Journal of Engineering & Processing Management (EPM)
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Sinteza, karakterizacija i ispitivanje antioksidativne aktivnosti estarskih i amidnih derivata 2,6-dimetil-4-supstituisane-1,4-dihidropiridin-3,5-dikarboksilne kiseline
Full text linkSix ester and amide derivates of 2,6-dimethyl-4-(substituted)-1,4-dihydropyridine-3,5-dicarboxylic acid have been synthesized in this paper, including: diethyl 2,6-dimethyl-4-phenyl-1,4-dihydropyridine-3,5-dicarboxylate, diethyl 2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate, diethyl 2,6-dimethyl-4-(4-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate, diethyl 4-(2-hydroxyphenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate, diethyl 4-(3-hydroxyphenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate and diethyl 4-(4-hydroxyphenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate. Obtained ester derivates were used afterwards as a starting compounds for synthesis of amide derivates, including: 2,6-dimethyl-4-phenyl-N3,N5-di(thiazol-2-yl)-1,4-dihydropyridine-3,5-dicarboxamide, 2,6-dimethyl-4-(3-nitrophenyl)-N3,N5-di(thiazol-2-yl)-1,4-dihydropyridine-3,5-dicarboxamide, 2,6-dimethyl-4-(4-nitrophenyl)-N3,N5-di(thiazol-2-yl)-1,4-dihydropyridine-3,5-dicarboxamide, 4-(2-hydroxyphenyl)-2,6-dimethyl-N3,N5-di(thiazol-2-yl)-1,4-dihydropyridine-3,5-dicarboxamide, 4-(3-hydroxyphenyl)-2,6-dimethyl-N3,N5-di(thiazol-2-yl)-1,4-dihydropyridine-3,5-dicarboxamide and 4-(4-hydroxyphenyl)-2,6-dimethyl-N3,N5-di(thiazol-2-yl)-1,4-dihydropyridine-3,5-dicarboxamide. Obtained compounds were characterized by melting point, elementary analysis and FT-IR spectroscopy. In order to determine the effect of the substituent, the antioxidative activity assay of obtained 1,4-dihydropyridines was performed by using the DPPH (1,1-diphenyl-2-picryl-hydrazyl) free radical scavenging method
Review of electrospray observations and theory
Full text linkWhile a liquid is dripping out of a capillary tube, there is a possibility to affect the characteristics of the exiting flow in certain ways. One of the ways already used is by introducing an electric field that can be used to change the average droplet diameter and the droplet size distribution. This process is called electrospraying, while the theory behind it is sometimes called electrohydrodynamics (EHD). This phenomenon has been investigated for more than a hundred years both empirically and theoretically. In this paper, a review of the available literature and the empirical and theoretical findings is presented. A new classification of the electrospray modes had to be given to include all the different modes mentioned by different authors. The necessary pieces of the equipment and their different types are also given
Recovery of yttrium oxide from titanium-aluminium based wastes
No full textYttrium belongs to the rare earth elements and critical metals. Yttrium oxide is mostly used in fluoroscent lamps, production of electrodes, in electronic filters, lasers, superconductors and as additives in various titanium-aluminium materials to improve their properties. Recovery of yttrium oxide from secondary sources such as red mud, coatings from ceramic industry and phosphors is extremely important. The main aim of this study is to examine the selective recovery of yttrium oxide from Al-Ti based secondary materials using one combined method based mostly on leaching for selective recovery of yttrium containing: crashing and grinding of materials, sieving, leaching of chosen fine fraction with hydrochloric acid, precipitation with oxalic acid in order to produce a pure yttrium oxalate, filtration and a final thermal decomposition of yttrium oxalate. The present study summarized mostly the influence of different reaction parameters such as leaching temperature, time and concentration of hydrochloric acid on yttrium dissolution from Al-Ti based secondary materials. An increase of dissolution time and temperature increases yttrium dissolution. An increase of pressure from an atmospheric pressure to 0.5 MPa at 150 °C leads to the maximum dissolution of yttrium (about 98.6 %). The final produced yttrium oxide after thermal decomposition of yttrium oxalate was analyzed using SEM and EDS-analysis
Perceptions of nanotechnology utilization in food: a pilot study
Full text linkNanotechnology is a science field that includes research and applications carried out in the sphere of below 100 nanometers. Nanofood is the result of the usage of nanotechnology in food production, processing, and packaging. The paper presents results of a pilot study on perceptions of nanotechnology and its use in food production. A questionnaire was developed for the purpose of the study that measured knowledge, perceptions and attitudes towards nanotechnology and nanoproducts in general and in food industry. The results of the analysis suggested lack of knowledge about nanotechnology and its utilisation in food production. Motivation of respondents to purchase nanoproducts is low, mostly due to perceptions of possible changes in food caused by the use of nanotechnology. The respondents are aware of their poor understanding of nanotechnology and perceive potential risks related to the utilisation of nanotechnology. Education of consumers in relation to nanotechnology and its utilisation in manucaturing, especially in food production, is a necessary step in future development of this field
Application of validated mathematical model of composting process for study the effect of air flow rate on process performance
Full text linkThe objectives of this study were to develop and validate the mathematical model (kinetic and reactor model) of composting process, as well to used validated model in order investigate the effects of the air flow rate on organic matter conversion, carbon dioxide concentration and mixture temperature. The mathematical model incorporated two microbial populations that metabolized composting material which was split into two different fractions according to its degradability (easily-degradable and hardly-degradable). Comparisons of simulation and experimental results for five dynamic state variables demonstrated that the model has very good predictions of the composting process. Simulations with validated model showed that among three dynamic state variables (organic matter conversion, carbon dioxide concentration, mixture temperature), carbon dioxide concentration is the most sensitive while organic matter conversion is the least sensitive to the change of air flow rate
Imobilisation of alkali treated apricot shells as a biosorbent for heavy metals removal
No full textIn this work, the design and usage of biosorbents made of apricot shells (Prunus armeniaca L.), Na-alginate and bentonite, for heavy metals removal from wastewaters, were investigated. The effect of particle size on the biosorption process, were investigate and the smallest fraction, was immobilized in Na-alginate. Immobilization had a positive effect on the biosorption process, but due to the inhomogeneity of the granules, bentonite was added as a binding agent. The result was increase of Cu(II) and Zn(II) removal up to 35% and Pb(II) up to 60. The composed granules were used for real effluent treatment. Obtained results indicated that this kind of composite biosorbent can be used in treatment of effluents contaminated with heavy metals pollution
HACCP plan as a part of the food safety management system in the production of fermented milk products
No full textIn this paper the authors have developed and implemented a HACCP plan for the production process of fermented milk products, as exemplified in the yogurt sample. Hazard analysis included 241 hazard, of which 99 hazard can be eliminated and prevented their occurrence, by taking timely preventive measures. The HACCP system is necessary to apply for the removal of all 11 identified hazards. In the present model, the five CCP were identified, three of them for biological and one chemical and one physical hazards. During many years of practical application, developed HACCP system has demonstrated some application advantages in relation to other systems for ensuring food safety, such as: efficiency, simplicity and low cost applications
Estimation of antioxidative potential of thyme (Thymus alpestris L.)
Full text linkFamily Lamiaceae (labia) includes a large number of cosmopolitan species including Thymus alpestris (Thyme) characterized by the presence of essential oils and phenolic compounds. It represents a perennial semi-shrubby plant. The antioxidant potential of thyme is due to the presence of polyphenolic acids and flavonoids. The topic of this paper is the extraction of thyme (Thymus alpestris) with 40% ethanol and 50% ethanol, using Soxhlet method (circulatory extraction), after which, the content of phenolics and flavonoids was determined in order to confirm the antioxidant potential of this plant species. The results show that 40% ethanol extract has the highest content of phenolics and flavonoids and the highest antioxidant potential, resultingly
Determination of some physical-chemical properties of biofortification soft wheat and flour of the varieties “Treska”
Full text linkCereal crops as a basic food for humans, little is used as a grain, but with milling they are processed in the milling products: flour, meal, flakes and bran. Determining the content of some ingredients, such as protein, ash, wet gluten, fat, etc. in food products is important because they are present in the raw materials and final products. The importance of knowing the physical and chemical properties of wheat and flour is due to the determination of quality and kind of flour which is produced after milling process. The aim of this research is to examine the influence of Fe-EDTA fertilizers through soil, foliar and soil +foliar application on some physical and chemical properties of bio-fortification soft wheat and flour of the varieties ,,Treska ,, During the investigation we determined the highest ash content in the seed obtained with soil + foliar application of iron, while in the flour was measured the highest ash content by soil application of iron. We concluded that the supplement iron in soil increase the percentage of protein in the grain and flour. We found that soil + foliar application of iron leads to a significant increase of % fat and wet gluten in grain and flour compared to soil or foliar application of chelating fertilizers. It might be concluded that the agronomic bio-fortification with Fe-EDTA soil + foliar application and Fe-EDTA soil leads to improved examined physical - chemical properties of wheat and flour
Composting kinetics for mixture of poultry manure and wheat straw based on volatile solids content
Full text linkThe aim of this study was to determine the composting kinetics for mixture of poultry manure and wheat straw based on the volatile solids content. Experimental data was fitted with the first-order and the nth-order kinetic model. The nth-order kinetic model showed better prediction performance than the firstorder kinetic model. For the first-order kinetic model, maximum and mean differences between experimental and simulation results for the content of volatile solids were 5.43% and 3.00%, for the first reactor, and 4.68% and 2.12% for the second reactor, respectively, for the nth-order kinetic model, maximum and mean differences were 4.92% and 1.68%, for the first reactor, and 4.09% and 1.42% for the second reactor, respectively