Wyniki wyszukiwania - BazTech

1

Optimal transmission expansion planning considering distributed generations by using non-dominated sorting genetic algorithm-II (NSGAII)

Kamarposhti Mehrdad Ahmadi, Kabalci Ersan

Journal of Power Technologies

|

2021

|

Vol. 101, nr 1

70--77

EN

Reconstructing power systems has changed the traditional planning of power systems and has raised new challenges in Transmission Expansion Planning (TEP). Because of these reason, new methods and criteria have been formed for planning transmission in reconstructed environments. Thus, a dynamic programming was used for transmission efficiency based on multi-objective optimization in this research. In this model, investment cost, cost of density and dependability have been considered three objectives of optimization. In this paper, NSGAII multi-objective genetic algorithm was used to solve this non-convex and mixed integer problem. A fuzzy decision method has been used to choose the final optimal answer from the Pareto solutions obtained from NSGAII. Moreover, to confirm the efficiency of NSGAII multi-objective genetic algorithm in solving TEP problem, this algorithm was implemented in an IEEE 24 bus system and the gained results were compared with previous works in this field.

2

Effects of Precipitation Hardedning in Co-Ni-Cr Alloy on Dissipative Motion of Dislocations by Amplitude-Dependent Internal Friction Measurements

Cosimati R., Mari D.

Archives of Metallurgy and Materials

|

2015

|

Vol. 60, iss. 4

3077--3082

EN

The effects of precipitation hardening occurring in a Co-Ni-Cr alloy after annealing treatments have been studied by using mechanical spectroscopy. The amplitude-dependent internal friction (ADIF) due to the dissipative motion of dislocations reveals the presence of a threshold strain for weakly pinned dislocations. The change of ADIF curves and the increase of the elastic modulus after thermal cycles producing precipitates suggest that dislocations motion is hindered leading to increasing strength of the material. Precipitation is confirmed by the changes of thermoelectric power (TEP) and by hardness measurements showing a hardness increase at the same temperature as the maximum in TEP curve. The ADIF spectra as well as the interaction between dislocations and precipitates are interpreted by proposing a phenomenological model based on the Granato-Lücke theory.

PL

Wpływ utwardzania wydzieleniowego występującego w stopie Co-Ni-Cr po wyżarzaniu zbadano za pomocą spektroskopii mechanicznej. Wewnętrzne tarcie zależne od amplitudy (ADIF) ze względu na rozpraszający ruch dyslokacji ujawnia obecność naprężenia granicznego dla słabo zakotwiczonych dyslokacji. Zmiana krzywych ADIF i wzrost modułu sprężystości po obróbce cieplnej wytwarzającej wydzielenia wskazują, że ruch dyslokacji jest utrudniony prowadząc do zwiększenia wytrzymałości materiału. Wydzielenia są potwierdzone przez zmiany siły termoelektrycznej i pomiary twardości, wykazujące zwiększenie twardości w tej samej temperaturze, co maksimum na krzywej TEP. Widma ADIF, a także oddziaływania między dyslokacjami i wydzieleniami są interpretowane przez proponowany fenomenologiczny model oparty na teorii Granato-Lücke.

3

The role of surface and bulk structure in the thermopower characterization of perlitic carbon steels

Szabo A., Lovas A.

International Journal of Applied Mechanics and Engineering

|

2010

|

Vol. 15, no 2

349-354

EN

For the study of stress state and the level of heat treatment in engineering alloys, the thermo power (S) measurement is proposed as an acceptable method after a suitable calibration. In this paper, we focus on the determination of the influence of phase relations from the point of view of thermo power using industrial pearlitic carbon steels. The results of thermoelectric power measurements reported in this paper do confirm the applicability of S (T) measurements as non-destructive testing of quench hardening in pearlitic steels.