30 research outputs found

    Mathematical model of energy efficiency in internal spur gears

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    The impact of geometric parameters of teeth and lubricating oils to the efficiency of involute internal spur gears, when the transverse contact ratio is 2 lt epsilon(alpha) lt = 3, has been analyzed in this paper. The mathematical model and computer program for determining the current and the effective value of the efficiency have been developed. The influence of the character of load distribution and energy losses due to heating effects during the meshing period is included in the factor of load distribution. The results of computer simulation are given in the form of a diagram of the current values of the efficiency during the meshing period. Also, the values of effective efficiency for the considered cylindrical gear pairs have been calculated

    Mathematical model of energy efficiency in internal spur gears

    Get PDF
    The impact of geometric parameters of teeth and lubricating oils to the efficiency of involute internal spur gears, when the transverse contact ratio is 2 lt epsilon(alpha) lt = 3, has been analyzed in this paper. The mathematical model and computer program for determining the current and the effective value of the efficiency have been developed. The influence of the character of load distribution and energy losses due to heating effects during the meshing period is included in the factor of load distribution. The results of computer simulation are given in the form of a diagram of the current values of the efficiency during the meshing period. Also, the values of effective efficiency for the considered cylindrical gear pairs have been calculated

    Green analytical approach for extraction and chemical profiling of phenolic compounds from natural products: A case study of Teucrium chamaedrys L.

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    One of the main principles of green analytical chemistry is to eliminate or reduce the use of organic solvents and reagents, and therefore use of Natural Deep Eutectic Solvents (NADES) as medium in sample extraction was recognized as green alternative to conventional one. In this paper, 19 different natural deep eutectic solvents were used for the extraction of phenolic compounds from Teucrium chamaedrys L. Chemical profiles of the extracts were obtained by applying high-performance thin-layer chromatography (HPTLC), which is a green technique due to the simultaneous analysis of a large number of samples, using small amounts of extracts and minimal amounts of solvents. Greenness of proposed methodology was estimated by NEMI pictogram and analytical eco-scale.Jedan od glavnih ciljeva zelene analitičke hemije je eliminisanje ili smanjenje upotrebe organskih rastvarača i reagenasa i zbog toga je primena prirodnih eutektičkih smeša (NADES - natural deep eutectic solvents) kao medijuma za ekstrakciju uzoraka prepoznata kao zelena alternativa. U ovom radu je primenjeno 19 različitih prirodnih eutektičkih smeša za ekstrakciju fenolnih jedinjenja iz biljke podubice. Za hemijsko profilisanje ekstrakata korišćena je visoko-efikasna tankoslojna hromatografija (HPTLC – High-performance thin-layer chromatography) koja predstavlja zelenu tehniku zbog istovremene analize velikog broja uzoraka, uz upotrebu male količine ekstrakata i minimalnih količina rastvarača. Ekološka prihvatljivost predložene metodologije procenjena je primenom Nacionalnog indeksa uticaja metode na životnu sredinu i eko-skale

    Integrating Archaeological Theory and Predictive Modeling: a Live Report from the Scene

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    Program ispitivanja i metodologija analize spektra vibracija brodske gasne turbine Proteus 52M/558 / The test programme and the methodology of analyzing the vibrations spectrum of a Proteus 52M/558 ship gas turbine

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    The paper presents a programme for testing vibrations on a ship gas turbine, based on an analogy of testing and analysis of vibrations on aircraft and/or helicopter gas turbines. A particular attention is given to a choice of vibration parameters and to the analysis of the vibration spectrum as well as to the methods of estimation of criteria of vibration acceptability. The results of the measurement of the vibrations on a Proteus 52M/558 gas turbine installed on a RTOP-405 ship are shown. / U radu je prikazan program ispitivanja vibracija brodske gasne turbine, zasnovan na analogiji ispitivanja i analizi vibracija na avionskim i/ili helikopterskim gasnim turbinama. Posebna pažnja posvećena je izboru parametara vibracija, analizi spektra vibracija, kao i metodama procene kriterijuma prihvatljivosti vibracija. Na kraju rada prikazani su rezultati merenja vibracija na gasnoj turbini Proteus 52M/558 ugrađenoj na brodu RTOP-405
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