A FUNCTION PROPERTY OF POLYTROPHIC PROCESS WITH ASPECT OF TANGENT CONSTRUCTION

In this paper, starting from general tangent equation in arbitrary point of specified curve, using principles of differential geometry and given mathematical transformation tangent equation of polytrophic function in p – v diagram was obtained. This form is convenient for solving numerous practical and theoretical problems in engineering thermodynamic by means of graphical method. It was shown that tangent can be constructed easily, using polytrophic equation only, but it is not example with other functions appearing in thermodynamics. Later, in this paper, we have given some methods, which refer to more exact construction of polytrophic and graphical analyze of polytrophic process

PRESSURE INFLUENCE TO EXTRACTION SYSTEM HELICHRYSUM ITALICUM – SUPERCRITICAL CARBON DIOXIDE

Supercritical fluid extraction (SFE) is an efficient extraction technique for the separation of various organic compounds from herbs, or more generally, from plant materials. As cultivate plant (plant from plantation) Helichrysum italicum from municipality Novi Grad was used in this research. The influence of pressure on total extract yield at flow rate 53.5 dm3 /h (calculated at normal state), for extraction time 3 h was investigated. Extraction was performed by supercritical carbon dioxide at different pressures (80, 150, 250 and 350 bar) and constant temperature of 40°C. The extraction yield increase from 0.35 to 5.71% (g/100g drug) by pressure increasing of supercritical extraction by carbon dioxide (isothermal process, t = 40°C). Essential oil content in obtained CO2 extracts was from 6.70 to 31.12%. The highest content of essential oil was in CO2 extract obtained by extraction of drug at p = 80 bar and t = 40°C (31.12%). Qualitative and quantitative determination of CO2 extracts obtained at pressure of 80 and 350 bar as well as of essential oils obtained from extracts, were performed using GC - MS method. The main component were tritriacontane (27.13%) and nonacosane (13.28%). The dominant component in essential oils obtained from extracts was γ – curcumene (28.27 and 27.42%, respectively)

CALCULATION OF RELIABILITY OF TYPICAL COOLING SYSTEM BY DESIGNING OF TREE FAILURE METHOD

In the introductory part we give definitions and relationships to determine the reliability and probability of failure of technical systems. After that, the analysis and calculation of reliability, we proposed method, based on the construction of tree failure in the form of logical structure. The second part was performed to verify the model set on an example of typical cooling system. During this side of event for the loss has taken the minimum required flow of cooling fluid in heat exchanger . On the basis of tree failure in the general analysis is determined by the probability of adverse events, and reliability. At the end of the paper, the estimation of probability of failure, made the estimate, based on weight of i - event, using a typical circuit

Elektrohemijsko generisanje katalizatora za Majklovu adiciju dikarbonilnih jedinjenja i cijanida na akriloilferocen

Michael addition of diethyl malonate, ethyl acetoacetate, acetylacetone, and cyanide anion to acryloylferrocene promoted by a catalyst in situ generated from a sacrificial zirconium anode is described. Most of the obtained compounds were identified by comparison of their spectral and physical data with those published elsewhere, whereas the only newly synthesized compound - diethyl 2,2-bis(3-ferrocenyl-3-oxopropyl)malonate - was completely characterized by spectral (IR, 1H- and 13C-NMR), physical and crystallographic (single-crystal X-ray) data.Opisana je Majklova adicija dietil-malonata, etil-acetoacetata, acetilacetona i cijanidnog anjona na akriloilferocen pomoću katalizatora generisanog in situ sa rastvorne anode od cirkonijuma. Većina dobijenih jedinjenja je identifikovana poređenjem njihovih fizičkih i spektroskopskih podataka sa literaturnim, a jedino novo jedinjenje je potpuno opisano spektroskopskim (IR, 1H- i 13C-NMR) i fizičkim podacima, kao i podacima iz kristalografske analize X-zracima

HEAT TRANSFER THROUGH FLAT WALLS COMPLEX PROMBLEMS SOLVING BY ELECTRICAL ANALOGY

Starting from the Fourier's law for stationary heat transfer and Ohm's law for DC through the resistor, the paper presents the analogy between thermodynamic and electrical quantities. Based on this analogy, has been used knowledge of circuit theory for of the heat transfer through walls in the multilayer characteristic positions to derive the schematic representation of corresponding heat resistors. At the end of paper, has been shown two typical examples of calculation heat transfer to the complex multi-layer walls in different positions, by applied electrical analogy.Heat transfer, Electrical analogy, Heat resistance, Electrical resistance, Equivalent system

Analiza stabilnosti brane „Lipovica“ primenom Karlsrue metode

U radu je prikazana analiza stabilnosti geodetske 2D mreže brane „Lipovica“ primenom Karlsrue metode deformacione analize. U prvom delu rada, data je uopštena klasifikacija deformacionih modela koji se koriste prilikom realizacije geodetskog osmatranja. Posebno poglavlje posvećeno je opisu same Karlsrue metode, njenom algoritmu kao i načinu primene. Efikasnost metode je zasebno razmatrana na praktičnom primeru geodetske 2D mreže brane „Lipovica“ čiji su podaci kontrolne ephe simulirani. Ovom analizom utvrđena je saglasnost između simuliranih vrednosti pomeranja sa vrednostima koje su otkrivene Karlsrue metodom, pri čemu su u radu dostupni svi ulazni podaci neophodni za ponavljanje postupka

PRESSURE INFLUENCE TO EXTRACTION SYSTEM HELICHRYSUM ITALICUM – SUPERCRITICAL CARBON DIOXIDE

Supercritical fluid extraction (SFE) is an efficient extraction technique for the separation of various organic compounds from herbs, or more generally, from plant materials. As cultivate plant (plant from plantation) Helichrysum italicum from municipality Novi Grad was used in this research. The influence of pressure on total extract yield at flow rate 53.5 dm3 /h (calculated at normal state), for extraction time 3 h was investigated. Extraction was performed by supercritical carbon dioxide at different pressures (80, 150, 250 and 350 bar) and constant temperature of 40°C. The extraction yield increase from 0.35 to 5.71% (g/100g drug) by pressure increasing of supercritical extraction by carbon dioxide (isothermal process, t = 40°C). Essential oil content in obtained CO2 extracts was from 6.70 to 31.12%. The highest content of essential oil was in CO2 extract obtained by extraction of drug at p = 80 bar and t = 40°C (31.12%). Qualitative and quantitative determination of CO2 extracts obtained at pressure of 80 and 350 bar as well as of essential oils obtained from extracts, were performed using GC - MS method. The main component were tritriacontane (27.13%) and nonacosane (13.28%). The dominant component in essential oils obtained from extracts was γ – curcumene (28.27 and 27.42%, respectively)

A FUNCTION PROPERTY OF POLYTROPHIC PROCESS WITH ASPECT OF TANGENT CONSTRUCTION

In this paper, starting from general tangent equation in arbitrary point of specified curve, using principles of differential geometry and given mathematical transformation tangent equation of polytrophic function in p – v diagram was obtained. This form is convenient for solving numerous practical and theoretical problems in engineering thermodynamic by means of graphical method. It was shown that tangent can be constructed easily, using polytrophic equation only, but it is not example with other functions appearing in thermodynamics. Later, in this paper, we have given some methods, which refer to more exact construction of polytrophic and graphical analyze of polytrophic process