Low-calorie marmalades

The number of people suffering from insulin-dependent (Diabetes Melitus type I) and insulin-independent (Diabetes Melitus type II) is huge, and the number of potential diseased is in permanent rise. For that reason products with reduced amount of sugar have become very popular. Factory "Srbijanka" Valjevo manufactures reduced–sugar marmalades from apricot peach, strawberry, apple and orange. Low–metoxyl pectins and high-grade locust bean gum were used as gelation agents. Sensory evaluation and energy value of these marmalades were determined and all samples were highly graded. All marmalades belonged to the group of low-calorie (dietetic) products

Istraživanje optimalnih parametara solarnih paraboličnih koncentrišućih prijemnika toplote sa aspekta primene u sistemima poligeneracije

The work within the PhD thesis includes research and development of energy and environmental highly effective concentrating solar systems and receivers. The solar parabolic concentrator consists of a multi-segmented parabolic reflector and spiral corrugated heat absorber. Examinations of solar parabolic concentrating collectors are focused on the analysis of different concepts of solar optical concentrator, different concepts of solar receivers (absorbers), and the optimizing geometrical and optical parameters for different levels of generated power (up to 10 kW). The aim of developing this type of solar concentrator is to increase the coefficient of the concentration ratio, increase the efficiency of utilization of solar energy, increase the efficiency of converting solar energy into other forms of energy, and reduce the prices of the obtained heat, cooling or electricity. The development of the solar parabolic concentrator is based on a long-term review of the literature and analysis of a large number of different solutions. The subject of this PhD thesis is the development, design and construction of the prototype solar parabolic concentrating collector (concentrator of solar radiation plus receiver) from the aspect of the polygeneration systems. The main objective of creating this doctoral thesis is that by using modern experimental and numerical research methods perform theoretical and experimental research of solar parabolic concentrating heat collectors, and came to the optimal solution for our the conditions. Based on the obtained optimal solution was developed 3D model parabolic concentrators and numerical analysis was conducted from the standpoint of optical design concentrator solar, thermal behavior of concentrated solar radiant heat absorber, non-linear FEM analysis of the stability of the system to the impact of its own weight and wind loads. Based on the geometric and optical optimization made the final numerical model and the physical prototype of real solar parabolic concentrator that is tested in real conditions. On the basis of the experiment was performed and verification of mathematical models of the solar parabolic concentrator

Istraživanje optimalnih parametara solarnih paraboličnih koncentrišućih prijemnika toplote sa aspekta primene u sistemima poligeneracije

The work within the PhD thesis includes research and development of energy and environmental highly effective concentrating solar systems and receivers. The solar parabolic concentrator consists of a multi-segmented parabolic reflector and spiral corrugated heat absorber. Examinations of solar parabolic concentrating collectors are focused on the analysis of different concepts of solar optical concentrator, different concepts of solar receivers (absorbers), and the optimizing geometrical and optical parameters for different levels of generated power (up to 10 kW). The aim of developing this type of solar concentrator is to increase the coefficient of the concentration ratio, increase the efficiency of utilization of solar energy, increase the efficiency of converting solar energy into other forms of energy, and reduce the prices of the obtained heat, cooling or electricity. The development of the solar parabolic concentrator is based on a long-term review of the literature and analysis of a large number of different solutions. The subject of this PhD thesis is the development, design and construction of the prototype solar parabolic concentrating collector (concentrator of solar radiation plus receiver) from the aspect of the polygeneration systems. The main objective of creating this doctoral thesis is that by using modern experimental and numerical research methods perform theoretical and experimental research of solar parabolic concentrating heat collectors, and came to the optimal solution for our the conditions. Based on the obtained optimal solution was developed 3D model parabolic concentrators and numerical analysis was conducted from the standpoint of optical design concentrator solar, thermal behavior of concentrated solar radiant heat absorber, non-linear FEM analysis of the stability of the system to the impact of its own weight and wind loads. Based on the geometric and optical optimization made the final numerical model and the physical prototype of real solar parabolic concentrator that is tested in real conditions. On the basis of the experiment was performed and verification of mathematical models of the solar parabolic concentrator

Istraživanje optimalnih parametara solarnih paraboličnih koncentrišućih prijemnika toplote sa aspekta primene u sistemima poligeneracije

The work within the PhD thesis includes research and development of energy and environmental highly effective concentrating solar systems and receivers. The solar parabolic concentrator consists of a multi-segmented parabolic reflector and spiral corrugated heat absorber. Examinations of solar parabolic concentrating collectors are focused on the analysis of different concepts of solar optical concentrator, different concepts of solar receivers (absorbers), and the optimizing geometrical and optical parameters for different levels of generated power (up to 10 kW). The aim of developing this type of solar concentrator is to increase the coefficient of the concentration ratio, increase the efficiency of utilization of solar energy, increase the efficiency of converting solar energy into other forms of energy, and reduce the prices of the obtained heat, cooling or electricity. The development of the solar parabolic concentrator is based on a long-term review of the literature and analysis of a large number of different solutions. The subject of this PhD thesis is the development, design and construction of the prototype solar parabolic concentrating collector (concentrator of solar radiation plus receiver) from the aspect of the polygeneration systems. The main objective of creating this doctoral thesis is that by using modern experimental and numerical research methods perform theoretical and experimental research of solar parabolic concentrating heat collectors, and came to the optimal solution for our the conditions. Based on the obtained optimal solution was developed 3D model parabolic concentrators and numerical analysis was conducted from the standpoint of optical design concentrator solar, thermal behavior of concentrated solar radiant heat absorber, non-linear FEM analysis of the stability of the system to the impact of its own weight and wind loads. Based on the geometric and optical optimization made the final numerical model and the physical prototype of real solar parabolic concentrator that is tested in real conditions. On the basis of the experiment was performed and verification of mathematical models of the solar parabolic concentrator

Optical modeling of a solar dish thermal concentrator based on square flat facets

Solar energy may be practically utilized directly through transformation into heat, electrical or chemical energy. We present a procedure to design a square facet concentrator for laboratory-scale research on medium-temperature thermal processes. The efficient conversion of solar radiation into heat at these temperature levels requires the use of concentrating solar collectors. Large concentrating dishes generally have a reflecting surface made up of a number of individual mirror panels (facets). Optical ray tracing is used to generate a system performance model. A square facet parabolic solar concentrator with realistic specularly surface and facet positioning accuracy will deliver up to 13.604 kW of radiative power over a 250 mm radius disk (receiver diameter) located in the focal plane on the focal length of 1500mmwith average concentrating ratio exceeding 1200. The Monte Carlo ray tracing method is used for analysis of the optical performance of the concentrator and to identify the set of geometric concentrator parameters that allow for flux characteristics suitable for medium and high-temperature applications. [Projekat Ministarstva nauke Republike Srbije, br. III42006: Research and development of energy and environmentally highly effective polygeneration systems based on renewable energy resources

Patogena mikobiota žute lincure (Gentiana lutea L.)

Mycopopulation of yellow gentian growing in plantations was studied in 2008 and 2009. Fourteen species of fungi were registered at seed, out of which five were pathogenic. The most common species was Alternaria alternata (72-74 %). Species of the genus Fusarium (F. oxysporum, F. solani and F. equiseti) were present in a small percentage (2-6 %). These species, as well as F. verticillioides, were isolated from root, and Fusarium sp. was isolated from the flowers. Alternaria alternate, Epicoccum purpurescens, Phoma sp. and Alternaria sp. were regularly present on the leaves and stems.Žuta lincura je višegodišnja zeljasta biljka planinskih livada i pašnjaka na nadmorskim visinama između 800 i 2500 metara. Raste i u retkim šumama i na kamenjarima. Kao sirovina za farmaceutsku industriju koristi se prvenstveno koren, a u novije vreme list i cvet. Da bi se sačuvao biodiverzitet i povećao prinos ujednačenog kvaliteta, lincura se sve više plantažno gaji u svetu, a kod nas poslednjih šest godina. Plantažnim gajenjem žute lincure stvoreni su uslovi za pojavu većeg broja patogenih gljiva u različitim fenofazama razvića. Proučavanje patogene mikoflore žute lincure ispitivano je na plantaži Instituta za proučavanje lekovitog bilja, Beograd, u nacionalnom parku 'Tara' tokom 2008. i 2009. godine. Preko 70% semena žute lincure bilo je napadnuto vrstom Alternaria alternata. U većini slučajeva, seme zaraženo ovom gljivom uopšte ne klija. Vrste iz roda Fusarium (F. oxysporum, F. solani i F. equisti), zastupljene su u manjem procentu (2-6%) i prouzrokuju u prvom redu smanjenje energije klijanja i klijavosti semena, a zatim i truljenje i propadanje klijanaca. Na korenu je konstatovano prisustvo mešane infekcije sa Fusarium oxysporum, F. solani i F. verticillioides. Sa nadzemnih delova lincure izolovane su Alternaria spp., Alternaria alternata, Epicoccum purpurescens, Phoma ps. i Fusarium sp

Design, simulation and optimization of a solar dish collector with spiral-coil thermal absorber

The efficient conversion of solar radiation into heat at high temperature levels requires the use of concentrating solar collectors. The goal of this paper is to present the optical and the thermal analysis of a parabolic dish concentrator with a spiral coil receiver. The parabolic dish reflector consists of 11 curvilinear trapezoidal reflective petals constructed by PMMA with silvered mirror layer and has a diameter of 3.8 m, while its focal distance is 2.26m. This collector is designed with commercial software SolidWorks and simulated, optically and thermally in its Flow Simulation Studio. The optical analysis proved that the ideal position of the absorber is at 2.1m from the reflector in order to maximize the optical efficiency and to create a relative uniform heat flux over the absorber. In thermal part of the analysis, the energetic efficiency was calculated approximately 65%, while the exergetic efficiency is varied from 4% to 15% according to the water inlet temperature. Moreover, other important parameters as the heat flux and temperature distribution over the absorber are presented. The pressure drop of the absorber coil is calculated at 0.07bar, an acceptable value

Thermal and exergetic investigation of a solar dish collector operating with mono and hybrid nanofluids

The use of solar dish thermal collectors is a promising choice for designing sustainable energy systems. The use of nanofluids is a new way for enhancing the thermal performance of solar collectors because of their improved thermal properties. The objective of this study is to investigate the use of mono and hybrid nanofluids in a solar dish collector in order to determine which kind of nanofluids leads to higher performance enhancements. The analysis is conducted with a developed thermal model in Engineering Equation Solver and the collector is studied thermally and exergetically. The examined hybrid nanofluid has as base fluid syltherm 800 with 1% Cu and 1% TiO2. Moreover, the examined mono nanofluids are the syltherm 800 with 2% Cu and syltherm 800 with 2% TiO2. The investigated solar dish collector has a spiral absorber and it is examined for inlet temperatures from 25°C up to 300°C with a flow rate of 200 L/h. According to the final results, the use of hybrid nanofluid leads to higher thermal efficiency enhancement compared to the mono nanofluids because of the higher increase in the Nusselt number in the flow. More specifically, the use of the hybrid nanofluids leads to 0.99% mean thermal efficiency enhancement compared to the pure oil case, while the use of Oil/Cu and Oil/TiO2 lead to 0.42% and to 0.56% mean thermal efficiency enhancement, respectively. Moreover, the exergy efficiency is found enhanced with the use of all nanofluids. The mean exergy efficiency enhancement is 1.21% with the hybrid nanofluid, while it is 0.73% with Oil/TiO2 and 0.53% with Oil/Cu. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III42006: Research and development of energy and environmentally highly effective polygeneration systems based on renewable energy resources

Application of gas chromatography analysis to quality control of residual organic solvents in clopidogrel bisulphate

A direct-injection, split-mode capillary gas chromatographic procedure with a flame ionization detection is developed for the analysis of eight solvents used in the synthesis and purification of an anti-thrombotic drug clopidogrel bisulphate. The solvents analyzed were methanol, acetone, dichloromethane (DCM), 2-butanol, cyclohexane, toluene, acetic acid and N, N-dimethyl formamide (DMF). In addition, as a result of dehydration of 2-butanol during drying process, in clopidogrel bisulphate samples, significant amounts of 2-butanol dehydration products (1-butene, cis and trans isomers of 2-butene, 2,2'-oxydibutane and 1-(1-methylpropoxy)butane) may be detected. The content of each of these volatile products can be evaluated using the same gas-chromatographic method, with quantification based on the response factor established for the chromatographic peak of 2-butanol. For each solvent used in the process of clopidogrel bisulphate preparation, the procedure is validated for selectivity, linearity, recovery, precision, robustness, quantitation limit, and detection limit. All eight solvents plus five 2-butanol degradation products are fully separated. System suitability test is validated, and requirements are set. Based on a large number of result sets, retrospectively, from many different batches analyzed, conclusions were made about process variations and reliability and a lack of consistency was identified in the quality of the active substance from a particular producer source. Multivariate analysis was used as statistical technique to classify samples. From the analyzed set of 11 solvents, 6 of them were preselected based upon their occurrence in the samples and both Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) were performed

Application of gas chromatography analysis to quality control of residual organic solvents in clopidogrel bisulfate

A direct-injection, split-mode capillary gas chromatographic procedure with flame ionization detection was developed for the analysis of eight solvents used in the synthesis and purification of the anti-thrombotic drug clopidogrel bisulfate. The solvents analyzed were methanol, acetone, dichloromethane (DCM), 2-butanol, cyclohexane, toluene, acetic acid and N, N-dimethylformamide (DMF). In addition, because of dehydration of 2-butanol during the drying process, significant amounts of 2-butanol dehydration products (1-butene, cis- and trans-isomers of 2-butene, 2,2-oxybis[butane] and 1-(1- -methylpropoxy)butane) may be detected in clopidogrel bisulfate samples. The content of each of these volatile products can be evaluated using the same gaschromatographic method, with quantification based on the response factor established for the chromatographic peak of 2-butanol. Based on a large number of result sets, retrospectively, from many different batches analyzed, conclusions were made about process variations and reliability and a lack of consistency was identified in the quality of the active substance from a particular producer source. Multivariate analysis was used as the statistical technique to classify the samples. From the analyzed set of 11 solvents, 6 of them were preselected based upon their occurrence in the samples and both Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) were performed