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1

Optimization model the pipe diameter in the drinking water distribution network using multi-objective genetic algorithm

Sulianto, Setiono Ernawan, Yasa I. Wayan

Journal of Water and Land Development

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2021

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no. 48

55--64

EN

Under conditions of gravity flow, the performance of a distribution pipe network for drinking water supply can be measured by investment cost and the difference in real and target pressures at each node to ensure fairness of the service. Therefore, the objective function for the optimization in the design of a complex gravity flow pipe network is a multi-purpose equation system set up to minimize the above-mentioned two parameters. This article presents a new model as an alternative solution to solving the optimization equation system by combining the Newton–Raphson and genetic algorithm (GA) methods into a single unit so that the resulting model can work effectively. The Newton–Raphson method is used to solve the hydraulic equation system in pipelines and the GA is used to find the optimal pipe diameter combination in a network. Among application models in a complex pipe network consisting of 12 elements and 10 nodes, this model is able to show satisfactory performance. Considering variations in the value of the weighting factor in the objective function, opti-mal conditions can be achieved at the investment cost factor (ω1) = 0.75 and the relative energy equalization factor at the service node (ω2) = 0.25. With relevant GA input parameters, optimal conditions are achieved at the best fitness value of 1.016 which is equivalent to the investment cost of USD 56.67 thous. with an average relative energy deviation of 1.925 m.

2

Influence of pick layouts on the performance of bolter miner cutting head

Qiao S., Wang A. L., Xia Y. M., Liu Z. Z., Liu J. S., Yang M.

Mining Science

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2018

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Vol. 25

147--160

EN

A bolter miner is a new type of mining machinery with cutting and anchoring functions. In order to study the best pick layout of bolter miner cutting head. Based on the constitutive relation of Holmquist-Johnson-Cook (HJC), three simulation models of different cutting heads were established, and the whole crushing process of coal-rock was simulated by finite element method (FEM). The influence of the cutting head on the cutting performance under the condition of different rotational speeds and pick layouts was intensively studied. The results show that the relationship of load fluctuation coefficient among the three pick layouts is as follows: sequential type > hybrid type I > checkerboard type. The circumferential pick layouts can reduce the load fluctuation coefficient of cutting head. The rotational speed from 20 to 40 r/min, the torque linearly decreases with the increase of rotational speed. The rota-tional speed increases from 40 to 50 r/min, the cutting torque is relatively stable. The specific energy of chessboard type is relatively higher than the other three cutting heads. The difference of specific energy between sequential type and hybrid type I is not more than 5.5%, and the reality of the simulation is verified by cutting experiments. The results were successfully applied to the first shield type bolter miner in China.

3

Context of the inventory management expenses in the case of planned shortages

Korponai J., Tóth Á. B., Illés B.

Engineering Management in Production and Services

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2017

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Vol. 9, no. 1

26--35

EN

The main purpose of the paper is to present the relations between the different cost factors of the inventory management systems, and the context between the order quantities and the cost level. The theoretical approach of the model assumes a deterministic operational environment with planned shortages. We make the examination of the contexts by applying the ceteris paribus principle; we change only one cost factor from among the initial conditions at once and examine its effect on the cost level. By using the economic order quantity with the planned shortage model, we can define the optimal order quantity, along which our stock management can be guaranteed by the most favourable cost level. The optimisation of the inventory level and the inventory management expenses together means an important factor in the competitiveness of the company. During the definition of the optimal inventory level of purchased parts, the purchasing and stock holding costs, and also the consequence of shortages play an important role. The presentation of the specific expense factors in each other’s function, and the representation of the onetime order expenses show their proportion compared to each other and the effect of their change on the total cost, and define the opportunities of the optimisation. The significance of the model is that it represents the level line of costs, the movement of the different cost factors in relation to others and their operating mechanism. Thus, it facilitates the representation of costs and the definition of the direction of optimisation.

4

The optimal online control of the instantaneous power and the multiphase source’s current

Siwczyński M., Hawron K.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2017

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Vol. 65, nr 6

827--832

EN

The paper presents the new optimal real-time control algorithm of the power source. The minimum of the square-instantaneous current was assumed as an optimal criterion, with an additional constraint on source instantaneous power. The mathematical model of a multiphase source was applied as a voltage-current convolution in the discrete time domain. The resulting control algorithm was the recursive digital filter with infinite recursion.

5

Determining optimum volume of cold and hot blast air in single--row coke cupolas

Khatemi B., Longa W.

Metallurgy and Foundry Engineering

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2005

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Vol. 31, No 1

53-65

EN

In this study a formula was derived to calculate optimum volume of cupola blast air [formula), standard operating conditions], cold or hot, for single-row coke cupolas, assuming that the lower boundary of the melting zone is adhacent to the upper boundary of the combustion zone (the condition of optimum cupola running formulated by A. Achenbach in 1931). Relevant equations and tables have also been developed to make the calculations easier. From computations made in this study it follows that the optimum blast air volume is increasing with an increase of the blast air temperature, assuming for cold blast a value close to [formula] (Buzek postulate), with modulus of the metallic charge lumps changing in a range of 15 to 20 mm.

PL

W pracy wyprowadzono wzór do obliczania optymalnej ilości powietrza dmuchu [wzór), warunki normalne], zimnego lub podgrzanego, dla żeliwiaków koksowych jednorzędowych, przy założeniu, że dolna granica strefy topienia przylega do górnej granicy strefy spalania (warunek optymalnego biegu żeliwiaków, sformułowany przez A. Achenbacha w 1931 roku). Opracowano również wzory i tablice ułatwiające obliczenia. Z przeprowadzonych obliczeń wynika, że ze wzrostem temperatury powietrza dmuchu rośnie optymalna ilość powietrza dmuchu, przy czym dla zimnego dmuchu oscyluje ona około wartości [wzór] - postulat Buzka, przy zmianie modułu kawałków wsadu metalowego w zakresie od 15 do 20 mm.

6

Współczynnik sprawności energetycznej jako ocena systemu tribologicznego w obróbce plastycznej

Suwart R.

Tribologia

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2003

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nr 6

59-72

PL

Praca stanowi wycinek badań wykonanych przez autora związanych z technologią wyciskania tulejek stalowych. Wykazano przydatność stosowania współczynnika sprawności energetycznej do oceny systemu tribologicznego w procesach obróbki plastycznej metali. Współczynnik określa stosunek pracy (wyliczonej w oparciu o dewiator naprężenia) niezbędnej do odkształcenia plastycznego danej objętości do pracy rzeczywistej, jaką wykonuje się na stanowisku produkcyjnym. Współczynnik pozwala optymalizować procesy obróbki plastycznej metali.

EN

A work introduces a fragment of scientific researches, which were realized by author and which are technology of bushes extrusion pertinently. It was proved, that the coefficient of energy efficiency is useful for the valuation of tribology system in metal forming processes. The coefficient describes work ratio (that was counted on basis of intensity of stress deviator), which is necessary to volume deformation, to real work, which is realized at work station. The coefficient allows to metal forming optimization.

7

Deformation processing map for CuAl8.1Fe2.9 aluminium bronze.

Gronostajski Z.

Inżynieria Materiałowa

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2001

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R. XXII, nr 4

365-368

PL

Naprężenie uplastyczniające brązu aluminiowego CuAl8.1Fe2.9 wyznaczane w próbie skręcania w szerokim zakresie temperatur i prędkości odkształcania było analizowane przy użyciu dynamicznego modelu materiału. Model ten rozpatruje materiał odkształcany w podwyższonych temperaturach jako dyssypator mocy. Mapa efektywności procesów, reprezentująca dyssypację mocy w funkcji temperatury i prędkości odkształcania, została opracowana i na jej podstawie ustalone zostały obszary w których zachodzą procesy rekrystalizacji dynamicznej i dynamicznego zdrowienia oraz optymalne warunki odksztacania.

EN

The flow stress data obtained in torsion test of CuAl8.1Fe2.9 aluminium bronze at different temperatures and strain rate are analysed using dynamic material's model which considers the workpiece as a power dissipator. A processing map representing the efficiency of power dissipation as a function of temperature and strain rate has been established and areas of dynamic recovery and recrystallization processes as well as optimum processing conditions for the aluminium bronze was determined.

8

Pro optimal'ne roztashuvannja mas na konsolih pri avtokolivnihjj vtratih stihjjkostih

Tacihjj R., Davidchak O.

Zeszyty Naukowe Politechniki Rzeszowskiej. Budownictwo i Inżynieria Środowiska

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2000

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z. 32[180], cz.1

547-550

EN

Equilibrium stability of a cantilever under the action of following force, taking into account distributed and concentrated point masses has been investigated using a solution of the generalized quasi-differential equation. The investigations to have been carried out show dependence of a critical force value on arrangement of the concentrated masses on the column for the cantilevers with distributed masses and either one concentrated mass or two concentrated ones. The results of the investigations given in the article point places for the optimum arrangement of the concentrated mass according to the critical force value. The algorithm of the investigation of a cone column with any quantity of concentrated masses is submitted as well.