Entity

Time filter

Source Type


Milic P.,High Chemical and Technological School for Professional Studies
Srpski Arhiv za Celokupno Lekarstvo | Year: 2011

This paper explains the social and healthcare related conditions in the Leskovac region during 18th and 19th century, and the foundation of the first pharmacy in Serbia. Based on the available historical facts and private documents, the history of the origin and activities of the first pharmacy in the Leskovac region during the Turkish reign in 1862 is presented. The paper also mentions the founder, Dr. Alexiadis (Greek by origin), who was a doctor working in pharmaceutical industry, as well as his son Mgr.Ph. Djordje Aleksić, born in 1847 in Ioannina (Greece) and graduated from the Pharamacy Faculty in Constantinople in 1875, who later became the owner. After graduation, Mgr.Ph. Djordje Aleksić came in Leskovac and took over the "Hipokrat" pharmacy from his father, and started pharmacy business in Leskovac in the true meaning of that word.


Milic P.S.,High Chemical and Technological School for Professional Studies | Bekric D.M.,D.O.O. Alfa Laboratory | Rajkovic K.M.,High Chemical and Technological School for Professional Studies
Hemijska Industrija | Year: 2011

The present work deals with the mineral composition of the extracts obtained from lady's bedstraw (Galium mollugo L.) by maceration, extraction under reflux (extraction at the boiling temperature of solvent) and ultrasonic extraction, using atomic absorption spectrometry. The main goals of the work were to evaluate the operation of an artificial neural network (ANN) of the selected topology, to determine the parameters of a kinetic model of unsteady diffusion of minerals through plant material, and to define the yield of minerals as a function of the time of extraction and the yield of total extract (resinoid). The ANN results showed a positive correlation with the experimental data, so they could be used to examine the kinetics of extraction of minerals from lady's bedstraw (G. mollugo), regardless of the extraction technique. The yield of minerals (K, Ca and Mg) was correlated with the time of extraction and the yield resinoid by a polynomial equation of the first order in both variables.


Stamenkovic O.S.,University of Nis | Velickovic A.V.,University of Nis | Kostic M.D.,University of Nis | Jokovic N.M.,University of Nis | And 2 more authors.
Energy Conversion and Management | Year: 2015

Abstract The methanolysis of hempseed oil catalyzed by potassium hydroxide was studied using the full central composite rotatable design. The methanolysis reaction was modeled and optimized by the response surface methodology (RSM) and an artificial neural network model combined with a genetic algorithm (ANN-GA). All individual factors have significant influence on the FAME content (p-value < 0.05). Based on the coefficient of determination and the mean relative percentage deviation (0.996 and ±0.2% for RSM and 0.870 and ±2.9% for ANN, respectively), the RSM model demonstrated a better data modeling and more efficient prediction capability than the ANN-GA model. Also, the former predicted the more favorable optimum reaction temperature and methanol:hempseed oil molar ratio (43.4°C and 6.4:1) than the latter (56.8°C and 8.5:1) at a somewhat higher catalyst loading (1.2% versus 1.0%). Moreover, the RSM model predicted the maximum FAME content of 99.8% (actual content: 98.5%) in 30 min, while the ANN-GA model resulted in the best predicted yield of 97.1% (actual content: 97.5%) within 12 min. Generally, the properties of obtained FAME are within the specifications of the biodiesel standards. © 2015 Elsevier Ltd.


Kostic M.D.,University of Nis | Jokovic N.M.,University of Nis | Stamenkovic O.S.,University of Nis | Rajkovic K.M.,High Chemical and Technological School for Professional Studies | Veljkovic V.B.,University of Nis
Industrial Crops and Products | Year: 2013

The influence of extraction temperature, solvent:seed ratio and extraction time on hempseed oil yield was investigated. The oil extraction was optimized using the response surface methodology (RSM) coupled with a 33 full factorial experiment with two replications and an artificial neural network (ANN) model. For the former method, the second-order polynomial equation and the analysis of variance were used for evaluating the significance of the influence of the extraction variables on hempseed oil yield and for optimizing the extraction process. The ANN model was combined with a genetic algorithm (GA) for the process optimization. The low mean relative percent deviation (MRPD) between the experimental data and predicted oil yield obtained by using RSM and ANN models showed that both models were suitable for modeling the extraction process. The ANN model was more accurate because of lower MRPD value (±1.0%) than the second-order polynomial equation (±2.3%). The established optimal extraction conditions for achieving the maximum hempseed oil yield based on the ANN-GA methodology were extraction temperature 70°C, solvent:seed ratio of 10:1 and 10min extraction time, under which the predicted and actual hempseed oil yields were 29.56g/100g and 29.06±0.11g/100g, respectively. Unsaturated linoleic, linolenic and oleic fatty acids were the main fractions of the fatty acids in the hempseed oil, although the saturated fatty acids were also present. © 2013 Elsevier B.V.


Kostic M.D.,University of Nis | Jokovic N.M.,University of Nis | Stamenkovic O.S.,University of Nis | Rajkovic K.M.,High Chemical and Technological School for Professional Studies | Veljkovic V.B.,University of Nis
Industrial Crops and Products | Year: 2014

The influence of extraction temperature and seed-to-solvent ratio in the ranges of 20-70. °C and 1:3-1:10. g/mL, respectively on the hempseed oil extraction by n-hexane was investigated in order to conduct both kinetic and thermodynamic analysis. For the kinetic modeling, it was assumed that washing and diffusion occurred simultaneously. A four-parameter phenomenological model fitted the experimental data with a mean relative percent deviation (MRPD) of ±2.5% (based on 125 data). The extraction conditions did not influence the fraction of washable hempseed oil (f= 0.821 ± 0.006), but affected the washing and diffusion rate constants. A modified Arrhenius equation was used to correlate the rate constants with extraction temperature and solvent-to-seed ratio. Since the washing rate constant was much higher than the diffusion rate constant, the kinetics of the hempseed oil extraction could be successfully described by a simpler three-parameter model based on the assumption of instantaneous washing followed by diffusion (MRPD= ±2.8%). The hempseed oil extraction was shown by a thermodynamical analysis to be feasible, spontaneous, endothermic and irreversible. Depending on the seed-to-solvent ratio, the hempseed oil yield increased by a factor of 1.012-1.027 for every 10. °C rise in temperature. © 2013 Elsevier B.V.

Discover hidden collaborations