,018 g su nasađene u 15 akvarija s gustoćom 10 jedinki/akvarij. Ribe su se hranile komercijalnom hranom (42% proteina i 12,34% lipida) dva puta dnevno (09:30 i 14:00), u udjelu od 5% tjelesne mase ribe, tijekom 42 dana. Evaluirani su rast, iskorištavanje hrane, preživljavanje i učinkovitost uklanjanja teških metala. Indeksi rasta i iskorištenja hrane postupno su se poboljšavali s povećanjem koncentracije zeolita, pri čemu su najznačajnije vrijednosti (P≤0,05) otkrivene sa skupinom Z10. Stopa preživljavanja značajno se smanjila u skupini Z10 pri usporedbi s kontrolom (Z0). Značajno povećanje koncentracije zeolita (P≤0,05) poboljšalo je učinkovitost uklanjanja teških metala iz uzgojne vode sa adsorpcijskom selektivnošću Pb˃Cd˃Fe˃Cu˃Zn. Nadalje, otkriveno je povećanje brzine detoksikacije teških metala u mesu ribe s povećanjem razine zeolita uz selektivnost uklanjanja Fe˃Cu˃Zn˃Pb˃Cd. Zaključno, može se reći da se prirodni zeoliti mogu učinkovito koristiti za smanjenje teških metala u onečišćenim vodama, a posljedično i u mesu ribe, uz poboljšanje performansi rasta ribe.
Provider: - Institution: - Data provided by Europeana Collections- Painter, designer and sculptor Domen Slana- All metadata published by Europeana are available free of restriction under the Creative ...Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Nestabilnost kanala bušotine predstavlja ozbiljan problem koji se najčešće javlja tijekom bušenja kroz šejl. Uzrok nestabilnosti šejla proizlazi iz njegovog mineraloškog sastava (osobito udjela ...minerala glina) i njegovih fizikalno-kemijskih karakteristika. Do sada su provedena brojna laboratorijska ispitivanja s ciljem definiranja osnovnih uzroka nestabilnosti šejla i utvrđivanja svojstava šejla koja utječu na njegovo ponašanje u kontaktu s vodenom fazom različitih isplaka. U tim ispitivanjima korišteni su uzorci šejla dobiveni procesom jezgrovanja ili krhotine šejla sakupljene na vibracijskim sitima, ali i različiti uzorci šejla iz površinskih kopova, te je teško usporediti dobivene rezultate. Provođenje opsežnih laboratorijskih ispitivanja i usporedba dobivenih rezultata moguća je upotrebom umjetno stvorenih uzoraka šejla (peleta) točno određenog mineraloškog sastava. U radu su opisana laboratorijska ispitivanja bubrenja peleta određenog mineraloškog sastava u inhibiranim isplakama.
Plutonic rocks intrusive into the late Paleozoic Tetelna Formation of southern Alaska are the underpinnings of the late Paleozoic Skolai arc of the Wrangellia Terrane. There are four groups of ...intrusive rocks within the Skolai arc: (1) Gabbro-diorite plutons that contain gabbroic to anorthositic cumulates along with a differentiated series of gabbros and diorites of basaltic to andesitic composition; (2) Silicic intrusions including tonalite, granodiorite, and granite; (3) Monzonitic to syenitic plutonic rocks of the Ahtell complex and related dikes and sills; (4) Fault-bounded bytownite anorthosite of uncertain age and association. These anorthosites may be related to post-Skolai, Nikolai Greenstone magmatism. The silicic rocks yield discordant U-Pb zircon ages of 290-320 Ma (early to late Pennsylvanian). Relative age relations suggest that the oldest intrusive rocks are the gabbro-diorite plutons, the youngest are the monzonitic rocks, and that the silicic rocks span this range. The gabbro-diorite plutons are similar to gabbroic plutonic rocks in modern and other ancient island arc complexes. They record the differentiation of calc-alkaline basalt to andesite by the fractionation of plagioclase, pyroxene, olivine, and Fe-Ti oxides. The silicic rocks do not appear to be related to either the gabbros or the monzonites. They may represent partial melts of Skolai arc crust. The monzonitic rocks of the Ahtell complex have shoshonitic chemistry. Similar shoshonitic rocks are widespread in both the Wrangellia terrane and the neighboring Alexander terrane and intrude the contact between the two. In modern oceanic arcs, shoshonitic rocks are typically associated with tectonic instability occurring during the initial stages of subduction or just prior to or during termination or flip of an established subduction zone. The nature of any tectonic instability which may have led to the cessation of subduction in the Skolai arc is unclear. Possibilities include collision of the arc with a ridge, an oceanic plateau, another arc, or a continental fragment. One possibility is that the shoshonitic magmatism marks the late Paleozoic amalgamation of Wrangellia and the Alexander terrane. The scarcity of arc rocks predating the shoshonites in the Alexander terrane supports this possibility, but structural corroboration is lacking.
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