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Elementy rachunkowości zarządczej w procesie realizacji kontraktu budowlanego

Leśniak Agnieszka, Kołodziejczuk Mirosław

Przegląd Budowlany

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2023

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R. 94, nr 9-10

47--51

PL

Rachunkowość zarządcza dostarcza narzędzi pozwalających osiągnąć sukces finansowy podejmowanej działalności gospodarczej. Praktyką wielu firm budowlanych jest budżetowanie wykonywanych przedsięwzięć. Na podstawie dobrze opracowanego budżetu na każdym etapie realizacji kontraktu budowalnego możliwa jest jego analiza, zarówno pod względem terminu, jak i ponoszonych kosztów, wykonanej produkcji i jej sprzedaży. W artykule wskazano istotę tworzenia budżetu kontraktu budowlanego oraz zwrócono uwagę na funkcję analizy odchyleń kosztów jako metody kontroli jego wykonania.

EN

Management accounting provides the tools to achieve financial success of the business undertaken. The practice of many construction companies is to budget the projects performed. On the basis of a well-developed budget at each stage of the implementation of a construction contract, it is possible to analyze it, both in terms of timing and costs incurred, production performed and its sales. The article points out the essence of creating a budget for a construction contract and draws attention to the function of cost variance analysis as a method of controlling its execution.

2

Suppression of rotating machine shaft-line torsional vibrations by a driving asynchronous motor using two advanced control methods

Hańczur Paweł, Szolc Tomasz, Konowrocki Robert

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 6

art. no. e147925

EN

Many industrial rotating machines driven by asynchronous motors are often affected by detrimental torsional vibrations. In this paper, a method of attenuation of torsional vibrations in such objects is proposed. Here, an asynchronous motor under proper control can simultaneously operate as a source of drive and actuator. Namely, by means of the proper control of motor operation, it is possible to suppress torsional vibrations in the object under study. Using this approach, both transient and steady-state torsional vibrations of the rotating machine drive system can be effectively attenuated, and its precise operational motions can be assured. The theoretical investigations are conducted by means of a structural mechanical model of the drive system and an advanced circuit model of the asynchronous motor controlled using two methods: the direct torque control – space vector modulation (DTC-SVM) and the rotational velocity-controlled torque (RVCT) based on the momentary rotational velocity of the driven machine working tool. From the obtained results it follows that by means of the RVCT technique steady-state torsional vibrations induced harmonically and transient torsional vibrations excited by switching various types of control on and off can be suppressed as effectively as using the advanced vector method DTC-SVM.

3

Construction deviation control method of transverse super large inclined asphalt pavement

Qi Yongzheng, Ma Wengang, Zhang Jiesheng

Archives of Civil Engineering

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2023

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Vol. 69, nr 2

165--176

EN

The speed of test vehicles on the high-speed car track of the automobile test field is very high. Reducing the construction error of asphalt pavement is very important to ensure the safety of the test vehicle. In order to realize the paving of asphalt concrete pavement with super-large lateral inclination in the curve section of the high-speed car track in the automobile test field, a special paving control device and control method for the construction on the curve section with super-large lateral inclination were developed. Use the direction of the hanging hammer under the GPS device of paver to adjust the position of GPS device in real time, so that the geometric centre line of GPS device is always perpendicular to the horizontal plane. The reference control line is preset in the paver operation control device, and the lateral displacement deviation of the paver is adjusted to synchronize the data of the paver control device with the travel route. The precise control of the paver’s forward route is realized, the construction precision of the super-large inclined asphalt pavement on the high-speed car track of the automobile test field is achieved, and the construction efficiency is greatly improved. It has important reference value for similar projects such as automobile testing field and racing track.

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The investigation of the optimization scheme of the low‑cycle fatigue cropping based on the acoustic emission technique

Ren Yujian, Li Jingxiang, Dong Yuanzhe, Zhao Shengdun, Liu Boyang, Jin Dong

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 2

art. no. e61, 1--15

EN

Low-cycle fatigue cropping (LCFC) is a new metal bar separation method which utilizes the material fracture under cyclic load. To achieve good and fast separation of metal bars, a control scheme based on characteristics of whole cropping process is necessary. Three kinds of materials, such as 16Mn, 1045 and Al 6061, have been operated in this study and found that the kurtosis is more suitable as a monitoring parameter in control method, because it has a better stability in the complicated industrial environment. In addition, crack instability stage formed the most uneven region on the section and the best time when change the frequency is before crack instability stage. According to the above results, an optimal control scheme which by reducing the loading frequency before the crack instability stage based on the acoustic emission kurtosis is proposed. Moreover, four control strategies’ results for three kinds of materials are compared, and find the section quality increases with the decrease of loading frequency, but the effect of this increase decreases with the decrease of loading frequency. To evaluate the advantages and disadvantages of the control strategy, a parameter combining efficiency and section quality is proposed, and according to this parameter, the most suitable control strategy for three materials is obtained.