Calcium oxide (CaO) itself, as cheap, highly active and easily available, is one of the most used solid catalysts for transesterification reaction of different oils and fats to biodiesel. A way to ...improve its catalytic activity is to increase its specific surface by preparing it in the nano–form. This paper gives an overview of the preparation of nano–sized CaO–based catalysts and their application in the biodiesel production. Various forms of nano–sized CaO–based catalysts have been employed in the biodiesel production like neat, doped and loaded CaO as well as waste material containing CaO. The modern technology based on the use of nano CaO–based catalysts aiming at high biodiesel yields will have further positive implications like simplicity, safety, economy and efficiency of biodiesel production. This overview proves the promising potentiality of nano CaO–based catalysts as solid catalysts in biodiesel production.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK
In comparison to the (Western) European tradition, the development of music theory in Serbia has been quite short. Milan Milovuk's works, dating from the 1860s, were the first published theoretical ...writings in Serbian. Nevertheless, this development was substantial, leading from basic music theory in Milovuk's pioneering works to an interdisciplinary field of research that is fully integrated into today's global map of the discipline. Through this expansion, the status reconfiguration of music theory in Serbia took place from propaedeutics to an autonomous scientific field. However, the transformation of the discipline was not the subject of scientific research until recently. The questions about the nature of a musical-theoretical work, on what basis and with what convictions it is carried out, what kind of knowledge it produces, and what the impact of that knowledge is can be considered an exception in music theory writings in Serbian. Likewise, the legitimisation of certain types of musical-theoretical work about the discipline as a whole or its relevant parts has only recently become represented in our scientific literature. In this article, I investigate the reasons for the indicated epistemological certainty of music theory in Serbia and study the traces of its disciplinary legitimation in both diachronic (historical-developmental) and synchronic (theoretical-conceptual and methodological-epistemological) perspectives.
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Since 2008, Jasna Veličković has been experimenting with and researching within the sound world of the magnetic field-the omnipresent, yet usually completely silent elements in human life. Her ...journey into the unknown started with an exploration of the sound produced by manipulating coils as parts of complex sound systems, including classical instruments as sound sources. A purely serendipitous event in 2013 led her to the discovery that magnets can also produce sounds when applied to coils in certain ways. This discovery ultimately resulted in the invention of the Velicon, the instrument which she has been composing for and performing on ever since. The investigations of the musical force of the magnetic field also led to the introduction of other seemingly silent objects as sound sources. In this article, I aim to investigate these works both from the diachronic and the synchronic perspective. The key questions will include: (1) mapping Jasna Veličković's referential worlds-an intricate encounter between music and science/technology, (artistic) experimentation, and electronic music-viewed from the composer's personal, Serbian, and 'global' perspective; (2) the nature of Veličković's creative process with regard to the reconfiguration of the relationship between composing, experimenting, and improvising; (3) the ramifications of Veličković's way of breaking loose from the conventional composer-performer-listener chain; and (4) analytical remarks on the prospects of musical structure within the magnetic sound.
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4.
Biodiesel production from non-edible plant oils BANKOVIC-ILIC, Ivana B; STAMENKOVIC, Olivera S; VELJKOVIC, Vlada B
Renewable & sustainable energy reviews,
08/2012, Volume:
16, Issue:
6
Journal Article
Peer reviewed
Because of biodegradability and nontoxicity biodiesel has become more attractive as alternative fuel. Biodiesel is produced mainly from vegetable oils by transesterification of triacylglycerols. From ...economic and social reasons, edible oils should be replaced by lower-cost and reliable feedstocks for biodiesel production such as non-edible plant oils. This paper reviews various methods for biodiesel production from common non-edible oils employing alcoholysis reactions. The aim of this paper is to present the possibilities of the use of non-edible oils into biodiesel production, to consider the various methods for treatment of non-edible oils and to emphasize the influence of the operating and reaction conditions on the process rate and the ester yield. The special attention is paid to the possibilities of optimization, kinetics and improvement of biodiesel production from non-edible oils.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK
Psychosocial risks represent a great challenge for safety and health protection at work in Europe. The purpose of this study has been to determine the relationships of psychosocial risks arising from ...work, stress, personal characteristics and burnout among physicians and nurses in the Emergency Medical Service (EMS).
We performed a cross-sectional study based on a questionnaire survey which contained the Copenhagen Psychosocial Questionnaire (COPSOQ) and Copenhagen Burnout Inventory (CBI).
A total of 88 physicians and 80 nurses completed the survey. Physicians demonstrated higher emotional (mean (M) ± standard deviation (SD) = 74.57±16.85) and cognitive (M±SD = 75.95±13.74) demands as compared to nurses. Both groups had high sensory demands and responsibilities at work, in spite of the low degree of their autonomy. The meaning of work, commitment to the workplace, and insecurity at work were high for both groups. Among all participants, stressful behavior and reactions were within the limits of low values (< 40) and coping strategies showed high values (> 60). Personal and patient-related burnout was high for both groups, where physicians were significantly affected by work-related burnout. The influence at work, degree of freedom at work, social support, sense of coherence, mental health, and problem-focused coping are negatively related to work-related burnout.
Based on personal factors and coping styles, emergency physicians and nurses are representing a self-selective professional group that meets high work demands, great responsibility, strong commitment and insecurity at work. Burnout of physicians and nurses in the EMS tends to be ignored, although it has severe consequences on their mental and general health. Med Pr 2017;68(2):178-178.
Biodiesel production from corn oil: A review Veljković, Vlada B.; Biberdžić, Milan O.; Banković-Ilić, Ivana B. ...
Renewable & sustainable energy reviews,
08/2018, Volume:
91
Journal Article
Peer reviewed
This paper deals with biodiesel production from corn oil as a feedstock via the transesterification and esterification reactions. To date, corn oil has not been considered a viable biodiesel ...feedstock because of its high edible value and relatively high price, but some industrial corn processing co-products, such as corn germ and dried distillers grains with solubles (DDGS), have potential for this application after the extraction of corn distillers oil (CDO). Here, after brief discussion of the issues related to corn botany, cultivation, and use, as well as the corn germ and oil composition, properties and use, the methods of corn processing for germ and DDGS recovery are presented. In addition, the mechanical and solvent extraction techniques for oil recovery from whole ground corn kernels, germs, and DDGS are considered. Furthermore, biodiesel production from corn oil, waste frying corn oil, and CDO is critically analyzed. It is expected that further investigation will be directed toward developing simpler, more effective and energy-saving technologies for biodiesel production from corn oil-based feedstocks, especially from CDO. The integration of biodiesel production directly into corn-based ethanol production will advance the overall economy of industrial plants. Furthermore, the fuel properties, performances and exhaust gas emissions of corn-based biodiesel and its blends with diesel fuel are discussed, taking into account the biodiesel quality standards. Finally, issues related to the environmental and socio-economic impacts of corn-based biodiesel production and use are also tackled.
•Oily co–products of industrial corn processing are promising biodiesel feedstocks.•“Green” oil extraction methods will improve corn oil recovery.•Simpler, more efficient and energy–saving corn-based biodiesel technology is needed.•The integrated reactor/separation process of biodiesel production is more efficient.•Biodiesel production can be integrated in the corn-based ethanol production.
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Monitoring and forecasting of chemical and physicochemical parameters of groundwater is an important factor in quality control and water management. In order to optimize these processes, the initial ...purpose of this paper was to identify sources of pollution and predict spatial changes in groundwater quality. Patterns of spatial changes in groundwater quality in the Danube river basin (Serbia) have been identified using multivariate statistical techniques. The results of the applied cluster analysis are the indicators of the existance of two spatial clusters. The principal component/factor analysis (PCA/FA) has shown that beside natural, anthropogenic factor has an influence in spatial grouping. Discriminant analysis (DA) was applied in order to identify discriminant groundwater quality parameters. DA reduced the number of data by extracting two parameters (iron and arsenic). The spatial distribution of identified dominant factors and discriminant parameters were graphically represented using GIS. Finally, the artificial neural network technique was used to test the ability to predict spatial changes in the values of discriminant parameters, and the reliability of this technique to predict the spatial variations of the two extracted variables has been proven.
The catalytic activity of the walnut shell ash was investigated in the biodiesel production by the sunflower oil methanolysis. The catalyst was characterized by the TG-DTA, XRD, Hg porosimetry, N2 ...physisorption, SEM, and Hammett method. In addition, the effects of the catalyst loading and the methanol-to-oil molar ratio on the methyl esters synthesis were tested at the reaction temperature of 60 °C. The walnut shell ash provided a very fast reaction and a high FAME content (over 98%). As the reaction occurred in the absence of triacylglycerols mass transfer limitation, the pseudo-first-order model was employed for describing the kinetics of the reaction. The catalyst was successfully reused four times after the regeneration of the catalytic activity by recalcination at 800 °C.
•The walnut shell ash is used as novel, inexpensive and efficient catalyst.•The sunflower oil methanolysis catalyzed by walnut shell ash is a very fast reaction.•The kinetics of the reaction was described by the pseudo-first-order model.•The regeneration of the catalytic activity by recalcination.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
This study explores differences between more and less competent peers in joint problem solving dialogues, related to opposite interaction outcomes of more competent students (progression/regression). ...Ten asymmetrical peer dyads were selected from 47 dyads participating in the previous study: five in which more competent (MC) student progressed the most, and five in which MC students regressed the most after a post-test. Ten dialogue characteristics were established in 50 conversations of these dyads. Cluster analysis revealed two dialogue types associated with different interaction outcomes of MC students. In the first one, MC students justified correct answers but behaved inconsistently with their higher competences. The second cluster characterizes domination-submissiveness pattern and MC students’ unwillingness to justify opinion. All regressing MC students participated in the first dialogue type and 56% of progressing MC students in the second. Qualitative analysis of the conversations typical for extracted clusters implies that although ready to provide arguments to their peers when they can, regressing MC students exhibit uncertainty, thereby losing from interaction. Progressing MC students seem to protect themselves against possible interaction disturbances by dominant attitude and withdrawal from communication.
In this study, estimation capacities and optimization of a dye concentration sensing model by an adapted neuro-fuzzy inference system (ANFIS) as well as central composite design coupled with response ...surface methodology using a plastic optical fiber (POF) based sensor were investigated. Various diameters
of POF were used for sensing different concentrations of Remazol Black B (RBB), which acts as a sensing medium of the process. The efficiency of sensing was studied as a function of three independent variables: diameter of POF, concentration of RBB dye, and initial temperature of the solution. First, the independent parameters were fed as inputs to an ANFIS, and the output of the system was the output intensity of dye ratio to output the intensity of distilled water. ANFIS showed that this established model is reliable for a dye concentration sensing process and is mainly influenced by its diameter.
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