Band flattening in buckled monolayer graphene

The strain fields of periodically buckled graphene induce a periodic pseudo-magnetic field (PMF) that modifies the electronic band structure. From the geometry, amplitude, and period of the periodic pseudo-magnetic field, we determine the necessary conditions to access the regime of correlated phases by examining the band flattening. As compared to twisted bilayer graphene the proposed system has the advantages that: 1) only a single layer of graphene is needed, 2) one is not limited to hexagonal superlattices, and 3) narrower flat bandwidth and larger separation between flat bands can be induced. We, therefore, propose that periodically strained graphene single layers can become a platform for the exploration of exotic many-body phases.Comment: To appear in Physical Review

Leaching of chromium from chromium contaminated soil: Speciation study and geochemical modeling

Distribution of chromium between soil and leachate was monitored. A natural process of percolating rainwater through the soil was simulated in the laboratory conditions and studied with column leaching extraction. Migration of chromium in the soil is conditioned by the level of chromium soil contamination, the soil organic matter content, and rainwater acidity. Chromium (III) and chromium(VI) were determined by spectrophotometric method with diphenilcarbazide in acidic media. Comparing the results of chromium speciation in leachate obtained by experimental model systems and geochemical modelling calculations using Visual MINTEQ model, a correlation was observed regarding the influence of the tested parameters. Leachate solutions showed that the concentration of Cr depended on the organic matter content. The influence of pH and soil organic matter content is in compliance after its definition through experimental and theoretical way. The computer model - Stockholm Humic Model used to evaluate the leaching results corresponded rather well with the measured values

Impact of IT on organizations in modern conditions

Information technology, especially the internet, exerted strong influence on organizational systems. It has enabled flexibility and the establishment of decentralized and dispersed business organizations. Conception of the organization based on the principle of ‘integrated decentralization’ is the opposite of concentrated and centralized organizations that had dominated the traditional organizations of the past. Information technology has largely contributed to the establishment of integrated decentralized organization because companies have been able to decentralize their parts in the general area, and then to integrate them at a centralized level, with the establishment of specific functions for all decentralized areas. This paper further discusses the impact of IT on the design of organizations, as well as the place and role of man in the information society

Genotype and soil type influence on morphological characteristics, Yield and oil content of oil-flax

The three-year trial investigated the individual and the mutual interaction among three genotypes of oil-flax (Olin, Zlatko, Ljupko) and subtype of soil (chernozem with signs of gleyzation and chernozem on sandy loess) and their influence on morpho-physiological traits, yield and oil-flax oil content. The tallest stems (70.3 cm) had the Olin variety in agro-ecological conditions of Southern Banat region. Number of capsules per plant and number of grains per capsule was dependent on agroecological conditions in the investigated year. The largest number of capsules (68) per plant had the Zlatko variety, while the highest average grains number in the capsules (8.2) was at the Olin variety. The obtained values of the studied varieties for these two variables were not statistically significant. On average, the highest oil-flax seed yield gave the Ruben variety (1416.3 kg ha-1), which was higher for about 9.45% compared to the Ljupko variety, and 9.65% compared to the Olin variety. The highest oil content was at the Ljupko variety (41.1%). This value was higher by 1.21 rel.% compared to the Zlatko variety (40.6%), and 0.07 rel.% compared to the Olin variety (40.8%). Three-year average grains yield (Starcevo locality) was 1430.6 kg ha-1. The yield increasing at chernozem with signs of gleyzation compared to plants grown on chernozem on sandy loess (Devojacki Bunar locality) was 17%. On the other hand, the oil content in general was higher in this type of soil than on chernozem with signs of gleyzation (41.0% vs. 40.7%)

Supplementary data for article: Sakan, S.; Dević, G.; Relić, D.; Anđelković, I.; Sakan, N.; Đorđević, D. Risk Assessment of Trace Element Contamination in River Sediments in Serbia Using Pollution Indices and Statistical Methods: A Pilot Study. Environmental Earth Sciences 2015, 73 (10), 6625–6638. https://doi.org/10.1007/s12665-014-3886-1

Supplementary material for: [https://doi.org/10.1007/s12665-014-3886-1]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1701

External magnetic field-induced aggregation and sedimentation processes arising in magnetic fluids

The spectral analysis of external magnetic field influence on hydrothermally synthesized CoFe2O4, FeFe2O4, and MgFe2O4 nanoparticles in ferrofluid was presented. In order to control particle growth, stabilize particles against aggregation and enhance dispersibility in an aqueous medium, surface coating was achieved using citric and oleic acid, popular surfactants in preparation of magnetic particles for medical applications. New experimental settings were developed for the study of behavior of ferrofluids with the applied magnetic field strength in the range of 30-400 mT. Field-induced change of transmittance occurred and a precipitation of all studied samples was obtained. Contrary to the linear aggregates of colloidal CoFe2O4 and FeFe2O4, approximately spherical aggregates were observed in the case of MgFe2O4. The behavior of this kind of ferrites is in accordance with its soft magnetic nature. In all cases, the surface modification resulted in decreased dipole-dipole interactions between magnetic cores, and consequentially less precipitates were noticed. All citrate coated nanoparticles have shown stronger magnetic response in comparison to the oleate modified samples. The aggregation of nanoparticles potentially increases cytotoxicity although it is still unknown how aggregates formed in external magnetic field affect biological responses when ferrites are used in biomedical applications. Regarding non-linear clustering of MgFe2O4 suspensions, it can be concluded that its excretion from the organism could be likely easier and faster when used in diagnosis and/or therapy. Therefore, more attention should be paid to the low toxic MgFe2O4 for its medical application

Supplementary material for the article: Sakan, S.; Popović, A.; Anđelković, I.; Đorđević, D. Aquatic Sediments Pollution Estimate Using the Metal Fractionation, Secondary Phase Enrichment Factor Calculation, and Used Statistical Methods. Environmental Geochemistry and Health 2016, 38 (3), 855–867. https://doi.org/10.1007/s10653-015-9766-0

Supplementary material for: [https://doi.org/10.1007/s10653-015-9766-0]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1940

EVALUATION OF QUALITY OF SEMI-NATURAL GRASSLANDS OF CENTRAL SERBIA UPON PHYTOSOCIOLOGICAL AND NUMERICAL ANALYSIS

Abstract: The aim of this paper is to present a numeric-statistical model by which it is possible to evaluate the quality of the observed grassland upon floristic and vegetation assessment. Thanks to this new methodological approach, the impact of each individual plant species on overall quality of the grassland could be estimated. The main goal was to determine species which significantly determine the pastoral value of the grassland. The quality (pastoral value) of the grassland was calculated using the numerical values of quality index of each individual species of each relevé of the community. For testing this numerical method, the total of 11 relevés of 4 grassland communities of hilly-mountainous area of Mt. Kopaonik was used. Analyzed vegetation includes previously unpublished phytocenological relevés as result of our own field research. All analyzed relevés were obtained using the method of the Swiss-French phytocenological school. The results showed that the best and the worst quality were determined for the ass. Festuco-Brometum erectii, and the ass. Nardetum strictae, respectively. Species that highly contributed to good and bad quality of grassland were Arrhenatherum elatius, Festuca rubra, Dactylis glomerata, Trifolium repens, etc., and Carduus alpestris, Hieracium hoppeanum, Ornithogalum umbelatum, respectivel

Anthropometrische, kraft-, ausdauer-und flexibilitätsmerkmale männlicher elite-eiskletterer und sportkletterer

Objective: Purpose of this study was to compare elite male ice climbers and sport climbers for their anthropometry, muscular strength, endurance, and flexibility. Although there is a certain overlap between these two activities, sport climbing, which recently became an Olympic discipline, has been studied significantly more than the ice climbing. Hence, the second aim was to indirectly determine whether sport climbing training processes and nutrition can be beneficial for the ice climbing athletes. › Methods: 23 male ice climbers of the Ice Climbing World Cup 2010 in Saas Fee (Switzerland) who all reached the final round were compared to 23 elite male sport climbers, which refers to “on sight” climbing grade of VII+/6b (UIAA/French) or higher. Measurements included anthropometry, three different tests for flexibility, two for strength and two for endurance. › Results: Ice climbers have more fat in the trunk region (Fat%-T), have significantly less handgrip strength in both hands, as well as strength to mass ratio (SMR) of the dominant hand. In the test “foot raise”, ice climbers showed significantly less flexibility. › Conclusion: Results indicate that ice climbers have not only higher body fat percentage, probably as an adaption to cold environment but also lower strength and flexibility than sport climbers. With such data, we can conclude that sport climbing training protocols for development of strength, endurance and flexibility can be potentially beneficial to ice climbers.Ziel: Ziel dieser Studie war es, männliche Elite-Eisk letterer und Sportk letterer hinsichtlich ihrer Anthropometrie, Muskelkraft, Ausdauer und Flexibilität zu vergleichen. Das zweite Ziel war zu bestimmen, ob Trainingsprozesse und Ernährung auf der Grundlage von Untersuchungen an Sportk letterern auch für Eiskletterer von Vorteil sein können.›Methoden: 23 männliche Eisk letterer des Ice Climbing World Cup 2010 in Saas Fee (Schweiz), die alle in die Finalrunde kamen, w urden mit 23 männlichen Elite-Sportkletterern verglichen, die „on sight“ einen K lettergrad von V II+/6b (UIA A/French) oder hö-her aufw iesen. Die Messungen umfassten die Anthropometrie, drei verschiedene Tests für Flexibilität, zwei für K raft und zwei für Ausdauer.›Ergebnisse: Eisk letterer haben mehr Fett im Rumpf bereich (Fat%-T), signifikant weniger Handgriff kraft in beiden Händen sowie Kraft-zu-Masse-Verhältnis (SMR) der dominanten Hand. Eiskletterer zeigten deutlich weniger Flexibilität imHüftbereich.›Schlussfolgerung: Die Ergebnisse zeigen, dass Eisk letterer nicht nur einen höheren Körperfettanteil haben, wahrscheinlich als Anpassung an eine kalte Umgebung, sondern auch eine gerin-gere Kraft und Flexibilität als Sportkletterer. Sportkletter-Trai-ningsprotokolle können zur Entw ick lung von Kraft, Ausdauer und Flexibilität für Eisk letterer potenziell von Vorteil sein