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Article
Publication date: 3 May 2013

Gheorghe Grigoras and Gheorghe Cartina

The purpose of this paper is to introduce a method based on the fuzzy correlation for modelling of active and reactive powers from the substations of the electrical…

Abstract

Purpose

The purpose of this paper is to introduce a method based on the fuzzy correlation for modelling of active and reactive powers from the substations of the electrical distribution systems, at the peak load.

Design/methodology/approach

Based on the correlation theory, the fuzzy models of the loads can be obtained using a new algorithm. If in the case of the principal/connection station there is sufficient database information for a good forecasting of the load, then for those substations where data are missing (there is no continuous monitoring or the measuring system can be broken for a while) the forecasting of the load can be performed using the correlation studies. The starting point of the algorithm is statistical analysis of the active and reactive curves of the substations and utilization of a fuzzy linear regression model. This can be made for different time windows (window 24 h, window 7 h, etc). The window 24 h can be used successfully to estimate the hourly load on any substation. The other time window (7 h) can be used in the peak load estimation of the substations, using the maximum value of the active power recorded in a reference substation.

Findings

The numerical data show that the fuzzy correlation models can be used with very good results for determination of the peak load corresponding distribution substations, and further with the state estimation of the system. In this study, the influence of the time window size is presented in detail, and the fuzzy correlation models for the peak loads from the distribution substations are obtained.

Originality/value

Starting from the correlation theory, a method of fuzzy modelling of active and reactive powers from the substations of an electrical distribution system is proposed.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 32 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

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Article
Publication date: 1 November 1944

W. Zalewski

THE speed at which a valve is coming to rest on its scat at the moment of closing is one of the factors deciding the amount of gases passed through the valve. The inertia…

Abstract

THE speed at which a valve is coming to rest on its scat at the moment of closing is one of the factors deciding the amount of gases passed through the valve. The inertia forces, however, act for a very short time on the valve at this moment, and this is the reason why normal considerations in the strength of valves are not accurate; it would be better, when designing the valve, to use approximate calculations giving the possibility of orientation among the various factors coming into consideration, than to leave all this to experimental practice.

Details

Aircraft Engineering and Aerospace Technology, vol. 16 no. 11
Type: Research Article
ISSN: 0002-2667

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Abstract

Details

Advances in Librarianship
Type: Book
ISBN: 978-0-12024-615-1

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Article
Publication date: 5 June 2017

Mohamed Yacine Debili, Nacira Sassane and Noureddine Boukhris

This paper aims to investigate ternary Al-Co-Ti alloy system with various Co compositions. Structural characterization of AlxCoy-2Ti2 alloys were performed by means of…

Abstract

Purpose

This paper aims to investigate ternary Al-Co-Ti alloy system with various Co compositions. Structural characterization of AlxCoy-2Ti2 alloys were performed by means of light microscopy, scanning electron microscopy, X-ray diffraction and electrochemical test. The effect of the addition of 5, 10, 15, 20, 25, 30 per cent Co and 2 per cent Ti on the structural evolution shows that both intermetallic compounds formation and structure morphology are related to corrosion resistance at the as-elaborated state as after subsequent heat treatment at 500°C during short time. According to the microstructural characterizations, the authors can notice that the substitution of Co has an important effect on the corrosion resistance and plays a role for the formation of the passive film.

Design/methodology/approach

The alloys in this study were obtained by a high-frequency induction fusion. Powders from Al, Co and Ti (99.999 per cent) in proportions defined according to the composition aimed of alloy have been used. The total mass of the sample to be elaborated lies between 8 and 10 g. Cold compaction was achieved for mixed powder intended for high fusion frequency (HF). For electrochemical tests, the sample was cut by a diamond wheel to obtain a square section of dimensions 1 cm2. Afterward, this sample was connected with a Cu electrical wire. The last stage is the envelope in an acrylic resin realized in a plastic mold. The used electrolyte is a salt environment of 3.5 per cent NaCl (35 g of NaCl by liter of distilled water at room temperature [25 ± 1°C], aerated and with moderated agitation V = 250 r.min−1). This mold is kept in ambient air for 10 min to allow the resin to solidify.

Findings

The aim of this work is to establish the influence of the addition of Co and Ti on structural change and related corrosion behavior improvement in Al. Particular attention is accorded to Al-15 per cent Co-2 per cent Ti alloy.

Originality/value

Among the studied alloys with different Co contents, a precise composition of 15 per cent Co and 2 per cent Ti appears to have interesting electrochemical characteristics regarding the corrosion potential, the corrosion current and particularly the corrosion rate, which is very small when compared to that of other alloys, as well in the as-solidified state than after heat treatment. This composition is located halfway between the stainless steel 304 and the Al-Fe and Al-Co-Ce alloys.

Details

Anti-Corrosion Methods and Materials, vol. 64 no. 4
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 3 January 2017

Natalia Ratajczyk, Iwona Wagner, Agnieszka Wolanska-Kaminska, Tomasz Jurczak and Maciej Zalewski

The purpose of this paper is to present the varied roles played by the University of Lódz (UL) in maintaining and restoring the natural capital of a city as a driver for…

Abstract

Purpose

The purpose of this paper is to present the varied roles played by the University of Lódz (UL) in maintaining and restoring the natural capital of a city as a driver for sustainable city development. The higher education institution can be perceived as visionary, originator and executor of natural capital projects.

Design/methodology/approach

The paper analyses three cases performed by the Faculty of Biology and Environmental Protection, UL, in the city of Lódz. The activities are based on different scales ranging from city-wide to local, e.g. river and green infrastructure, and which vary in character from policy planning to implementation.

Findings

Natural capital projects influence city development on different levels: by the initiation of legal protection, by the implementation of rehabilitation concepts for rivers and by influencing the strategic documents for mid-term and long-term urban development.

Originality/value

The university has the potential for multidisciplinary engagement in the development of urban sustainability. In large-scale projects, academics play a more conceptual role, in capacity building and knowledge transfer, while in local-scale implementations, their role includes innovation, know-how and technology transfer. Moreover, it may act as a reinforcement hub, by safeguarding and strengthening the natural capital of the city.

Details

International Journal of Sustainability in Higher Education, vol. 18 no. 1
Type: Research Article
ISSN: 1467-6370

Keywords

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Article
Publication date: 12 February 2019

Istefani Carisio de Paula, Elaine Aparecida Regiani de Campos, Regina Negri Pagani, Patricia Guarnieri and Mohammad Amin Kaviani

The purpose in this paper is to develop a systematic literature review aiming to reveal innovation opportunities associated with the thematic collaboration and trust in…

Abstract

Purpose

The purpose in this paper is to develop a systematic literature review aiming to reveal innovation opportunities associated with the thematic collaboration and trust in the reverse logistics field.

Design/methodology/approach

The authors adopted a parallel analysis approach segregating the systematic literature review papers in two groups at NVivo®, collaboration and trust in the supply chain and collaboration and trust in reverse logistics, aiming to explore in the first group of papers insights for innovation on collaboration and trust in reverse logistics. The content analysis strategy was supported by the knowledge exchange theory described in Gravier et al. (2008).

Findings

Reverse logistics is hardly dissociated from broader sustainable supply chain management approaches, which make all considerations on collaboration and trust designed for such approaches valuable and valid for reverse logistics. Collaboration and trust concepts in supply chain and in reverse logistics contexts are quite similar, while collaboration/trust is mandatory for managing networks in sustainable approaches and in reverse logistics, as well. Downstream and upstream, the chain disruptive innovation business models may be developed between focal companies and returns system third-party logistics providers, fourth-party logistics providers or end-customers, in a business-to-customer collaboration approach. Several collaboration technologies are listed in three perspectives: knowledge sharing, knowledge generation and knowledge implementation.

Research limitations/implications

This study uses a specific protocol for the systematic literature review, and due to inclusion and exclusion criteria, other protocols can provide different results. The strategy of analysis under the knowledge exchange perspective may give a type of result different from other perspectives.

Originality/value

This research systematizes the existing knowledge on the collaborations and trust, which is a priority basis for reverse logistics, providing insights to researchers and practitioners in the area and identifying an agenda for future studies.

Details

Supply Chain Management: An International Journal, vol. 25 no. 2
Type: Research Article
ISSN: 1359-8546

Keywords

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Article
Publication date: 2 January 2019

Wienczyslaw Stalewski and Wieslaw Zalewski

The purpose of this paper is to determine dependencies between a rotor-blade shape and a rotor performance as well as to search for optimal shapes of blades dedicated for…

Abstract

Purpose

The purpose of this paper is to determine dependencies between a rotor-blade shape and a rotor performance as well as to search for optimal shapes of blades dedicated for helicopter main and tail rotors.

Design/methodology/approach

The research is conducted based on computational methodology, using the parametric-design approach. The developed parametric model takes into account several typical blade-shape parameters. The rotor aerodynamic characteristics are evaluated using the unsteady Reynolds-averaged Navier–Stokes solver. Flow effects caused by rotating blades are modelled based on both simplified approach and truly 3D simulations.

Findings

The computational studies have shown that the helicopter-rotor performance may be significantly improved even through relatively simple aerodynamic redesigning of its blades. The research results confirm high potential of the developed methodology of rotor-blade optimisation. Developed families of helicopter-rotor-blade airfoils are competitive compared to the best airfoils cited in literature. The finally designed rotors, compared to the baselines, for the same driving power, are characterised by 5 and 32% higher thrust, in case of main and tail rotor, respectively.

Practical implications

The developed and implemented methodology of parametric design and optimisation of helicopter-rotor blades may be used in future studies on performance improvement of rotorcraft rotors. Some of presented results concern the redesigning of main and tail rotors of existing helicopters. These results may be used directly in modernisation processes of these helicopters.

Originality/value

The presented study is original in relation to the developed methodology of optimisation of helicopter-rotor blades, families of modern helicopter airfoils and innovative solutions in rotor-blade-design area.

Details

Aircraft Engineering and Aerospace Technology, vol. 91 no. 5
Type: Research Article
ISSN: 1748-8842

Keywords

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Book part
Publication date: 17 September 2014

Frédéric Zalewski

This chapter deals with the progressive political mobilisation of peasantry in Poland, its institutionalisation, mainly in inter-war period, and its political…

Abstract

This chapter deals with the progressive political mobilisation of peasantry in Poland, its institutionalisation, mainly in inter-war period, and its political appropriation by the Communist regime after 1945, when State socialism needed to ground itself in Polish national history and political traditions. These various mobilisations could be labelled as ‘populist’ because of their peasantist components and ideological trends, but the chapter considers them rather as a political form of representation, which political uses by actors fluctuate according historical contexts. The first part analyses the emergence of peasant movement and the success of peasant political parties in pre-1939 Poland. The second part shows how formers activists of these parties tried to produce themselves as the only historical heirs of the peasant movement, in opposition to the new, Leninist, peasant party of the Communist Poland. In the third and last part, the chapter analyses how the Communist official peasant party, the ZSL, invented new political traditions, mainly by historicising strategies, in the aim to encapsulate the peasant form of representation in its identity.

Details

The Many Faces of Populism: Current Perspectives
Type: Book
ISBN: 978-1-78350-258-5

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Article
Publication date: 19 July 2019

Sandra L. Furterer, Kellie Schneider, Michael B. Key, Daniel Zalewski and Michael Laudenberger

The purpose of this study is to improve the utilization of walk-in tutors at the University of Dayton.

Abstract

Purpose

The purpose of this study is to improve the utilization of walk-in tutors at the University of Dayton.

Design/methodology/approach

This paper discusses the application of mixed methods participatory action research with the use of the lean six sigma (LSS) define-measure-analyze-improve-control (DMAIC) methodology combined with discrete event simulation to improve the tutoring processes at the University of Dayton.

Findings

The impact of these improvements provided a great balance between tutor utilization and student wait time, and as a result, an increase in pay was negotiated for tutors. Additionally, two schools within the University, Engineering and Business, have seen the value of the tutoring for their students and have provided additional financial support for tutoring services. Specifically, these schools now have dedicated by-appointment tutors for their students.

Originality/value

Incorporating simulation within the LSS methodology provides a “prototype” simulation of the potential solutions prior to changing the process in the real world. This approach can minimize the risk of implementing solutions that are costly or ineffective. The improvement of increased tutor pay helped to demonstrate the university’s commitment to tutors and tutoring. Through continuous improvement efforts, the tutoring department has tripled the number of courses that they support through these enhanced relationships, improved utilization and the overall culture and work environment. The LSS methodology and tools combined with discrete event simulation can be used as a guide for improving other repetitive processes within the university.

Details

International Journal of Lean Six Sigma, vol. 10 no. 4
Type: Research Article
ISSN: 2040-4166

Keywords

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Book part
Publication date: 26 August 2019

Ranjit S. Dighe

The editorials of the then-new Business Week during the 1929–1933 contraction offered sophisticated Keynesian policy prescriptions: against a laissez-faire response…

Abstract

The editorials of the then-new Business Week during the 1929–1933 contraction offered sophisticated Keynesian policy prescriptions: against a laissez-faire response, against deflation, against balanced-budget fetishism, for monetary expansion. These editorials, which seem to have been largely forgotten, likely played a considerable role in the dissemination of Keynesian economics in the United States in the 1930s. This chapter reviews the editorials and their congruence with Keynes’s writings. The magazine’s archives, including surveys of their readers, suggest that the editorials were among the most read and most valued parts of the magazine. The magazine cultivated an elite executive readership at that time, so the editorials may well have been important in gaining business support for Keynesian policies in the early New Deal.

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