Aurivillius BaBi4Ti4O15 based compounds: Structure, synthesis and properties

The discovery of some Aurivillius materials with high Curie temperature or fatigue-free character suggests possible applications in high temperature piezoelectric devices or non-volatile ferroelectric random access memories. Furthermore, increasing concerns for environmental issues have promoted the study of new lead-free piezoelectric materials. Barium bismuth titanate (BaBi4Ti4O15), an Aurivillius compound, is promising candidate to replace lead-based materials, both as lead-free ferroelectric and high temperature piezoelectric. In this review paper, we report a detailed overview of crystal structure, different synthesis methods and characteristic properties of barium bismuth titanate ferroelectric materials

Barium titanate thick films prepared by screen printing technique

The barium titanate (BaTiO3) thick films were prepared by screen printing technique using powders obtained by soft chemical route, modified Pechini process. Three different barium titanate powders were prepared: i) pure, ii) doped with lanthanum and iii) doped with antimony. Pastes for screen printing were prepared using previously obtained powders. The thick films were deposited onto Al2O3 substrates and fired at 850°C together with electrode material (silver/palladium) in the moving belt furnace in the air atmosphere. Measurements of thickness and roughness of barium titanate thick films were performed. The electrical properties of thick films such as dielectric constant, dielectric losses, Curie temperature, hysteresis loop were reported. The influence of different factors on electrical properties values was analyzed

Electrical Characterization and Impedance Response of Lanthanum Doped Barium Titanate Ceramics

The dielectric permittivity and dissipation factor of La-doped and undoped BaTiO3 were investigated as a function of frequency and temperature. The impedance response was used to study the electrical properties of La-doped BaTiO3 over the temperature range from room temperature (RT) to 350 degrees C. La-doped and undoped BaTiO3, obtained by a modified Pechini method, were sintered in air at 1300 degrees C for 2 and 16 hours. The impedance spectra were analyzed in terms of equivalent circuits involving resistors, capacitors and constant phase elements (CPE). The most suitable electrical circuit for the interpretation of experimental results is found to be the equivalent circuit consisting of resistors and CPE elements which replace the capacitor elements. The contribution of grain boundary resistance to the total resistance of a system is remarkable at low temperature. Dielectric permittivity of doped BaTiO3 was in the range of 8000 to 12000 at 1 kHz and the dissipation factor was less than 1%

Effects of moulds on the safety and processing quality of Triticum aestivum

Wheat and wheat products are frequently subjected to mould infestations. Many of them are potential producers of various mycotoxins. Some of the consequences, due to the infestations by genus Fusarium and Alternaria, are mostly: yield loss, decrease of biological and technological quality, and unacceptable quality of infected kernels for the production and processing into human food because of the possible presence of mycotoxins. It is unknown whether and how the contaminated grains are distributed during milling into various flour streams and finished products. Wholegrain flours and related products contain all anatomic parts of kernels, including mycotoxins. It is a known fact that mycotoxins are resistant to thermal degradation, so they do not loose their toxicity during processing. Moulds from genus Fusarium spp. and Alternaria spp. synthesize mycotoxins, mostly zearalenon and ochratoxin A. The aim of the investigation was to examine mould contamination of wheat grain, as well as to identify the isolated species, especially those capable of producing toxins, and to determine their impact on technological quality, safety and sanitary condition of wheat. Six varieties of wheat, contaminated with moulds, were investigated. Each sample was separated manually into four fractions: sound kernels, black germ kernels, kernels infected slightly and those infected severely with Fusarium spp

Determination of inorganic compounds in drinking water on the basis of house water heater scale, part 1: Determination of heavy metals and uranium

The analysis of scale originated from drinking water on the house water heater, showed that scale is basically calcium carbonate that crystallizes hexagonally in the form of calcite. Scale taken as a sample from different spots in Belgrade – upper town of Zemun (sample 1) and Pančevo (sample 2) showed different configuration although it came from the same waterworks. That indicates either that the water flowing through waterworks pipes in different parts of the city is not the same or the waterworks net is not the same (age, maintaining, etc). All the elements which are dominant in drinking water (Ca, Mg, K, and Na), and which could be found in water by natural processes, are by their content far below the values regulated by law. The analysis also showed the presence of many metals: Ti, Pb, Zn, Cu Li, Sr, Cd, and Cr in the first sample, which are not found in the scale taken near Pančevo. The results obtained by calculating the mass concentration in drinking water on the basis of scale content, showed that both waters belonged to the category of low mineral waters. Contents of inorganic substances in these waters (117.85 mg/dm3 for sample 1 or 80.83 mg/dm3 for sample 2) are twice lower than the values predicted by the legislation. Gammaspectrometric analysis indicates the presence of radioactive elements – uranium and strontium which can influence human health

Procena potencijalnog zdravstvenog rizika usled prisustva toksičnih metala u vodi za piće iz individualnih bunara u selu Dubravica u Braničevskom okrugu

In order to verify the content of macro- and microelements in drinking water in the village of Dubravica in the Branicevo district, which has no centralized water supply system, an analysis of the water sampled from two individual wells was conducted using the indirect method recommended by Rajkovic and associates. Tests on the RDA and AAS showed that: Al, Fe, Cr, Pb and U were in concentrations higher than the values allowed by Regulations on the hygienic quality of drinking water. To determine the risk of the presence of toxic metals in the elevated concentrations, the assessment of short-term and long-term potential carcinogenic risks was conducted. Based on the results obtained in the tested water samples, it is noticed that the value of the coefficient of risk (CR) was less than 1 for all potentially toxic metals that were determined in drinking water, which implies that there is no short-term carcinogenic potential risk to human health. Based on the results of the long-term potential risk for the occurrence and development of cancer, the risk of getting cancer of Cr was identified in the inhabitants of the village that used potable water of the first sample. In case of Pb, a risk of developing cancer, concerning the first sample of drinking water, may occur in 44 out of 1000 people and regarding the second sample, in 183 out of 1000 people. Based on the calculated estimates of the long-term health risk related to the presence of U in drinking water, it can be seen that there is a health risk related to the use of both water samples. On the basis of the calculated estimates of the long-term health risk related to the presence of uranium in drinking water, it can be noticed that the use of both water samples may lead to the potential risk of developing cancer: in 24.5 inhabitants regarding the first water sample and in 10.3 out of 1000 inhabitants in the case of the second water sample.Da bi se proverio sadržaj makro- i mikroelemenata u vodi za piće u selu Dubravica u Braničevskom okrugu, koje nema centralizovan vodovodni sistem, izvršena je analiza voda koje su uzorkovane iz dva individualna bunara, indirektnom metodom preporučenom od strane Rajkovića i saradnika. Ispitivanja su pokazala da se: Al, Fe, Cr, Pb i U nalaze u koncentracijama višim od MDK vrednosti dozvoljene Pravilnikom o higijenskoj ispravnosti vode za piće. Da bi se utvrdila opasnost od prisustva toksičnih metala u povišenoj koncentraciji urađ ena je procena kratkoročnog i dugoročnog potencijalnog kancerogenog rizika. Na osnovu rezultata ispitivanja koji su dobijeni za ispitivane uzorke vode, ne postoji potencijalni kratkoročni kancerogeni rizik po zdravlje ljudi. Na osnovu rezultata dobijenih za dugoročni potencijalni rizik za pojavu i razvoj kancerogenih oboljenja, kod stanovnika sela koji koriste vodu za piće i uzorka izražen je rizik za nastajanje kancera od Cr. U slučaju Pb, rizik od pojave kancera u slučaju I uzorka vode za piće javlja se kod 44 od 1000 stanovnika, a u slučaju II uzorak kod 183 od 1000 stanovnika. Na osnovu izračunate procene dugoročnog zdravstvenog rizika od prisustva U u vodi za piće zapaža se da u slučaju konzumiranja oba uzorka vode postoji potencijalni rizik od nastajanje kancera: u slučaju I uzorka vode kod 24,5 stanovnika, a u slučaju II uzorka 10,3 stanovnika od 1000 stanovnika

SCADA SYSTEMS IN THE CLOUD AND FOG ENVIRONMENTS: MIGRATION SCENARIOS AND SECURITY ISSUES

This paper addresses scenarios and security issues when migrating SCADA systems to cloud and fog environments. Migration strategies to the cloud refer to different cloud infrastructures (public, private or hybrid) as well as selection of cloud service. Benefits of cloud-based SCADA systems mainly refer to improving economic efficiency. We further address migration risks, with regards to quality of service and cyber security. Challenges in security provisioning encompass security solutions, risk management and test environment. Finally, we address emerging evolution of SCADA toward fog computing, including the three-tier system’s architecture and security issues

Applying multi-criteria analysis for preliminary assessment of the properties of alginate immobilized Myriophyllum spicatum in lake water samples

The preliminary assessment of the properties of alginate immobilized aquatic weed Myriophyllum spicatum beads-MsAlg in a multi-element system of nine Serbian lakes water samples was done. Herein, the results obtained in the biosorption experiment with MsAlg contents of twenty-two elements analysed by inductively coupled plasma-optical emission spectrometry, biosorption capacity, element removal efficiency, total hardness (TH) and quality index of water (WQI) are presented. Scanning electron microscopy with energy dispersive X-ray spectroscopy was used for the characterization of M. spicatum and its beads. The study showed that aluminium, magnesium and strontium were adsorbed by MsAlg in the water samples from all examined lakes; barium and iron in the water samples from six lakes. The overall average efficiency of MsAlg in biosorption of elements was in the following order: Al > Ba > Sr > Fe > Mg (58.6, 51.7, 48.2, 23.9 and 17.7%, respectively). The increase of TH and WQI values after the biosorption was noticed in all studied lake water samples. The most significant correlations for pH were regarding the contents of B, Mg and Ca, whereas WQI was highly correlated to the contents of B and Mg, and pH. The complexity of the obtained data was explained by Cluster Analysis and Principal Component Analysis, which showed good discrimination capabilities between the water samples taken from different locations. Considering that the invasive M. spicatum is natural, widespread and that its immobilization is cheap and eco-friendly, presented findings could be helpful in further assessment of MsAlg beads for its potential use as biofilter

Analiza sadržaja makro- i mikroelemenata u vodi za piće iz vodovodne mreže grada Požarevca

This study aims at analysing physical, chemical and microbiological properties, and content of macro- and microelements in the water from the Požarevac city public water supply system. Analysis shows an increased content of Ca in drinking water, as a result of the position of Požarevac on the sediments of river terrace of accumulative character of t1 type, predominantly consisting of quartzite. The water from the public water supply is alkaline ('calcic', 'bicarbonate water') and very hard, due to the increased Ca content. Beside Ca, potassium and aluminium exceed the maximum contaminant level, while Pb and Cd are at the very limit. Calculated data show that there are no short-term health risks regarding elements exceeding allowed concentrations found in the public water supply system. Data analysis regarding long-term health risks shows that Cd present in drinking water poses the only relevant threat to human health. Cancer risk is present in 202 out of 1000 inhabitants using this water.Predmet ispitivanja bila je voda za piće iz vodovodne mreže Grada Požarevca, sa aspekta fizičko-hemijske i mikrobiološke ispravnosti i prisustva makro- i mikroelemenata. Ispitivanja su ukazala na povećanu koncentraciju Ca u vodi za piće kao posledica položaja Požarevca na sedimentu rečne terase akumulativnog karaktera t1, koja je pretežno sagrađena od kvarcita. Kao posledica povećane koncentracije Ca, voda iz vodovodne mreže je alkalnog karaktera ('kalcijumova', 'biokarbonatna voda') i veoma tvrda. Osim Ca, K i Al prevazilaze maksimalno dozvoljene koncentracije, dok se Pb i Cd nalaze na samoj granici. Proračunati podaci pokazuju rizik od unošenja elemenata koji se u vodi iz vodovodne mreže Grada Požarevca nalaze u vrednosti višoj od dozvoljene pravilnikom, ni za jedan metal ne postoji kratkoročni zdravstveni rizik po zdravlje ljudi. Analiza podataka o dugoročnom zdravstvenom riziku ukazuje da jedina realna opasnost postoji od prisustva Cd u vodi za piće. Rizik od pojave kancera prisutan je kod 202 stanovnika od 1000 stanovnika koji koriste ovu vodu za piće

Supplementary material for the article: Šoštarić, T. D.; Petrović, M. S.; Pastor, F. T.; Lončarević, D. R.; Petrović, J. T.; Milojković, J. V.; Stojanović, M. D. Study of Heavy Metals Biosorption on Native and Alkali-Treated Apricot Shells and Its Application in Wastewater Treatment. Journal of Molecular Liquids 2018, 259, 340–349. https://doi.org/10.1016/j.molliq.2018.03.055

Supplementary material for: [https://doi.org/10.1016/j.molliq.2018.03.055]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2152]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/2970