Wyniki wyszukiwania - BazTech

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Urządzenie do obcinania dennic

Sawicki Tadeusz

Napędy i Sterowanie

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2019

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R. 21, nr 9

165--166

PL

Zdecydowana większość wykonywanych dennic, służących do produkcji zbiorników i cystern, wytwarzana jest metodą tłoczenia na gorąco. Dennica wytłoczona na gorąco nie jest idealnie okrągła i zawsze posiada naddatek na obcięcie. Średnicę dennicy po tłoczeniu wyznacza się z obwodu, tj. mierząc obwód i dzieląc przez liczbę π, otrzymujemy wymagany wymiar. Wysokość dennic jest ściśle regulowana normami i przepisami i uzyskuje się ją po obcięciu.

EN

A considerable number of dished ends of cylindrical tanks, silos and pressure vessels is produced by hot forming. The surplus material obtained in this process needs to be trimmed off for the dished ends to meet the design requirements and conform to the design standards. This is usually achieved by using specialised flanging machines. The two main functional components of these machines are the cutting torch and the carriage platform. The cutting torch must have provisions for being precisely positioned against the flange. The carriage platform must enable smooth movement of the dished ends at a range of angular speeds, thus facilitating accurate operation of the cutting torch. Apart from ensuring dimensional specifications are met, flanging machines often enable a chamfer to be applied to the edge of the flange.

2

On truncations for weakly ergodic inhomogeneous birth and death processes

Zeifman A., Satin Y., Korolev V., Shorgin S.

International Journal of Applied Mathematics and Computer Science

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2014

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Vol. 24, no. 3

503--518

EN

We investigate a class of exponentially weakly ergodic inhomogeneous birth and death processes. We consider special transformations of the reduced intensity matrix of the process and obtain uniform (in time) error bounds of truncations. Our approach also guarantees that we can find limiting characteristics approximately with an arbitrarily fixed error. As an example, we obtain the respective bounds of the truncation error for an Mt/Mt/S queue for any number of servers S. Arbitrary intensity functions instead of periodic ones can be considered in the same manner.

3

Semi-Markov-based approach for the analysis of open tandem networks with blocking and truncation

Oniszczuk W.

International Journal of Applied Mathematics and Computer Science

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2009

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Vol. 19, no 1

151-163

EN

This paper describes an analytical study of open two-node (tandem) network models with blocking and truncation. The study is based on semi-Markov process theory, and network models assume that multiple servers serve each queue. Tasks arrive at the tandem in a Poisson fashion at the rate [...], and the service times at the first and the second node are nonexponentially distributed with means sA and sB, respectively. Both nodes have buffers with finite capacities. In this type of network, if the second buffer is full, the accumulation of new tasks by the second node is temporarily suspended (a blocking factor) and tasks must wait on the first node until the transmission process is resumed. All new tasks that find the first buffer full are turned away and are lost (a truncation factor). First, a Markov model of the tandem is investigated. Here, a twodimensional state graph is constructed and a set of steady-state equations is created. These equations allow calculating state probabilities for each graph state. A special algorithm for transforming the Markov model into a semi-Markov process is presented. This approach allows calculating steady-state probabilities in the semi-Markov model. Next, the algorithms for calculating the main measures of effectiveness in the semi-Markov model are presented. In the numerical part of this paper, the author investigates examples of several semi-Markov models. Finally, the results of calculating both the main measures of effectiveness and quality of service (QoS) parameters are presented.