Wyniki wyszukiwania - BazTech

1

Optimization of drilling parameters for aluminum metal matrix composite using entropy-weighted TOPSIS under MQL conditions

Ghalme Sachin G., Karolczak Paweł

Engineering Transactions

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2023

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Vol. 71, iss. 4

595--616

EN

The aim of the present work is to understand the effect of drilling parameters (drill speed and feed rate) during the drilling of a Saffil fiber-reinforced Al metal matrix composite (MMC) under minimum quantity lubrication (MQL) condition. The effect of drilling parameters on individual response characteristics is evaluated and the optimum drilling parameters are also investigated using a multi-response optimization technique known as the entropy-weighted technique for order performance by similarity to ideal solution (EWTOPSIS). The drilling parameter optimization is performed with the aim of minimizing surface roughness in the drilled hole, roundness error in the drilled hole and feed force during drilling. The drilling parameters have a significant effect on individual responses. Weights were assigned to each response using the entropy weight method, and closeness coefficients were calculated to obtain the optimal level for the drilling parameters. A drill speed of 11 m/min and a feed rate of 0.05 mm/rev are the optimal combination to minimize the desired output responses simultaneously.

2

Multi-objective optimization of PCM-fin structure for staggered Li-ion battery packs

Qiu Chenghui, Wu Chongtian, Yuan Xiaolu, Wu Linxu, Yang Jiaming, Shi Hong

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 4

art. no. e145677

EN

Endurance capability is a key indicator to evaluate the performance of electric vehicles. Improving the energy density of battery packs in a limited space while ensuring the safety of the vehicle is one of the currently used technological solutions. Accordingly, a small space and high energy density battery arrangement scheme is proposed in this paper. The comprehensive performance of two battery packs based on the same volume and different space arrangements is compared. Further, based on the same thermal management system (PCM-fin system), the thermal performance of staggered battery packs with high energy density is numerically simulated with different fin structures, and the optimal fin structure parameters for staggered battery packs at a 3C discharge rate are determined using the entropy weight-TOPSIS method. The result reveals that increasing the contact thickness between the fin and the battery (X) can reduce the maximum temperature, but weaken temperature homogeneity. Moreover, the change of fin width (A) has no significant effect on the heat dissipation performance of the battery pack. Entropy weight-TOPSIS method objectively assigns weights to both maximum temperature (Tmax) and temperature difference (DT) and determines the optimal solution for the cooling system fin parameters. It is found that when X = 0:67 mm, A = 0:6 mm, the staggered battery pack holds the best comprehensive performance.

3

Facilitating optimal operations of a wave energy converter using a preeminent mooring line: an entropy weight-VIKOR method

Nwaoha Thaddeus C., Udosoh Nsisong E.

Journal of Mechanical and Energy Engineering

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2022

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Vol. 6, No 1

77--83

EN

This study employed viable methods for the selection of a preeminent mooring line amongst other alternatives for the mooring of a floating wave energy converter (WEC) in shallow waters. Conventional mooring lines for WEC mooring are identified for an optimal selection exercise. A combination of the Entropy Weight and Visekriterijumska Optimizacijia I Kompromisno Resenje (VIKOR) methods is utilized in the aforementioned exercise. The two methods are effectively used in an assessment of the attributes and performance of various mooring lines in practical application. The result obtained demonstrated that a steel wire rope is the best mooring line suitable for WEC system operations. It constitutes a good reference to marine and offshore engineering industries in decision making related to optimal mooring lines suitable for the mooring of a WEC system in shallow waters.

4

New Mixed Weibull Probability Distribution Model for Reliability Evaluation of Paper-oil Insulation

He Z., Wang Y., Li J., Gong S., Grzybowski S.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 1a

202--206

EN

This paper presents a new mixed Weibull probability distribution model for reliability evaluation of the paper-oil insulation. The breakdown voltage, furfural, and six other characteristic parameters were chosen to reflect the reliability of paper-oil insulation. The new mixed Weibull probability distribution model was established to evaluate the reliability of the paper-oil insulation. Reliability predictions of the paper-oil insulation at different times verified the feasibility of the new mixed Weibull probability distribution model.

PL

W artykule przedstawiono metodę budowy modelu rozkładu prawdopodobieństwa Weibulla, w wykorzystaniu do oceny niezawodności izolacji papierowo-olejowej. Wykorzystywanych jest osiem parametrów dotyczących niezawodności. Wykonane przewidywanie niezawodności dla różnych odległości czasowych potwierdzają skuteczność metody.