Analysis on Insulation Resistance Performance in Airport Lighting Circuit

The airfield lighting circuits are the important part of the airfield lighting system, and the insulation performance of the circuits directly affects the aircraft flight safety. The side insulation performance of the lighting circuit and the effect of the temperature and humidity on the insulation are analyzed in the paper. Depending on the measure data provided by the Shanghai PUDONG international airport, the curve of circuit insulation resistance changed with the time is fitted through computer, and the insulation resistance mode based on the parameter identifying is obtained. The theoretical foundation is laid for the forecast decline of insulation resistance, and a theoretical basis is provided for the maintenance of the lighting circuit.

FUZZY CONTROL OF PARTNERING RELATIONS OF A CONSTRUCTION ENTERPRISE / STATYBOS ĮMONĖS PARTNERYSTĖS SANTYKIŲ NEAPIBREŽTUMO KONTROLĖ

The author has elaborated an expert system to control partnering relations with a construction enterprise. The expert system is based on Mamdani fuzzy model. The purpose of the system is to improve the indices of assessing a construction enterprise by raising the level of partnering relations with other transactors in industry. The system indicates a recommendation supporting a decision-making system of any given construction enterprise and stating whether relations are to be preserved, changed or changed immediately to each of the fourteen relation parameters and for each of four transactors of enterprise's microenvironment. For every relation parameter, this decision is taken by the expert system with reference to the significance and assessment of this parameter identifying its influence on the success of a construction enterprise. Another task of the expert system is to select one parameter for each transactor which needs to be changed first. The process of choosing the parameter to be changed first for a given transactor is based on all input parameters. Santrauka Autorė sukūrė ekspertinę sistemą, padedančią kontroliuoti partnerystės santykius statybos įmonėje. Ekspertinė sistema pagrįsta Mamdani neapibrėžtumo modeliu. Šios sistemos tikslas—pagerinti statybos įmonės rodiklius keliant partnerystės santykių su kitais pramonės dalyviais lygį. Sprendimų paramos sistema, kuri gali būti taikoma bet kurioje statybos įmonėje, teikia rekomendacijas ir nurodo, ar partnerystės santykiai su kiekvienu iš keturių įmonės mikroaplinkos dalyvių turi būti išsaugoti, ar pakeisti, ar skubiai pakeisti, atsižvelgiant į kiekvieną iš keturiolikos santykius apibrėžiančių parametrų. Ekspertinė sistema priima sprendimus pagal kiekvieną santykius apibrėžiantį parametrą, atsižvelgiant į parametro reikšmingumą statybos įmonės veiklos sėkmei. Kitas ekspertinės sistemos uždavinys—parinkti kiekvienam dalyviui po vieną santykius apibrėžiantį parametrą, kuris turi būti pakeistas pirmiausia. Parametras, kuris turi būti pakeistas pirmiausia tam tikram dalyviui yra parenkamas atsižvelgiant į visus įvesties parametrus.

Moving Sheet With Variable Thermal Conductivity Emerging From a Slot

In this work, we treat the heat transfer process of a continuously moving flat sheet with variable thermal conductiviy, emerging from a slot in contact with a quiescent fluid. Due to the thermal conductivity of the sheet, strong longitudinal and transverse temperature gradients arise within it, requiring to solve simultaneously the energy equation of the sheet and fluid equations. The momentum and energy balance equations are reduced to a non-linear system of partial differential equations with four parameters: the Prandtl number, Pr, a non-dimensional sheet thermal conductance β, a non-dimensional parameter identifying the effect of the variable thermal conductivity γ and a suitable Peclet number, Pe. For finite values of the parameter γ we recognize the limits β≪1 and βPe2≪1 as the most relevant from a practical point of view. In this case, the problem is governed by an universal integro-differential equation in order to obtain the spatial evolution of the sheet temperature as a function of the nondimensional longitudinal coordinate.