Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 8
items per page: 25 50 75
Sort by:

Abstract

Nickel alloys belong to the group of most resistant materials when used under the extreme operating conditions, including chemically aggressive environment, high temperature, and high loads applied over a long period of time. Although in the global technology market one can find several standard cast nickel alloys, the vast majority of components operating in machines and equipment are made from alloys processed by the costly metalworking operations. Analysis of the available literature and own studies have shown that the use of casting technology in the manufacture of components from nickel alloys poses a lot of difficulty. This is due to the adverse technological properties of these alloys, like poor fluidity, high casting shrinkage, and above all, high reactivity of liquid metal with the atmospheric air over the bath and with the ceramic material of both the crucible and foundry mold. The scale of these problems increases with the expected growth of performance properties which these alloys should offer to the user. This article presents the results of studies of physico-chemical interactions that occur between theH282alloy melt and selected refractory ceramic materials commonly used in foundry. Own methodology for conducting micro-melts on a laboratory scale was elaborated and discussed. The results obtained have revealed that the alumina-based ceramics exhibits greater reactivity in contact with the H282 alloy melt than the materials based on zirconium compounds. In the conducted experiments, the ceramic materials based on zirconium silicate have proved to be a much better choice than the zirconia-silica mixture. Regardless of the type of the ceramic materials used, the time and temperature of their contact with the nickel alloy melt should always be limited to an absolutely necessary minimum required by the technological regime.
Go to article

Abstract

Freedom and Resentment (1962), written by Peter Frederick Strawson, is one of the most influential papers in 20th century investigations regarding the problem of free will. An interesting criticism of that work was proposed by his son, Galen Strawson, who analyzed and rejected his father’s view, called the theory of reactive attitudes. In my paper I reconstruct the views of Peter Strawson and present counterarguments put forward by Galen Strawson. In the summary I suggest, following Robert Kane, that the disagreement may reflect some important changes in analytic philosophy.
Go to article

Abstract

The aim of this study was to measure serum neopterin and C-reactive protein (CRP) concen- trations in female dogs with mammary tumours and evaluate the association between the values of these indicators and some clinical characteristics of the tumour. Fifty three female dogs were used for this study, including 43 dogs with mammary gland tumours (10 benign and 33 malignant) and 10 healthy controls. The concentrations of neopterin and CRP were determined using the ELISA technique and commercial ELISA kits. The mean serum neopterin concentration in fe- male dogs with mammary tumours was lower than in healthy dogs, but significant difference was not found. Similarly, there were no significant differences in neopterin concentrations in female dogs based on tumour size, tumour ulceration and metastasis. The mean CRP concentration was significantly higher (p<0.05) in dogs with malignant tumours compared to dogs with benign tu- mours and control. Furthermore, serum CRP concentration was significantly higher (p<0.05) in dogs with metastatic malignant tumours compared to dogs with non-metastatic mammary tu- mours. The CRP concentration was significantly lower (p<0.05) in dogs with tumours less than 3 cm compared to those with larger tumours, and significantly higher in dogs with ulcerated tu- mours compared to those without ulceration. Our findings suggest that the neoplastic process in the mammary gland does not cause significant changes in serum neopterin concentrations in dogs. Higher concentrations of serum CRP in dogs with advanced stages of malignant tumours may suggest that CRP could be a potential prognostic marker in canine malignant mammary tu- mours, but this hypothesis needs further study.
Go to article

Abstract

The paper focuses on two research objectives. First, it aims to critically examine a reductio ad absurdum argument against incompatibilism whose main themes can be found in Peter F. Strawson’s Freedom and Resentment. The doubts raised about the argument are inspired by a thought experiment based on fictitious Ludovico’s technique described in Anthony Burgess’s novel A Clockwork Orange. The second objective consists in outlining a version of the compatibilist stance – the version which is immune to Strawson’s objections against the traditional rendering of compatibilism and enables deeper understanding of various possible interpretations of the controversy between compatibilists and their opponents. The proposed position includes a hypothesis on the function of the attitude of participation and the expressivist explications of the concepts crucial for the practice of ascribing moral responsibility. The important feature of the analyses in question is the central role of the states of mind whose content are plans for reactive moral sentiments.
Go to article

Abstract

The article presents Peter F. Strawson’s remarks on the free will debate, which he has presented in the essay ‘Freedom and Resentment’. Strawson avoids taking a stance on the question whether the thesis of determinism is correct. Instead he shows the essential difficulties and far reaching consequences of acknowledging this thesis. He recognizes the inseparable connection between freedom and responsibility in the philosophy after Kant. He consequently questions whether we really understand what it would mean to claim that determinism is true. He focuses on what he calls ‘reactiv attitudes’ triggered by the way in which other people behave toward us. Their behavior evokes emotional reaction in us – gratitude, respect, curiosity, but also distrust, resentment, disappointment. Those emotional responses are not purely subjective and they underlie moral judgments and complicated interpersonal relations. We suspend our reactive attitudes towards animals, very small children or people that we think are mentally ill. Instead we adopt objective (psychiatric, scientific) attitudes towards them. But to acknowledge the thesis of determinism implicates that we should treat all people this way. The paper is not so much concerned with an analysis of advantages and weak points of Strawson’s version of compatibilism, but focuses instead on the originality of his contribution to the debate on free will and on his brilliant treatment of reactive attitudes.
Go to article

Abstract

This paper presents the resolution of the optimal reactive power dispatch (ORPD) problem and the control of voltages in an electrical energy system by using a hybrid algorithm based on the particle swarmoptimization (PSO) method and interior point method (IPM). The IPM is based on the logarithmic barrier (LB-IPM) technique while respecting the non-linear equality and inequality constraints. The particle swarmoptimization-logarithmic barrier-interior point method (PSO-LB-IPM) is used to adjust the control variables, namely the reactive powers, the generator voltages and the load controllers of the transformers, in order to ensure convergence towards a better solution with the probability of reaching the global optimum. The proposed method was first tested and validated on a two-variable mathematical function using MATLAB as a calculation and execution tool, and then it is applied to the ORPD problem to minimize the total active losses in an electrical energy network. To validate the method a testwas carried out on the IEEE electrical energy network of 57 buses.
Go to article

Abstract

Freedom and Resentment (1962) – reflecting the method and profoundness of descriptive metaphysics – has become perhaps the most commented and famous work by Peter F. Strawson. In this article I try to reconstruct the concept of responsibility, blame and punishment outlined in his essay. The text consists of three main parts: exhibition (subsections 2, 3), interpretation (4) and criticism (5). In the last part I argue that even if Strawson managed to repulse the pessimistic argumentation against compatibilism, his naturalistic position, as well as the traditional optimism, does not provide the right kind of ethical justification for reactive emotions and attitudes. The nerve of his reasoning is the premise that from the human point of view it is practically inconceivable to abandon them. Therefore, the succes of such argumentation depends on the meaning of practical inconceivability. One can distinguish its naturalistic (referring to the type- or token-naturalism) and transcendental interpretation. The latter, as I try to show, is unable to formally distinguish between the metaphysical and ethical content of Strawson’s position. On the other hand, the logical separation of both views is the main advantage of the interpretation in the spirit of type-naturalism. Consequently, its acceptance reveals both metaethical and anthropological allegations to which Strawson’s concept is exposed, without injuring the main part of his compatibilism.
Go to article

Abstract

The paper presents a concept of a control system for a high-frequency three-phase PWM grid-tied converter (3x400 V / 50 Hz) that performs functions of a 10-kW DC power supply with voltage range of 600÷800 V and of a reactive power compensator. Simulation tests (in PLECS) allowed proper selection of semiconductor switches between fast IGBTs and silicon carbide MOSFETs. As the main criterion minimum amount of power losses in semiconductor devices was adopted. Switching frequency of at least 40 kHz was used with the aim of minimizing size of passive filters (chokes, capacitors) both on the AC side and on the DC side. Simulation results have been confirmed in experimental studies of the PWM converter, the power factor of which (inductive and capacitive) could be regulated in range from 0.7 to 1.0 with THDi of line currents below 5% and energy efficiency of approximately 98.5%. The control system was implemented in Texas Instruments TMS320F28377S microcontroller.
Go to article

This page uses 'cookies'. Learn more