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Article
Publication date: 1 April 2008

O. Pozo, B. Soulestin and N. Olivi‐Tran

We set up an original apparatus to measure the grain grain friction stress inside a granular medium composed of sodo‐silicate‐glass beads surrounded by a water vapor atmosphere.We…

119

Abstract

We set up an original apparatus to measure the grain grain friction stress inside a granular medium composed of sodo‐silicate‐glass beads surrounded by a water vapor atmosphere.We analyze here the influence of the physico chemistry of water on our glass beads and its consequences on our shear experiment. We found two scales in the analysis of the shear stress signal. On the microscopic scale of one bead, the experimental results show a dependence on the size of beads, on the shear rate and on humidity for the resulting stick slip signal. On the macroscopic scale of the whole assembly of beads, the behavior of the total amplitude of the shear stress depends on the size of the beads and is humidity dependent only for relative humidity larger than 80%. For high degrees of humidity, on the microscopic scale, water lubricates the surface of the beads leading to a decrease in the microscopic resistance to shear while on the macroscopic scale the resistance to shear is increased: the assembly of very humid grains behaves as a rheothickening fluid.

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Multidiscipline Modeling in Materials and Structures, vol. 4 no. 4
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 1 February 2008

O. Pozo1and and N. Olivi‐Tran

A Molecular Dynamics approach has been used to compute the shear force resulting from the shearing of disks. Two‐dimensional mono‐disperse disks have been put in an horizontal and…

98

Abstract

A Molecular Dynamics approach has been used to compute the shear force resulting from the shearing of disks. Two‐dimensional mono‐disperse disks have been put in an horizontal and rectangular shearing cell with periodic boundary conditions on right and left hand sides. The shear is applied by pulling the cover of the cell either at a constant rate or by pulling a spring, linked to the cover, with a constant force. Depending on the rate of shearing and on the elasticity of the whole set‐up, we showed that the measured shear force signal is either irregular in time, regular in time but not in shape, or regular in shape.

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Multidiscipline Modeling in Materials and Structures, vol. 4 no. 2
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 11 October 2022

Marina Stramarkou, Achilleas Bardakas, Magdalini Krokida and Christos Tsamis

Carbon dioxide (CO2) has attracted special scientific interest over the last years mainly because of its relation to climate change and indoor air quality. Except for this, CO2

350

Abstract

Purpose

Carbon dioxide (CO2) has attracted special scientific interest over the last years mainly because of its relation to climate change and indoor air quality. Except for this, CO2 can be used as an indicator of food freshness, patients’ clinical state and fire detection. Therefore, the accurate monitoring and controlling of CO2 levels are imperative. The development of highly sensitive, selective and reliable sensors that can efficiently distinguish CO2 in various conditions of temperature, humidity and other gases’ interference is the subject of intensive research with chemi-resistive zinc oxide (ZnO)-based sensors holding a privileged position. Several ZnO nanostructures have been used in sensing applications because of their versatile features. However, the deficient selectivity and long-term stability remain major concerns, especially when operating at room temperature. This study aims to encompass an extensive study of CO2 chemi-resistive sensors based on ZnO, introducing the most significant advances of recent years and the best strategies for enhancing ZnO sensing properties.

Design/methodology/approach

An overview of the different ZnO nanostructures used for CO2 sensing and their synthesis methods is presented, focusing on the parameters that highly affect the sensing mechanism and, thus, the performance of CO2 sensors.

Findings

The selectivity and sensitivity of ZnO sensors can be enhanced by adjusting various parameters during their synthesis and by doping or treating ZnO with suitable materials.

Originality/value

This paper summarises the advances in the rapidly evolving field of CO2 sensing by ZnO sensors and provides research directions for optimised sensors in the future.

Details

Sensor Review, vol. 42 no. 6
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 8 August 2016

Andrea G Capodaglio, Arianna Callegari and Daniele Molognoni

Advancements in real-time water monitoring technologies permit rapid detection of water quality, and threats from waste loads. Water Framework Directive mandating the…

959

Abstract

Purpose

Advancements in real-time water monitoring technologies permit rapid detection of water quality, and threats from waste loads. Water Framework Directive mandating the establishment of Member States’ water resources monitoring, presence of hazardous contaminants in effluents, and perception of vulnerability of water distribution system to attacks, have spurred technical and economic interests. The paper aims to discuss these issues.

Design/methodology/approach

As alternative to traditional analyzers, chemosensors, operate according to physical principles, without sample collection (online), and are capable of supplying parameter values continuously and in real-time. Their low selectivity and stability issues have been overcome by technological developments. This review paper contains a comprehensive survey of existing and expected online monitoring technologies for measurement/detection of pollutants in water.

Findings

The state-of-the-art in online water monitoring is presented. Application examples are reported. Monitoring costs will become a lesser part of a water utility budget due to the fact that automation and technological simplification will abate human cost factors, and reduce the complexity of laboratory procedures.

Originality/value

An overview of applicable instrumentation, and forthcoming developments, is given. Technological development in this field is very rapid, and astonishing advances are anticipated in several areas (fingerprinting, optochemical sensors, biosensors, molecular techniques). Online monitoring is becoming an ever-important tool not only for compliance control or plant management purposes, but also as a useful approach to pollution control and reduction, minimizing the environmental impact of discharges.

Details

Management of Environmental Quality: An International Journal, vol. 27 no. 5
Type: Research Article
ISSN: 1477-7835

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Article
Publication date: 23 July 2021

Evangelos Psomas

Many future research proposals of Lean Manufacturing (LM) are presented in the literature. The purpose of this paper is to determine these future research proposals of LM which…

584

Abstract

Purpose

Many future research proposals of Lean Manufacturing (LM) are presented in the literature. The purpose of this paper is to determine these future research proposals of LM which are country-related and classify them.

Design/methodology/approach

A systematic literature review (SLR) of peer-reviewed journal articles in LM was conducted. A total of 145 articles published in 34 journals during 2010–2020 were collected from four major management science publishers namely, Emerald Online, Elsevier/Science Direct, Springer Link and Taylor and Francis. The country-related future research proposals of LM identified in the literature were classified according to, firstly, the continent of the country of reference, and secondly, some form of natural affinity of these proposals creating meaningful themes. The quality tool “affinity diagram” was applied to classify the country-related future research proposals of LM.

Findings

The country-related future research proposals of LM, which are increasing in the literature over time, refer mostly to studies to be conducted in several continents/countries and to multinational studies. Conducting studies specifically in Asia, Europe, South and North America, Africa and Australia–New Zealand is also suggested. The plethora of the country-related future research proposals of LM were classified, based on the affinity of their content, into 18 meaningful themes. These themes were also classified based on their affinity into two broad categories, namely “themes concerning the LM approach itself” and “themes concerning factors outside the LM approach”.

Research limitations/implications

The restricted number of the databases searched and the subjectivity of classifying the large number of the country-related future research proposals into themes are the main limitations of the present SLR. Based on these limitations, future literature review studies can be carried out.

Practical implications

Useful proposals are provided to researchers of several countries for conducting original and country-specific research studies which can enrich the knowledge of the implementation of LM under the specific circumstances of a country for the benefit of practitioners.

Originality/value

This study goes beyond previous literature review studies on LM by focusing exclusively on the LM future research agenda which is country related. The analytical presentation of the country-related future research proposals as well as the formulation of clusters of these proposals make the present SLR study substantially different from those carried out worldwide so far.

Details

Benchmarking: An International Journal, vol. 29 no. 4
Type: Research Article
ISSN: 1463-5771

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Article
Publication date: 9 September 2013

Yap Wing Fen and W. Mahmood Mat Yunus

The purpose of this paper is to review the novel application of surface plasmon resonance (SPR) in sensing heavy metal ions and the development of SPR to become an alternative…

1154

Abstract

Purpose

The purpose of this paper is to review the novel application of surface plasmon resonance (SPR) in sensing heavy metal ions and the development of SPR to become an alternative heavy metal ions sensor.

Design/methodology/approach

The possible dangerous toxic effects of heavy metal ions are revealed in the short introduction. The existing conventional methods for sensing heavy metal ions and their drawbacks are also discussed. To overcome these drawbacks, SPR has been investigated from the basic principle to the potential alternative in sensing heavy metal ions.

Findings

Application of SPR in sensing heavy metal ions emerged a decade ago. A wide range of active layers or recognition elements (e.g. polymer, protein, nanoparticles) have been developed to combine with SPR. The detection limit, sensitivity and selectivity of SPR sensing in heavy metal ions have been improved from time to time, until the present.

Originality/value

This paper provides up-to-date and systematic information on SPR sensing for heavy metal ions. Different advancements on active layers or recognition molecules have been discussed in detail and arranged in the order of their chronological evolution. The present review may provide researchers with valuable information regarding novel heavy metal ions sensor using SPR and encourage them to take this area for further research and development.

Details

Sensor Review, vol. 33 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

Available. Open Access. Open Access
Article
Publication date: 1 November 2023

Elena Lasso-Dela-Vega, José Luis Sánchez-Ollero and Alejandro García-Pozo

This study conducts a comparative analysis of the impact of educational mismatch on Spanish wages. This paper aims to focus on the industrial, construction and service sectors at…

924

Abstract

Purpose

This study conducts a comparative analysis of the impact of educational mismatch on Spanish wages. This paper aims to focus on the industrial, construction and service sectors at three levels of disaggregation: sector, occupation and gender.

Design/methodology/approach

The over-education, required education and under-education (ORU model), was applied to data from the 2018 Spanish Wages Structure Survey conducted by the Spanish National Statistics Institute.

Findings

The industrial sector is the one that best manages over-education by offering the highest returns to each year of over-education. It is also the sector that most values the education of women, particularly those in highly qualified positions.

Originality/value

This study compares the wage effects of educational mismatch in the service, industry and construction sectors. Previous literature has ignored the latter sectors in this field of study, but the results of the present study show that the industrial sectors significantly value and remunerates worker education. Therefore, it may be worthy to focus certain economic and social policies on this sector, to contribute to reducing gender wage gaps and gender employment discrimination in the economy.

Details

International Journal of Manpower, vol. 44 no. 9
Type: Research Article
ISSN: 0143-7720

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Book part
Publication date: 24 February 2023

Sarahit Castillo-Benancio, Aldo Alvarez-Risco, Flavio Morales-Ríos, Maria de las Mercedes Anderson-Seminario and Shyla Del-Aguila-Arcentales

In a pandemic framework (COVID-19), this chapter explores the impact of the global economy and socio-cultures concerning three axes: recreational, tourism, and hospitality…

Abstract

In a pandemic framework (COVID-19), this chapter explores the impact of the global economy and socio-cultures concerning three axes: recreational, tourism, and hospitality. Although we slowly see an economic revival, it is well known that this sector of study is very susceptible to being affected by the context of nations. Following restrictions and measures taken by governments around the world to reduce the number of cases of coronavirus infections, many nations closed their borders, affecting international travel and by 2020 tourism had been reduced to the near cessation of operations due to the imminent fear of this poorly studied disease, and the service sector was negatively affected. It should be added that, according to the World Tourism Organization's projections, a decrease of between 20 and 30% is forecast for 2020 compared to the previous year.

Details

Sustainable Management in COVID-19 Times
Type: Book
ISBN: 978-1-80382-597-7

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Article
Publication date: 25 July 2024

Ibnu Qizam, Najwa Khairina and Novita Betriasinta

The purpose of this study is to investigate and compare the dynamic leverage policies of Islamic and conventional banks within selected Organization of Islamic Cooperation (OIC…

213

Abstract

Purpose

The purpose of this study is to investigate and compare the dynamic leverage policies of Islamic and conventional banks within selected Organization of Islamic Cooperation (OIC) countries. The study specifically focuses on the concepts of leverage procyclicality and prospect theory.

Design/methodology/approach

To achieve the research objectives, the study uses data from three distinct periods: Crisis I (2007–2009), Crisis II (2011–2012) and Crisis III (2020). The analysis uses dynamic panel-data regression, using the generalized method of moments (GMM) technique.

Findings

The research findings indicate that both Islamic and conventional banks demonstrate leverage procyclicality. Interestingly, Islamic banks exhibit weaker leverage procyclicality during normal conditions but display stronger procyclicality during crises compared to their conventional counterparts. The application of prospect theory reveals that both bank types exhibit risk-taking or risk-averse behavior through leverage under certain financial and market performance measures as the first-level domain of the gain-vs-loss condition. Furthermore, during crises (as the second-level domain of the normal-vs-crisis condition), both Islamic and conventional banks experience heightened leverage. Notably, Islamic banks, owing to their lower risk exposure and greater shock resilience, demonstrate lesser risk-taking behavior through leverage than conventional banks, both during periods of underperformance and worsening conditions amid crises. These findings validate the extension of prospect theory's applicability in a two-level domain perspective. The dynamic nature of leverage policy, being procyclical and adhering to prospect theory, also varies following different crises specifically.

Research limitations/implications

The study's limitations include the unequal crisis periods (Crises I, II and III), leading to an imbalanced examination of their effects, certain financial and market performance metrics that fail to corroborate the expected hypotheses and the limited generalizability of findings beyond the selected OIC countries.

Practical implications

Understanding the intricate dynamics and behavioral aspects of leverage policy for both Islamic and conventional banks, particularly during crisis scenarios, proves crucial for reviewing banking regulations, making informed financial decisions and managing risks effectively.

Originality/value

This study enriches the current knowledge by presenting two key points. First, it highlights the dynamic nature of leverage procyclicality in Islamic banks, showing a change from weaker procyclicality in normal conditions to stronger procyclicality during crises compared to conventional banks. Second, it expands the application of prospect theory by introducing a dual-level domain context. Examining the comparative leverage policies of Islamic and conventional banks during different crises within OIC countries provides novel insights into leverage procyclicality and behavioral responses.

Details

Journal of Islamic Accounting and Business Research, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1759-0817

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Article
Publication date: 10 June 2021

Abhijat Arun Abhyankar and Harish Kumar Singla

The purpose of this study is to compare the predictive performance of the hedonic multivariate regression model with the probabilistic neural network (PNN)-based general…

362

Abstract

Purpose

The purpose of this study is to compare the predictive performance of the hedonic multivariate regression model with the probabilistic neural network (PNN)-based general regression neural network (GRNN) model of housing prices in “Pune-India.”

Design/methodology/approach

Data on 211 properties across “Pune city-India” is collected. The price per square feet is considered as a dependent variable whereas distances from important landmarks such as railway station, fort, university, airport, hospital, temple, parks, solid waste site and stadium are considered as independent variables along with a dummy for amenities. The data is analyzed using a hedonic type multivariate regression model and GRNN. The GRNN divides the entire data set into two sets, namely, training set and testing set and establishes a functional relationship between the dependent and target variables based on the probability density function of the training data (Alomair and Garrouch, 2016).

Findings

While comparing the performance of the hedonic multivariate regression model and PNN-based GRNN, the study finds that the output variable (i.e. price) has been accurately predicted by the GRNN model. All the 42 observations of the testing set are correctly classified giving an accuracy rate of 100%. According to Cortez (2015), a value close to 100% indicates that the model can correctly classify the test data set. Further, the root mean square error (RMSE) value for the final testing for the GRNN model is 0.089 compared to 0.146 for the hedonic multivariate regression model. A lesser value of RMSE indicates that the model contains smaller errors and is a better fit. Therefore, it is concluded that GRNN is a better model to predict the housing price functions. The distance from the solid waste site has the highest degree of variable senstivity impact on the housing prices (22.59%) followed by distance from university (17.78%) and fort (17.73%).

Research limitations/implications

The study being a “case” is restricted to a particular geographic location hence, the findings of the study cannot be generalized. Further, as the objective of the study is restricted to just to compare the predictive performance of two models, it is felt appropriate to restrict the scope of work by focusing only on “location specific hedonic factors,” as determinants of housing prices.

Practical implications

The study opens up a new dimension for scholars working in the field of housing prices/valuation. Authors do not rule out the use of traditional statistical techniques such as ordinary least square regression but strongly recommend that it is high time scholars use advanced statistical methods to develop the domain. The application of GRNN, artificial intelligence or other techniques such as auto regressive integrated moving average and vector auto regression modeling helps analyze the data in a much more sophisticated manner and help come up with more robust and conclusive evidence.

Originality/value

To the best of the author’s knowledge, it is the first case study that compares the predictive performance of the hedonic multivariate regression model with the PNN-based GRNN model for housing prices in India.

Details

International Journal of Housing Markets and Analysis, vol. 15 no. 2
Type: Research Article
ISSN: 1753-8270

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