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1.
Preparation of filter aids based on diatomites 总被引：1，自引：1，他引：1
Sanja Martinovic Milica Vlahovic Tamara Boljanac Ljubica Pavlovic 《International Journal of Mineral Processing》2006,80(2-4):255-260
Two major deposits of diatomaceous earth (diatomite) in the region of the Balkan Peninsula, the Kolubara basin (Serbia and Montenegro) and the Vesje deposit (Former Yugoslav Republic of Macedonia), were selected for detailed investigation of their possible application in preparation of beer filter aids. Chemical, mineralogical and structural properties of diatomite samples were analyzed with the aim of predicting the filtration efficiency. Results of beer filtering compounds preparation are presented in this paper. The parameters of crushing, drying, calcination and classification are also defined. Beer filtration tests proved diatomites to be satisfactory and not causing any degradation of filtration process or beer quality. Technological flow scheme for obtaining the beer filter aids is proposed in the paper. 相似文献
2.
Nenad Marić Sanja Mrazovac Kurilić Ivan Matić Stanko Sorajić Jelena Zarić 《Environmental Earth Sciences》2014,72(2):525-534
This paper provides insight into the quality of groundwater used for public water supply on the territory of Kikinda municipality (Vojvodina, Serbia) and main processes which control it. The following parameters were measured: color, turbidity, pH, KMnO4 consumption, TDS, EC, NH4 +, Cl?, NO2 ?, NO3 ?, Fe, Mn, total hardness, Ca2+, Mg2+, SO4 2+, HCO3 ?, K+, Na+, As. The correlations and ratios among parameters that define the chemical composition were determined aiming to identify main processes that control the formation of the chemical composition of the analyzed waters. Groundwater from 11 analyzed sources is Na–HCO3 type. Intense color and elevated organic matter content of these waters originate from humic substances. The importance of organic matter decay is assumed by positive correlation between organic matter content and TDS, HCO3 content. There is no evidence that groundwater chemistry is determined by the depth of captured aquifer interval. The main processes that control the chemistry of all analyzed water are cation exchange and feldspar weathering. 相似文献
3.
Sanja Mrazovac Kurilić Staletović Novica Abulsba Khalil Salem Dagali Khaled Salem 《Water Resources》2019,46(6):861-870
Water Resources - This paper presents the results of the groundwater quality assessment, on the Serbian Danube, Sava and Morava River water area, for irrigation purposes. The analysis was done at... 相似文献
4.
This study presents a review of recently recorded instability phenomena on the flysch slopes of Istria, Croatia. The northeastern part of the Istrian Peninsula, the so-called Gray Istria, is built of Paleogene flysch deposits, where instability phenomena are frequent and where a large number of landslides, with significant consequences, have been recorded over the past 35 years. Based on field investigations conducted for the purpose of remedial study design, a database of these landslides was created. An investigation of the documented landslides and their elements found some common features that enabled general conclusions about the conditions and causes of landslide occurrence. In total, 19 documented landslides have been analyzed as individual phenomena, and from the results of these analyses, general conclusions were drawn about sliding conditions and the main triggering factors. Geological conditions and processes on slopes where landslides occurred are shown in detail, and geotechnical properties have been systematically represented. The sliding conditions and dimensions of four recent landslide occurrences, specifically by type, have been described in detail and analyzed. 相似文献
5.
The geothermal waters of the first and the shallowest groundwater system of the Province of Vojvodina in northern Serbia, south part of the Pannonian Basin, are characterized by elevated temperatures (between 25 and 85 °C) and elevated gas content (above 1 Nm3/m3) with a high methane content (average about 94% of total gases). These methane-containing waters are particularly abundant in the Central part of the province between Danube and Tisa rivers. Dominant ions in these waters are sodium and bicarbonate, but the waters also contain significant amounts of calcium, magnesium, potassium, chloride, and ammonium. Components that are of balneological significance include iodine, bromine, fluorine, strontium, lithium, barium, and metasilicic and metaboric acids. Based on statistical analysis, a strong positive correlation is generally observed in about 9.2% cases. A slightly lower correlation appears in about 42.2%, and negative correlation coefficient appears in about 48.6% cases. The dendrogram of the cluster analysis built on the wells shows three main groups. There is the cluster of (Na+)aq, (Cl−)aq and (HCO3−)aq. The second aggregation is (NH4+)aq/(NH3)aq. The third group includes (Mg2+)aq, (Ca2+)aq, (Fe3+)aq, (Sr2+)aq, (Pb2+)aq, and (Zn2+)aq. 相似文献
6.
Desert varnish of pristine sandstone and petroglyph surfaces from Takabart Kabort (Naturalistic Bubaline Art School) and Alamas (Tanzina Art School) can be well classified by their (SiO2+Al2O3):MnO2, Al2O3:SiO2, and P2O5:CaO ratios. Specific ratios are due to the occurrence of clay minerals like illite, kaolinite, smectite, and feldspar, quartz, carbonates like calcite and dolomite, manganese oxyhydroxides, and apatite. Their occurrence corresponds to the local origin and composition of the primary aeolian material.
In general, the analyzed desert varnish shows lamination patterns characterized by alternating MnO2-rich and -poor layers (25 wt% MnO2) at rather constant iron oxyhydroxide content (6 wt% Fe2O3). Varnish on non-engraved surfaces exhibits three MnO2-rich layers, whereas varnish-coated petroglyphs reveal minor lamination patterns corresponding to the dating of petroglyphs by rock art. The older Naturalistic Bubaline Art School petroglyphs (about 6–4 ka BP) and the younger Tazina Art School petroglyphs (about 3.8–3 ka BP) contain only two and one MnO2-rich layer, respectively. It is assumed that the occurrence of such microlaminations is caused by climate changes in North Africa. Three humid periods are discerned from the Terminal Pleistocene to Holocene in the literature. Such periods are suitable to induce manganese accumulation by biotic and abiotic processes. Accordingly, the distinct lamination patterns gained from this study verify the dating of petroglyphs by rock art. From another point of view, classification of the above petroglyphs may be provided by analyses of microlaminations independently on cultural historical aspects. 相似文献
7.
Prediction of landslide movements with practical application for landslide risk mitigation is a challenge for scientists. This study presents a methodology for prediction of landslide movements using random forests, a machine learning algorithm based on regression trees. The prediction method was established based on a time series consisting of 2 years of data on landslide movement, groundwater level, and precipitation gathered from the Kostanjek landslide monitoring system and nearby meteorological stations in Zagreb (Croatia). Because of complex relations between precipitations and groundwater levels, the process of landslide movement prediction is divided into two separate models: (1) model for prediction of groundwater levels from precipitation data and (2) model for prediction of landslide movements from groundwater level data. In a groundwater level prediction model, 75 parameters were used as predictors, calculated from precipitation and evapotranspiration data. In the landslide movement prediction model, 10 parameters calculated from groundwater level data were used as predictors. Model validation was performed through the prediction of groundwater levels and prediction of landslide movements for the periods from 10 to 90 days. The validation results show the capability of the model to predict the evolution of daily displacements, from predicted variations of groundwater levels, for the period up to 30 days. Practical contributions of the developed method include the possibility of automated predictions, updated and improved on a daily basis, which would be an important source of information for decisions related to crisis management in the case of risky landslide movements. 相似文献
8.
Jelena?Radoni?Email author Nata?a?Jov?i? Gavanski Miroslav?Ili? Sr?an?Popov Sanja?Bati??O?ovaj Mirjana?Vojinovi? Miloradov Maja?Turk Sekuli? 《Stochastic Environmental Research and Risk Assessment (SERRA)》2017,31(9):2201-2213
The paper presents the assessment of emission sources and health risk of 16 PAHs in the city of Novi Sad, Serbia, with developed oil, food, chemical and cement industry. Although the observed region has been previously studied with regard to the occurrence of PAHs in ambient air, the sources of emission and health risk using multivariate statistical methods have never been studied before. The research was conducted during the heating and non-heating periods at three sampling sites located in industrial, residential and high-traffic area. The samples were collected by high-volume air sampler and analysed using the GC/MS system. The data were processed using the positive matrix factorization (PMF) and cluster analysis. To assess the cancer-risk of PAHs, potency equivalency factor approach was used. The results of PMF analysis have indicated that significant sources of PAH emissions are industrial processes and diesel combustion during the non-heating, and coal combustion, heating plants and diesel combustion during the heating season. Cluster analysis of experimental data has confirmed the results obtained using the PMF method. Estimated values of lifetime lung cancer risk were higher than those set by the World Health Organization and US Environmental Protection Agency which indicates that cancer risk due to exposure to PAHs in ambient air exists in both time periods on the territory of Novi Sad. 相似文献
9.
Ivar R. Lokhorst Sjoukje I. de Lange Gerard van Buiten Sanja Selaković Maarten G. Kleinhans 《地球表面变化过程与地形》2019,44(14):2922-2935
Landscape experiments of fluvial environments such as rivers and deltas are often conducted with live seedlings to investigate effects of biogeomorphological interactions on morphology and stratigraphy. However, such experiments have been limited to a single species, usually alfalfa (Medicago sativa), whereas important environments in nature have many different vegetation types and eco-engineering effects. Landscape experimentation would therefore benefit from a larger choice of tested plant species. For the purpose of experimental design our objective was to identify fast-germinating and fast-growing species and determine their sensitivity to flow conditions during and after settling, their maximum growth, hydraulic resistance and added bank strength. We tested germination time and seedling growth rate of 18 candidate species with readily available seeds that are fast growing and occur at waterlines, plus Medicago sativa as a control. We selected five species that germinate and develop within days and measured properties and eco-engineering effects depending on plant age and density, targeting typical experimental conditions of 0–0.3 m/s flow velocity and 0–30 mm water depth. Tested eco-engineering effects include bank strength and flow resistance. We found that Rumex hydrolapathum can represent riparian trees. The much smaller Veronica beccabunga and Lotus pedunculatus can represent grass and saltmarsh species as they grow in dense patches with high flow resistance but are readily erodible. Sorghum bicolor grows into tall, straight shoots, which add significantly to bank strength, but adds little flow resistance and may represent sparse hardwood trees. Medicago sativa also grows densely under water, suggesting a use for mangroves and perhaps peat. In stronger and deeper flows the application of all species changes accordingly. These species can now be used in a range of landscape experiments to investigate combined effects on living landscape patterns and possible facilitation between species. The testing and treatment methodology can be applied to new species and other laboratory conditions. © 2019 The Authors. Earth Surface Processes and Landforms Published by John Wiley & Sons Ltd. © 2019 The Authors Earth Surface Processes and Landforms Published by John Wiley & Sons Ltd © 2019 The Authors Earth Surface Processes and Landforms Published by John Wiley & Sons Ltd. 相似文献
10.
Lipid classes in a small, eutrophicated salty lake (Rogoznica Lake, middle Adriatic), which is often subject to appeareance of anoxic conditions, were analyzed at the end of winter (March) and in summer (July) 2008. The results are supported with DOC, POC, phytoplankton, temperature, salinity and oxygen data. During both March and July massive, diatom blooms were recorded with maximum values at 5 m depth. Total lipids were found at high concentrations that were similar for the samplings in two months. Total particulate lipids dominated the pool, and showed large variations from 46.37 to 369.88 μg/l, with the highest concentration observed in the bottom anoxic layer in March. The variations for dissolved lipids were smaller and ranged from 44.82 to 124.35 μg/l. Opposite to lipids, DOC values increased 1.5 times between the two samplings, from the value of average 0.95 mg C/l in March to the average value of 1.44 mg/l in July. Conformingly with diatom blooms, POC was found in July at high concentrations (0.28–1.50 mg C/l), contributing to total organic carbon up to 46%. The distribution of organic carbon and lipids showed the tendency of accumulation toward deeper layers. The characterization of individual lipid classes revealed the dominance of phospholipids, indicating that the lipids in the lake mainly originated from the photosynthetically active phytoplankton community, which is sustained by high production of oxygen (oxygen saturation up to 200%). Low contribution of neutral lipids in the particulate fraction points to high availability of nutrients for present phytoplankton community. Lipid breakdown indices were found at significantly higher concentrations in March compared to July. Sea surface microlayer, the hydrophobic boundary, appeared to be generally lipid depleted in comparison to the sub-surface water. Qualitative analysis of sulfolipids revealed the potential of the lake for the occurrence of chemical interaction of sulfur with present organic matter. 相似文献