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)

THE DEVELOPMENT OF MODERN LOW TEMPERATURE FUEL CELLS

Classification of fuel cells is presented. Progress in low temperature fuel cells fueled by hydrogen, methanol and formic acid is discussed and the possible future use of fuel cells is indicated. Ethanol is a special fuel because it is available from renewable environmentally friendly sources and its oxidation product (CO2) can be transformed by photosynthesis to ethanol. The design of the anode catalyst for electrochemical ethanol oxidation in the Direct Ethanol Fuel Cell (DEFC) is described in some detail

A CURRICULUM ANALYSIS AND INTEGRATION OF CHEMICAL ENGINEERING EDUCATION

Most commonly, all reforms of curriculum and study programmes in the educational system of Chemical Engineering are based on knowledge integration and developing tools which are designed to help students acquire a global picture of their professional calling. Therefore, this reform, which is the most comprehensive so far, and which was caused by the implementation of the Bologna model as well as by the small number of students at technical faculties, has a major significance for all the faculties of Chemical Engineering. This study, apart from presenting the factors which affect the development of studies in this area, gives a thorough review of the past and the existing educational systems at the faculties of Chemical Engineering in Europe. Thus the implementation of the Bologna model is used in order to harmonize curricula in the educational system of Chemical Engineering in Europe through defined goals of knowledge acquisition and a basic curriculum with the topics that should be incorporated in the curriculums of all the faculties of Chemical Engineering

Influence of pressure and time on extraction process using supercritical CO2

The supercritical fluid extraction (SFE) by carbon dioxide (CO2) of Salvia officinalis L. was investigated. SFE by CO2 was performed at different pressure (80, 100, 150, 200 and 300 bar) and constant temperature of 40ºC (all other extraction conditions, such are flow rate, particle diameter of Salvia officinalis, extraction time were kept constant. The GC-MS method was used for determination of qualitative and quantitative composition of obtained extracts and essential oils

Induction and synchronization of estrus in dairy cows using a single injection of PGF2α and GnRH

The aim of this study was to examine the effects of treatment with a single injection of GnRH and PGF2α on estrous response, fertility and service period. A total of 120 lactating Simmental cows were divided into four groups of 30 cows each: group PGF2α 40 was treated on the 40th day post partum with a single injection of 2 mL prostaglandin analogue (Estrumate), group PGF2α 50 was treated in the same way on the 50th day, group GnRH was treated on the 40th day post partum with a single injection of 2 mL GnRH analogue (Receptal), and the fourth group (control) was not hormonally treated. Fertility of cows was not significantly different (p>0.05). The difference in the estrous response and service-period between the control group and experimental groups was statistically significant (p<0.01)

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)

INFLUENCE OF PARTICLE SIZE TO EXTRACTION KINETICS OF SAGE BY SUPERCRITICAL CARBON DIOXIDE

Sage with different degrees of fragmentation was extracted at the plant for extraction of gases under pressure (HPEP, Nova Swiss, Switzerland). Plant material - drug consisted of dried leaves of sage (Salviae folium), collected from harvested wild plants after flowering (Salvia officinalis L.) in the region of Trebinje during 2007. year. The initial content of extracted substances (q0 = 3.70 g/100g drug) in leaves of sage (Salviae folium) was determined and the kinetics of extraction was tested by determining the content of residual substances in drug (qi, g/100g drug) during the extraction time. From these results the rapid extraction coefficient, b*, slow extraction coefficient, k, and coefficient of internal diffusion, Du, were determined for the assumed forms (plate, cylinder). It is shown that with increasing fragmentation of drugs fast extraction coefficient, b* (0.02 to 0.20) and slow extraction coefficient, k (0.292 to 0.480 h-1 ) are increasing. The value of the coefficient of internal diffusion, Du was decreasing with increasing degree of fragmentation of drugs with 6.11 ·10-8 to 0.35 · 10-8 cm 2 /s for the grist in the form of plate, or with 10.4·10-8 – 0.59·10-8 cm 2 /s for the grist in the form of a cylinder

REŠAVANJE JEDNOG PROBLEMA U ORGANSKOJ HEMIJI METODOM EKVIVALENTNIH JEDNAČINA

U teorijskoj organskoj hemiji, zakoni molekulsko – orbitalne teorije omogućuju da se odrede energetska stanja π – elektrona u konjugovanim (nezasićenim) jedinjenjima. Pri ovome energetski nivoi elektrona, dobijaju se razvijanjem odgovarajuće determinante koja se formira koristeći tri karakteristične matrice po definiciji. Svakom jedinjenju, pri ovome pridružuje se odgovarajući polinom, dok će energetski nivoi zavisiti od njegovih nula. Kod velike većine jedinjenja koja se susreću u teoriji i praksi, dobijeni polinom uvek ima bar jednu racionalnu nulu pa se problem rešava jednostavno metodom faktorizacije. Problem nastaje kada karakteristični polinom nema ni jednu racionalnu nulu. U ovom slučaju moguća je primena gotovih matematičkih formula koje su međutim nepodesne za praktičnu upotrebu. Isto tako moguća je i primena numeričkih metoda, koje daju samo približno realno rešenje koje nije pogodno za primenu s obzirom da se gotovo uvek traži tačno realno rešenje. Uzimajući u obzir predhodno, u radu biće dat predlog za rešavanje gore navedenog problema na bazi formiranja ekvivalentnih jednačina preko odgovarajućih matematičkih transformacija, koje omogućuju da se na relativno jednostavan način dobiju tačno sve realne nule polinoma. U prikazanom radu, rešavanje matematičkog problema biće ilustrovano na nekoliko karakterističnih primera. Tačnost dobijenih rezultata prema predloženoj metodi biće izvedena poređenjem sa približnim numeričkim rešenjem koristeći odgovarajući računarski program, odnosno numeričke metode

A model for reliability analysis and calculation applied in an example from chemical industry

The subject of the paper is reliability design in polymerization processes that occur in reactors of a chemical industry. The designed model is used to determine the characteristics and indicators of reliability, which enabled the determination of basic factors that result in a poor development of a process. This would reduce the anticipated losses through the ability to control them, as well as enabling the improvement of the quality of production, which is the major goal of the paper. The reliability analysis and calculation uses the deductive method based on designing of a scheme for fault tree analysis of a system based on inductive conclusions. It involves the use standard logical symbols and rules of Boolean algebra and mathematical logic. The paper eventually gives the results of the work in the form of quantitative and qualitative reliability analysis of the observed process, which served to obtain complete information on the probability of top event in the process, as well as objective decision making and alternative solutions