Nenad Tomasic

Nenad Tomasic
University of Zagreb · Department of Geology

PhD.

About

50
Publications
7,075
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
542
Citations

Publications

Publications (50)
Article
Five young soil profiles, formed from Miocene marls and argillaceous limestone, were investigated to determine changes in their clay mineralogy. Soil profiles were described, sampled, and their basic properties analyzed (particle size distribution, pH, cation exchange capacity (CEC), CaCO3 and organic C contents). The soils were classified accordin...
Conference Paper
Full-text available
Historical disposal sites of red mud can be found all around Europe, most notably at Sardinia, in Hungary, or at many locations in East-Southeast Europe. Red mud contains dominantly iron, aluminum, and silicon oxides, with races of various metals and compounds that can still be reprocessed if appropriate methods are applied. Some of the promising m...
Article
Full-text available
Tošići-Dujići bauxite deposit, situated in Dalmatian inlands, Croatia, contains minor remaining bauxite reserves. The deposit lies on Lower Eocene foraminiferal limestone and is covered by Upper Eocene Promina sediments. Bauxite samples were analyzed for textural, mineralogical, and geochemical features in order to determine absolute REE abundances...
Article
Full-text available
CaCO3 precipitation is physical-chemical basis of biomineral formation of hard tissue (shells, skeletons) in marine calcifying organisms (=biomineralization). Processes controlling biomineralization are still not fully clarified, so the study of influence of pH on basic processes of CaCO3 precipitation should contribute to better understanding of b...
Article
Full-text available
Gadolinite [REE2Fe2+Be2Si2O10] is a common mineral in certain types of rare element and rare earth element (REL-REE) pegmatites. Changes in pegmatite environment during and after gadolinite formation may be devised by studying its crystal-chemical properties and a thorough observation of microfeatures in the mineral matrix. Post-crystallization pro...
Article
Full-text available
In this study, the present status of the transboundary wetlands in Central Europe was evaluated using complementary experimental and statistical methods. Detailed characterization of the complex, subsaline/freshwater system in this study is aimed to be the contribution to the global wetland inventory. The distribution and behaviour of major and tra...
Conference Paper
Full-text available
The borehole Bunjani-59 is located in the Sava Depression in the Republic of Croatia, drilled about 10 km SE from the city of Ivanić Grad. The deepest cored rock material from the borehole, at a depth of 715 m, is made of igneous and metamorphic rocks like granites, gneisses and schists which belong to the crystalline basement of the Pannonian Basi...
Article
Full-text available
Interest in growing fruits and vegetables in private gardens is rising due to nowadays ecological awareness. Avoiding artificial fertilizers and plant protection products does not guarantee the absence of toxic substances, especially heavy metals in the soil and thus in the fruits harvested. Due to either geological bedrock weathering or environmen...
Article
Full-text available
Protonated titanate nanotubes (TiNT-H) were surface-modified with (3-aminopropyl)trimethoxy silane (APTMS) by a novel method suitable for the syntheses of large amounts of materials at a low cost. The usage of prepared nanotubes for polymer reinforcement was studied. Since the thermal stability of the nanofiller was important to preserve its functi...
Article
Full-text available
Abstract The aim of this study was to establish the fractionation of copper and zinc in a small apple orchard using the revised (four-step) Bureau Communautaire de Reference (BCR) sequential extraction procedure and assess their potential mobility in soil. Soil samples were collected at the depth of 10 cm to 25 cm, sixteen from the orchard and five...
Article
Full-text available
The adsorption properties in terms of cation exchange capacity and their relation to the soil and sediment constituents(clay minerals, Fe-, Mn-, and Al-oxyhydroxides, organic matter) were investigated in loess, soil-loess transition zone, and soil at four loess-soil sections in North-Western Croatia. Cation exchange capacity of the bulk samples, th...
Article
Full-text available
Purpose The paper describes an unusual finding of magnetic particles in stream sediments of the karstic Dobra River (Croatia). It aims to investigate the magnetic susceptibility properties of river sediments and to find links with their mineralogical and chemical composition. The goal of our research was to suggest the possible origin of magnetic p...
Article
Full-text available
Concentrations of Ag, Al, Ba, Cd, Co, Cr, Cu, Fe, K, Mn, Na, Ni, Pb, Sr, and Zn-isolated by sequential extraction steps from apple orchard soil-were analyzed by inductively coupled plasma-atomic emission spectroscopy and compared to the total amount of metal in soil determined by XRF. The extractable amount of each metal was calculated by the extra...
Article
The application of heterogeneous photocatalysis is described as an advanced oxidation process (AOP) for the degradation of the diazo reactive dye using immobilized TiO2 as a photocatalyst. Starting TiO2 solutions were prepared with and without the addition of polyethylene glycol (PEG) and TiO2 films were directly deposited on a borosilicate glass s...
Article
Data on the dehydration of pentahydroborite, CaB2O(OH)6·2H2O and nifontovite, Ca3B6O6(OH)12·2H2O from the Fuka mine, Japan are presented. Critical temperatures of the dehydration of the borates were determined by thermogravimetric analysis/differential thermal analysis measurements. The untreated mineral samples and their heating products were inve...
Article
Full-text available
Samples of metamict allanite-(Ce) originating from granite pegmatites were recrystallized by heating in air and under hydrothermal conditions. Recrystallization in air resulted in partial recovery of the crystal structure at 650 degrees C. Heating at higher temperatures resulted in decomposition of the allanite structure to a multiphase assemblage...
Article
Full-text available
Relics of the original samarskite structure were identified in a metamict ABO(4) mineral from Beinmyr pegmatite, Norway, using selected area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM). The chemical composition of the sample confirmed the affiliation to the samarskite group giving the general formula (RE...
Article
Structural stability of nanostructured titanates was investigated for further processing and possible applications. With the aim to investigate their mechanochemical stability we applied highenergy ball milling and studied induced phase transitions. Hydrogen titanates having two different morfologies, microcrystals and nanotubes, were taken into co...
Article
Full-text available
The content of major element oxides (Al2O3, SiO2, CaO, MgO, Fe2O3, P2O5, K2O, TiO2, and MnO) in soil surrounding the light metal factory (TLM), which was producing aluminium from 1937 till 1991, was investigated by EDXRF and XRD. The evaluation of a possible aluminium pollution linked to the industrial activity was studied by a comparison of soil a...
Article
Full-text available
Soils from an industrial zone in Garešnica, Croatia have been analysed by EDXRF and XRD. In the area surrounding two adjacent factories named 'Bakrotisak' and 'Croatia Protekt', thirty soil sites (depth 5-15 cm) were sampled in December 2007, together with five soil sites from the forest (control samples) situated 0.5 km away. The locality was sele...
Article
Full-text available
This paper presents a new treatment procedure applied on phosphogypsum transport water. Untreated transport water is highly acidic (pH 1.79), having fluoride content of 1540 mg/L and elevated values of phosphates (215 mg/L) and heavy metals (Fe=25.8 mg/L; Zn=5.7 mg/L; Mn=2.7 mg/L, V=1.7 mg/L). Neutralization/purification of the transport water was...
Article
High-energy ball milling has been employed for mechanochemical treatment of TiO2 and ZrO2, thus facilitated the solid-state reaction toward ZrTiO4. The ceramics with different degrees of porosity were prepared by 8 h sintering of thus prepared nanopowder precursor at 1100, 1200, 1300 and 1400 °C. The solid-state reaction was completed after sinteri...
Article
Fe-exchanged samples of zeolite A were prepared and their time-dependent properties during hydrothermal crystallization were studied by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), Rutherford backscattering (RBS) and 57Fe Mössbauer spectroscopy. The relative amounts of various iron spe...
Article
Full-text available
We report low field studies of the static magnetic susceptibility and torque measurements in the temperature range 2-330 K for the powder and crystalline CuTe(2)O(5) compound. We show that the observed extraordinarily large magnetic axis rotation below 20 K and small (nearly negligible), but highly anisotropic, low temperature susceptibility upturn...
Article
Full-text available
By applying combination of mechanochemical and thermal treatment important materials that could be used in sensor and semiconductor technology as well in catalysis are obtained. High energy ball milling was applied to prepare powder samples by treating mixture consisted a) of Cu and ammonium exchanged zeolite A and b) of CuO and ammonium exchanged...
Article
Full-text available
Metamict minerals are characterized by an amorphization of their crystal structure due to radiation damage, and they present an interesting challenge to the mineral and material scientist. The mechanisms of the crystal structure's metamictization and thermally induced recrystallization have been found not only to be of interest for solving mineralo...
Article
In high purity Y2O3 powders presence of small amount of erbium ions in cation sites was identified due to the luminescence bands observed by Raman spectrometer. The decrease of the luminescence intensity during high-energy ball-milling was explained. The mechanochemical processing induced the changes of Y2O3 microstructure introducing distortion of...
Article
Full-text available
Nioboaeschynite-(Y), with ideal chemical formula [(Y,Ln),Ca,Th](Nb,Ta,Ti,Fe)(2)(O,OH)(6), is a new member of the aeschynite group. It was discovered at the Bear Lake Diggings, Lot 9, concession X, Monmouth Township, Haliburton County, near Gooderham, Ontario, Canada. It occurs as subhedral crystals up to 1 cm in size, in association with apatite, a...
Article
A series of thin silicon films with different degrees of crystallinity were prepared by decomposition of silane gas highly diluted with hydrogen, in radiofrequency glow discharge. The crystallite size, shape, and the portion of crystalline phase were investigated by high-resolution transmission electron microscopy (HRTEM), selected area electron di...
Article
Full-text available
Important ceramics materials are prepared from aluminosilicate based precursors using novel methods, offering at the same time a better control over many important properties. Forsterite, due to its good refractoriness with melting point at 2163 K, excellent electrical insulation properties even at high temperatures, low dielectric permittivity, th...
Article
A series of ZrTiO4 (ZT) ceramics were prepared by sintering ball-milled precursor powders. Ceramics with homogenously dispersed micropores containing both low-temperature (ordered) and high-temperature (disordered) ZrTiO4 phases were achieved by sintering at 1400°C. The porosity and the morphology were modified by changing the sintering time. The i...
Article
Thin tin-oxide (SnOx) films were deposited by atmospheric pressure chemical vapor deposition (APCVD) and exposed to hydrogen plasma. The influence of such treatment on the films properties was investigated by X-ray diffraction (XRD), UV–visible spectroscopy, scanning electron microscopy (SEM), X-ray photoemission spectroscopy (XPS) and grazing inci...
Article
Positron lifetime (LT) measurements have revealed that in porous media the annihilation pattern is probably dominated by a near-saturation level trapping both for the positron and the positronium as well, which masks the contribution from the “free annihilation”, i.e., annihilation from delocalised positrons. In this work we compare positron lifeti...
Article
Full-text available
Powder mixtures of NH4-exchanged zeolite A and MgO, and of NH4-exchanged mordenite and MgO were used as starting materials in the synthesis of crystalline ceramic materials. Conventional ball milling was applied in order to amorphize NH4-exchanged zeolites, reduce the particle size of MgO, and produce a homogeneous mixture. Solid-state transformati...
Article
Full-text available
The metamict state and recrystallization of fergusonite in metamict natural samples were studied by thermal methods (TGA-DTA), X-ray powder diffraction (XRD), Raman spectroscopy (RS), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and electron microprobe (EPMA). Two metamict mineral samples of fergusonite were in...
Article
Nanocrystalline TiO2 powders were prepared by high-energy ball-milling using zirconia vial and balls. The changes of microstructure caused by material processing were studied using Raman spectroscopy, X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). The milling of the starting TiO...
Article
Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005.
Article
Using powder mixtures of NH4-exchanged zeolite A and MgO as starting materials, forsterite was obtained as the final phase. The preparation procedure consisted of two steps: high-energy ball milling and thermal treatment. Ball milling was applied to amorphise NH4-exchanged zeolite A, to reduce the particle size of MgO, and to mix these two componen...
Article
Full-text available
Meta-autunite from the pegmatite mineralization of Quintos de Baixo, Brazil was investigated. The total uranium content and elemental analysis yield the formula Ca(UVIO2)2–x(UVO2)x(H3O+)x(PO4)2·(6–x)H2O for the meta-autunite. The natural sample crystallizes tetragonally in the space group P4/nmm having unit cell parameters a = 6.990 (1) Å, c = 8.44...
Article
Full-text available
Metamict aeschynite-(Y) and polycrase-(Y) were studied by X-ray diffraction and Raman spectroscopy. To restore their crystal structure, the mineral samples were heated at various temperatures in air. The temperatures of 400, 500, 650, 800 and 1000°C were determined from TGA-DTA diagrams to be potentially important for structure restoration or chang...
Article
X-ray powder-diffraction investigation of a mineral sample from the Tiltvika granite pegmatite, Norway, shows the presence of a metamict phase with ferrocolumbite inclusions. On heating at 650°C for 21 hours, the diffraction pattern of petscheckite, a hexagonal mineral with idealized formula U4+Fe2+(Nb, Ta)2O8, is observed. The Tiltvika petscheckit...
Article
Full-text available
In production of thin films solar cells most common used material are silicon thin films. The efficiency of the solar cells could be considerably improved by applying Si material in different structural forms, since the absorption of light occurred in broader wavelength interval. As a result of various quantum effects the optical energy gaps alter...
Article
Full-text available
Carbon blacks are mostly used in car tyres, printing inks and plastics production. The properties of the rubber compound and vulcanized rubber (final product) are highly influenced by the primary particle size of carbon black. Beside this the shape of particle aggregation (structure) is also of great significance. In this work transmission electron...
Article
Important ceramics materials are prepared from aluminosilicate based precursors using novel methods, offering at the same time a better control over many important properties. Forsterite, due to its good refractoriness with melting point at 2163 K, excellent electrical insulation properties even at high temperatures, low dielectric permittivity, th...
Article
Full-text available
Relics of the original samarskite structure were identified in a metamict ABO4 mineral from Beinmyr pegmatite, Norway, using selected area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM). The chemical composition of the sample confirmed the affiliation to the samarskite group giving general formula (REE0.322...

Network

Cited By

Projects

Project (1)
Project
The project aims to determine the provenance of the Upper Miocene sandstones in the Croatian part of the Pannonian Basin System (PBS) and unravel diagenetic changes that occurred during the burial of the sediments. The sandstones were deposited in brackish and local freshwater lacustrine environments as prograding delta facies in time of the Central Paratethys isolation and Lake Pannon evolution, when thermal subsidence played a considerable role in the basin post-rift phase during the Late Miocene. These sandstones represent the largest reservoirs of oil and gas in Northern Croatia today and are thus of major interest to the petroleum industry. The intent of the study is to petrographically, mineralogically, chemically and petrophysically examine the sandstones from the selected exploration wells of the Sava and Drava Depressions that represent the two largest depressions in the North Croatian Basin as a Croatian part of the PBS. The analysis will provide a detailed composition of the clastic sediments and their parameters that will yield new insights into the initial source area, tectonic regime, weathering and pathways of the detritus, as well as information on the diagenetic changes that can help to improve depositional models and possibly predict sediment properties within the basin. Special emphasis will be placed on the analysis of heavy mineral associations, whole-rock chemistry, as well as single-grain analysis and clay mineralogy (types of clay present in pore system). The main purpose is examining whether the Upper Miocene sandstones of the Sava and Drava Depressions can be correlated, in particular based on provenance and appropriate diagenetic processes that can affect the reservoir quality. Past research did not focus on a detailed examination of the Upper Miocene sandstone provenance specifically from deep wells. Modifications caused by diagenesis in the sandstones have also never been interpreted before. Therefore, this project will provide a better understanding of the history of the sediments from the initial erosion of their parent rocks to the final burial. The project will ensure the precise characterization of the main reservoir rocks from the Late Miocene and their possible correlation in the Croatian and adjacent parts of the PBS which is especially crucial to further geological exploration of hydrocarbons in this area.