Pietraszek, Jacek, Sobczyk, Andrzej, Skrzypczak-Pietraszek, Ewa, Kołomycki, Maciej
Abstract:The well-known statistical tests have been developed on the basis of many additional assumptions, among which the normality of a data source distribution is one of the most important. The outcome of a test is a p-value which may is interpreted as an estimation of a risk for a false negative decision i.e. it is an answer to the question “how much do I risk if I deny?”. This risk estimation is a base for a decision (after comparing with a significance level α): reject or not. This sharp trigger – p-level greater than α or not – ignores the fact that a context is rather smooth and evolves from “may be” through “rather not” to “certainly not”. An alternative option for such assessments is proposed by a fuzzy statistics, particularly by Buckley’s approach. The fuzzy approach introduces a better scale for expressing decision uncertainty. This paper compares three approaches: a classic one based on a normality assumption, Buckley’s theoretical one and a bootstrap-based one.
Abstract:The paper is concerned with the performance properties of electro-spark deposited coatings. The properties were assessed by analyzing the coating microstructure, X-ray diffraction, microgeometry, microhardness, and corrosion tests. The studies were conducted using WC-Co-Al2O3 electrodes produced by the sintering of powders. The anti-wear coatings were electrospark deposited over C45 carbon steel by means of an EIL-8A. These coatings are likely to be applied in sliding friction pairs and as protective coatings.
Abstract:McKibben pneumatic artificial muscles (PAMs) allow for a proper representation of static and dynamic movement characteristics of biomechanical systems. These actuators have features similar to physiological muscles such as ability to generate high value of force in short time and elastic and damping properties. McKibben muscles have a nonlinear character – the value of a generated force depends not only on the pressure but also on the stroke. In the presented paper, the authors exemplify basic traits of these actuators and present drawn characteristics of a force to stroke at a constant pressure.
Abstract:This paper presents the modelling of a direct acting relief valve with the use of the new approach of CFD techniques which uses the Lattice Boltzman Method (LBM). It allows for eliminating the biggest problem that occurs during the simulation of a valve operation, which is the motion of a working component. During traditional CFD modeling, a deformed mesh has to be used in such a case, which may lead to the occurrence of computational cells with negative volume and, as a consequence, remeshing of fluid domain.
Abstract:Shainin’s approach is a specific sequential heuristic aimed at finding and ranking the most important factors which impact the investigated process. The sequential aspect of the approach is simultaneously its strongest and weakest side, because just after detection of the most important factor, the further analysis is stopped without any additional cost. However, such a detection may take place at the end of the whole sequence. This paper tries to answer the question if the dominant factor may be hidden by interactions with other factors.
Abstract:This article analyzes screw connection of slewing bearings to various structures of support elements. The susceptibility of support elements to the load distribution in particular bearing screws was examined by means of the Finite Element Method. The load values of screws and their distribution around the perimeter of the combined bearing rings were also specified.
Abstract:The paper presents models for designing of information systems for manufacturing. Chosen model of system implementation has a significant impact on the quality and performance of the target solution. Special focus is on the data model layer and the possibility of changing the standard three-tiered model of information systems through increased utilisation of resources of database server.
Abstract:Basic requirements for modern machine elements include the improvement of durability alongside the reduction of the cost of materials. This entails the need for the manufacturing process to ensure a stable geometric form of those elements. This analysis aims at developing loading schemes for the dynamic stabilization stand designed for the straightening of the discs buckled as a result of hardening heat treatment [1, 2].
Pietraszek, Mariusz, Klemba, Tomasz, Lubieniecka, Joanna, Łukasiewicz, Jerzy, Pietraszek, Jacek
Abstract:This paper describes a part of research related to the elimination of adverse phenomenon involving the occurrence of a negative oxygen balance of combustion products of missile engines during their firing from aircrafts. It also presents the results of comparative tests of rocket engines equipped with an additional oxidizer charge.
Abstract:Diversification strategy is currently used by enterprises to increase their stability and economic condition. It is not easy to realize the measurement of the process. The application of the parameter of entropy, which is well-known is physics, is one idea of parametrization. In the machinery industry, product diversification is connected with different consumers representing factories from different machinery sectors: mining, steel, building, agricultural and food. The possibility of estimation of the production diversification in the machinery industry by the application of the entropy-based parameters is discussed in the paper.