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Article
Publication date: 21 December 2021

Saranya P., Praveen Nagarajan and A.P. Shashikala

This study aims to predict the fracture properties of geopolymer concrete, which is necessary for studying failure behaviour of concrete.

Abstract

Purpose

This study aims to predict the fracture properties of geopolymer concrete, which is necessary for studying failure behaviour of concrete.

Design/methodology/approach

Geopolymers are new alternative binders for cement in which polymerization gives strength to concrete rather than through hydration. Geopolymer concrete was developed from industrial byproducts such as GGBS and dolomite. Present study estimates the fracture energy of GGBS geopolymer concrete using three point bending test (RILEM TC50-FMC) with different percentages of dolomite and compare with cement concrete having same strength.

Findings

The fracture properties such as peak load, critical stress intensity factor, fracture energy and characteristic length are found to be higher for GGBS-dolomite geopolymer concrete, when their proportion becomes 70:30.

Originality/value

To the best of the authors’ knowledge, this is an original experimental work.

Details

Journal of Engineering, Design and Technology , vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1726-0531

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Article
Publication date: 5 September 2016

Krzysztof Olasek, Maciej Karczewski, Michal Lipian, Piotr Wiklak and Krzysztof Józwik

A solution to increase the energy production rate of the wind turbine is proposed by forcing more air to move through the turbine working section. This can be achieved by…

Abstract

Purpose

A solution to increase the energy production rate of the wind turbine is proposed by forcing more air to move through the turbine working section. This can be achieved by equipping the rotor with a diffusing channel ended with a brim (diffuser augmented wind turbine – DAWT). The purpose of this paper is to design an experimental stand and perform the measurements of velocity vector fields through the diffuser and power characteristic of the wind turbine.

Design/methodology/approach

The experiments were carried out in a small subsonic wind tunnel at the Institute of Turbomachinery, Lodz University of Technology. An experimental stand design process as well as measurement results are presented. Model size sensitivity study was performed at the beginning. The experimental campaign consisted of velocity measurements by means of particle image velocimetry (PIV) and pneumatic pitot probe as well as torque and rotational velocity measurements.

Findings

Characteristics (power coefficient vs tip speed ratio) of the bare and shrouded wind turbine were obtained. The results show an increase in the wind turbine power up to 70-75 per cent by shrouding the rotor with a diffuser. The mechanisms responsible for such a power increase were well explained by the PIV and pneumatic measurement results revealing the nature of the flow through the diffuser.

Research limitations/implications

Experimental stand for wind turbine rotor testing is of a preliminary character. Most optimal methodology for obtaining power characteristic should be determined now. Presented results can serve as good input for choice of stable and reliable control system of wind turbine operational parameters.

Practical implications

A 3 kW DAWT is being developed at the Institute of Turbomachinery, Lodz University of Technology. Aim of the study is to design a compact and smart wind turbine optimised for low wind speed conditions. Developed wind turbine has a potential to be used as an effective element within a net of distributed generation, e.g. for domestic use.

Originality/value

Research carried out is the continuation of theoretical study began in 1970s. It was also inspired by practical solutions proposed by Japanese researchers few years ago. Presented paper is the summary of work devoted to optimisation of the DAWT for wind conditions in the region. Original solution has been applied, e.g. for experimental stand design (3D printing application).

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 26 no. 7
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 2 January 2009

Wenjie Shiu, Frédéric Victor Donzé and Laurent Daudeville

The purpose of this paper is to describe how a discrete element model is used to predict the penetration depth and the perforation caused by a non‐deformable missile…

Abstract

Purpose

The purpose of this paper is to describe how a discrete element model is used to predict the penetration depth and the perforation caused by a non‐deformable missile against a thin reinforced concrete slab.

Design/methodology/approach

Initial calibration of the model was done with a series of flat‐nose missile tests. Additional simulations were performed with varying the percentage of reinforcement. The present numerical model is compared to experimental test data provided by the French Atomic Energy Agency (CEA) and the French Electrical Power Company (EDF).

Findings

For thin concrete slabs, the evolution of the penetration depth in terms of percentage of reinforcement was compared with experimental results: quantitatively the results are very coherent.

Originality/value

The modeling scale is higher than the heterogeneity scale, so the model may be used to simulate real structures, which means that the discrete element method is mainly used here for its ability to account for discontinuities; an identification process based on quasi‐static tests is used, so the quasi‐static behavior of concrete is reproduced. This identification process is the key point, to allow a complete predictive computation for complex impact configurations, especially when the missile diameter and the thickness of the concrete slab are on the same order in size.

Details

Engineering Computations, vol. 26 no. 1/2
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 September 1951

K.G. Wilkinson

A sailplane designer will normally base a new design on his experience of the relative success of various earlier types in competitive flying and will be guided by a few…

Abstract

A sailplane designer will normally base a new design on his experience of the relative success of various earlier types in competitive flying and will be guided by a few simple performance criteria such as minimum sinking speed, glide ratio and the less precisely defined property of ‘penetration’ (this being, roughly, the ability to achieve a good glide ratio at a high forward speed). This empirical approach has resulted in the evolution of an aerodynamic form of considerable efficiency. It is not easy, however, to see precisely why the present form has proved so effective or what potential development lies ahead. One reason for this is that none of the criteria mentioned is an absolute index of efficiency nor does it represent the range of operations that a sailplane is called upon to cover in practice. A clearer insight demands a deeper analysis of the basic requirements for sailplane performance, to see whether a more effective index of efficiency can be found. Such an index is developed in this paper and the effectiveness of varying the main design parameters is examined with its aid.

Details

Aircraft Engineering and Aerospace Technology, vol. 23 no. 9
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 January 1995

Marilyn E. Barnes

Libraries need to develop information processing systems for evaluation, budgeting, planning, and operations. Electronic spreadsheets lend themselves to a variety of…

Abstract

Libraries need to develop information processing systems for evaluation, budgeting, planning, and operations. Electronic spreadsheets lend themselves to a variety of applications, but are time‐consuming to create. A model template and macros that can be used in many different types of library data analysis have been developed here. The procedures demonstrated here can build an essential set of tools for meeting fundamental goals of administrative efficiency, effective use of library resources, staff motivation, and rational policy making.

Details

The Bottom Line, vol. 8 no. 1
Type: Research Article
ISSN: 0888-045X

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Book part
Publication date: 10 October 2017

Gaston Yalonetzky

Relative bipolarisation indices are usually constructed making sure that they achieve their minimum value of bipolarisation if and only if distributions are perfectly…

Abstract

Relative bipolarisation indices are usually constructed making sure that they achieve their minimum value of bipolarisation if and only if distributions are perfectly egalitarian. However, the literature has neglected discussing the existence of a benchmark of maximum relative bipolarisation. Consequently there is no discussion as to the implications of maximum bipolarisation for the optimal normalisation of relative bipolarisation indices either. In this note we characterize the situation of maximum relative bipolarisation as the only one consistent with the key axioms of relative bipolarisation. We illustrate the usefulness of incorporating the concept of maximum relative bipolarisation in the design of bipolarisation indices by identifying, among the family of rank-dependent Wang–Tsui indices, the only subclass fulfilling a normalisation axiom that takes into account both benchmarks of minimum and maximum relative bipolarisation.

Details

Research on Economic Inequality
Type: Book
ISBN: 978-1-78714-521-4

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Book part
Publication date: 10 October 2017

Gaston Yalonetzky

The relative bipolarisation literature features examples of indices which depend on the median of the distribution, including the renowned Foster–Wolfson index. This study…

Abstract

The relative bipolarisation literature features examples of indices which depend on the median of the distribution, including the renowned Foster–Wolfson index. This study shows that the use of the median in the design and computation of relative bipolarisation indices is both unnecessary and problematic. It is unnecessary because we can rely on existing well-behaved, median-independent indices. It is problematic because, as the study shows, median-dependent indices violate the basic transfer axioms of bipolarisation (defining spread and clustering properties), except when the median is unaffected by the transfers. The convenience of discarding the median from index computations is further illustrated with a numerical example in which median-independent indices rank distributions according to the basic transfer axioms while median-dependent indices do not.

Details

Research on Economic Inequality
Type: Book
ISBN: 978-1-78714-521-4

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Book part
Publication date: 30 September 2014

Jürgen Faik and Uwe Fachinger

In the wake of the Stiglitz Commission, we assess German economic well-being by considering income, wealth and consumption. A decomposition approach is used to test for…

Abstract

In the wake of the Stiglitz Commission, we assess German economic well-being by considering income, wealth and consumption. A decomposition approach is used to test for corresponding inequality differences of these well-being dimensions. Total inequality is decomposed into within- and between-group inequality (via a normalised coefficient of variation). The decompositions are categorised into those that refer to socio-demographic characteristics (place of residence, age, household type) and those belonging to different well-being (sub-)categories (potential and net income, expenditure and wealth categories). The empirical analyses are performed for Germany using the 2008 German Sample Survey of Income and Expenditure. By decomposing German well-being inequality in great detail, we shed light on its dimensions. Our analyses illustrate that it is necessary to consider all well-being dimensions to make statements about the material well-being of private households or individuals.

Details

Economic Well-Being and Inequality: Papers from the Fifth ECINEQ Meeting
Type: Book
ISBN: 978-1-78350-556-2

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Article
Publication date: 20 May 2020

Martin B. Schmidt

Talent compression is the labor market phenomenon where the average productivity differential between participants declines and has been used to explain the overall…

Abstract

Purpose

Talent compression is the labor market phenomenon where the average productivity differential between participants declines and has been used to explain the overall increase in competition within some professional sports markets. A finding that competitiveness is uniquely driven by talent compression is consistent with Rottenberg (1956), who argued that resource distribution is independent of factors that are invariant to labor productivity.

Design/methodology/approach

Rather than incorporate MLB team roster turnover as many of the past studies have done, we prefer to measure of all-star turnover in membership. Problematically, movement from an MLB team to an MLB team is limited by rule, finances and the fact that there are very few teams competing for player services. In contrast, All-Star membership is typically costlessly chosen by many millions of fans, league players and managers. In this way, All-Star voting should be invariant to many of the factors that affect movement from an MLB team to an MLB team.

Findings

In the end, we find that a close association between all-star turnover rates and the makeup of MLB’s labor pool.

Originality/value

The paper offers a new measure of player mobility.

Details

Journal of Economic Studies, vol. 48 no. 1
Type: Research Article
ISSN: 0144-3585

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Article
Publication date: 10 October 2016

Madhu Sehrawat and A.K. Giri

The purpose of this paper is to examine the relationship between financial development and rural-urban income inequality (INQ) in South Asian Association for Regional…

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Abstract

Purpose

The purpose of this paper is to examine the relationship between financial development and rural-urban income inequality (INQ) in South Asian Association for Regional Cooperation (SAARC) countries using panel data from 1986-2012.

Design/methodology/approach

The stationarity properties are checked by the LLC and IPS panel unit root tests. The paper applied the Pedroni’s panel co-integration test to examine the existence of the long-run relationship and coefficients of co-integration are examined by fully modified ordinary least squares. The short-term and long-run causality is examined by panel Granger causality.

Findings

The results of Pedroni co-integration test indicate that there exists a long-run relationship among the variables. The findings suggest that financial development increases rural-urban inequality whereas trade openness reduces rural-urban inequality. The empirical results of panel Granger causality indicate evidence of short-run causality confirms that economic growth and financial development causes rural-urban INQ.

Research limitations/implications

The present study recommends for appropriate economic and financial reforms focusing on financial inclusion to reduce rural-urban INQ in SAARC countries. Financial policies geared toward agriculture and rural population should be adopted to reduce the prevailing rural-urban INQ in SAARC region.

Originality/value

Till date, there is hardly any study exploring the causal relationship between financial development and rural-urban INQ for SAARC countries by using panel co-integration and causality techniques. So the contribution of the paper is to fill these research gaps in the literature.

Details

International Journal of Social Economics, vol. 43 no. 10
Type: Research Article
ISSN: 0306-8293

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