Search results

1 – 10 of 10
Per page
102050
Citations:
Loading...
Access Restricted. View access options
Article
Publication date: 30 July 2019

Ahmed K. Abdelmoety, Taha H.A. Naga and Youssef F. Rashed

This paper aims to develop a new isogeometric boundary element formulation based on non-uniform rational basis splines (NURBS) curves for solving Reissner’s shear-deformable…

178

Abstract

Purpose

This paper aims to develop a new isogeometric boundary element formulation based on non-uniform rational basis splines (NURBS) curves for solving Reissner’s shear-deformable plates.

Design/methodology/approach

The generalized displacements and tractions along the problem boundary are approximated as NURBS curves having the same rational B-spline basis functions used to describe the geometrical boundary of the problem. The source points positions are determined over the problem boundary by the well-known Greville abscissae definition. The singular integrals are accurately evaluated using the singularity subtraction technique.

Findings

Numerical examples are solved to demonstrate the validity and the accuracy of the developed formulation.

Originality/value

This formulation is considered to preserve the exact geometry of the problem and to reduce or cancel mesh generation time by using NURBS curves employed in computer aided designs as a tool for isogeometric analysis. The present formulation extends such curves to be implemented as a stress analysis tool.

Details

Engineering Computations, vol. 37 no. 1
Type: Research Article
ISSN: 0264-4401

Keywords

Access Restricted. View access options
Article
Publication date: 29 March 2013

Ahmed M. Hussein and Youssef F. Rashed

This paper computationally estimates the constitutive relationships of composite materials reinforced by single walled carbon nanotubes (SWNT).

256

Abstract

Purpose

This paper computationally estimates the constitutive relationships of composite materials reinforced by single walled carbon nanotubes (SWNT).

Design/methodology/approach

A multiscale analysis is considered. At the nanoscale level, molecular dynamics (MD) are used to predict the stiffness for an equivalent beam. A BEM solver for the elasticity problems is extended to allow the presence of inclusions and hence is used to model a RVE for the composite matrix with the equivalent nanotube beams. A genetic algorithm (GA) is developed to generate an initial population of anisotropic materials based on FEM. The GA evolves the population of properties of anisotropic materials till a material is found whose mechanical response is the same as that of the nanocomposite.

Findings

The overall process is suitable for the constitutive relationships estimation according to the verification process outlined.

Research limitations/implications

The present work is limited to 2D linear problems. However, extending it to 3D non‐linear applications is straight forward.

Practical implications

The present technique could be used to estimate properties of NCT composites, hence practical applications such as aeroplane structures or turbine blades could be analysed using commercial finite element software. The present methodology could be used to estimate non‐mechanical properties such as the thermal and electric properties.

Originality/value

The present computational technique has never been presented in the literature.

Details

Engineering Computations, vol. 30 no. 3
Type: Research Article
ISSN: 0264-4401

Keywords

Access Restricted. View access options
Article
Publication date: 20 October 2020

Priyanka Sihag

The importance of psychological capital (PsyCap) and perceived organizational support (POS) have been identified over the years, however, the underlying relationship of both…

1468

Abstract

Purpose

The importance of psychological capital (PsyCap) and perceived organizational support (POS) have been identified over the years, however, the underlying relationship of both constructs with different employee outcomes is still a subject of research. The purpose of this study is to investigate whether POS helps in mediating the effect of PsyCap on employee engagement (EE).

Design/methodology/approach

In total, 420 samples (middle-level information technology (IT) professionals) were collected from different IT industry located in India by using online survey questionnaires. The collected data were further analyzed using regression analysis, factor analysis, structural equation modeling, reliability and validity analysis, mediation analysis and model fit indices analysis.

Findings

The results of the present study confirmed the full mediating effect of POS on the PsyCap-EE relationship and demonstrated that employees with a higher level of PsyCap, contribute more positively to the POS level which further enhances the employee’s level of engagement at the workplace.

Research limitations/implications

The samples collected for the current study included only middle-level IT professionals of the IT industry in India; therefore, the present study results have limited general applicability. The results and findings of the current study are only on the basis of inferential statistical analysis, and descriptive analysis was not performed on the collected data. Further, the study does not investigate the influence of time.

Practical implications

This study would assist practitioners of human resources in organizational development by enhancing the employee’s positive attitude and commitment toward their study. Further, EE can also be improved by enhancing the levels of POS and PsyCap of employees, which is in line with the findings of the current study.

Originality/value

The current study examines the mediating effect of POS on psychological capital and EE the relationship for the first time.

Details

Journal of Indian Business Research, vol. 13 no. 1
Type: Research Article
ISSN: 1755-4195

Keywords

Access Restricted. View access options
Article
Publication date: 27 September 2022

Gomaa Abdel-Maksoud, Aya Abdallah, Rana Youssef, Doha Elsayed, Nesreen Labib, Wael S. Mohamed and Medhat Ibrahim

This study aims to evaluate the efficiency of using some polymers at different concentrations in the consolidation of vegetable-tanned leather artifacts.

155

Abstract

Purpose

This study aims to evaluate the efficiency of using some polymers at different concentrations in the consolidation of vegetable-tanned leather artifacts.

Design/methodology/approach

New vegetable-tanned leather samples were prepared. The consolidants used were polyacrylamide (PAM) and polymethyl methacrylate/hydroxyethyl methacrylate (MMA-HEMA). Accelerated heat aging was applied to the untreated and treated samples. Analytical techniques used were Fourier transform infrared spectroscopy (FTIR), digital microscope, scanning electron microscope (SEM), change of color and mechanical properties.

Findings

The characteristic FTIR bands showed the effect of accelerated heat aging on the molecular structure of the studied samples, but treated and aged treated samples used were better than aged untreated samples. Microscopic investigations (digital and SEM), and mechanical properties proved that 2% was the best concentration for polymers used. The change in the total color difference of the treated and aged treated samples was limited.

Originality/value

This study presents the important results obtained from PAM and poly(MMA-HEMA) used for the consolidation of vegetable-tanned leather artifacts. The best results of the studied polymers can be applied directly to protect historical vegetable-tanned leathers.

Available. Open Access. Open Access
Article
Publication date: 27 July 2023

Aicha Gasmi, Marc Heran, Noureddine Elboughdiri, Lioua Kolsi, Djamel Ghernaout, Ahmed Hannachi and Alain Grasmick

The main purpose of this study resides essentially in the development of a new tool to quantify the biomass in the bioreactor operating under steady state conditions.

634

Abstract

Purpose

The main purpose of this study resides essentially in the development of a new tool to quantify the biomass in the bioreactor operating under steady state conditions.

Design/methodology/approach

Modeling is the most relevant tool for understanding the functioning of some complex processes such as biological wastewater treatment. A steady state model equation of activated sludge model 1 (ASM1) was developed, especially for autotrophic biomass (XBA) and for oxygen uptake rate (OUR). Furthermore, a respirometric measurement, under steady state and endogenous conditions, was used as a new tool for quantifying the viable biomass concentration in the bioreactor.

Findings

The developed steady state equations simplified the sensitivity analysis and allowed the autotrophic biomass (XBA) quantification. Indeed, the XBA concentration was approximately 212 mg COD/L and 454 mgCOD/L for SRT, equal to 20 and 40 d, respectively. Under the steady state condition, monitoring of endogenous OUR permitted biomass quantification in the bioreactor. Comparing XBA obtained by the steady state equation and respirometric tool indicated a percentage deviation of about 3 to 13%. Modeling bioreactor using GPS-X showed an excellent agreement between simulation and experimental measurements concerning the XBA evolution.

Originality/value

These results confirmed the importance of respirometric measurements as a simple and available tool for quantifying biomass.

Details

Arab Gulf Journal of Scientific Research, vol. 42 no. 3
Type: Research Article
ISSN: 1985-9899

Keywords

Access Restricted. View access options
Article
Publication date: 7 December 2021

Sayan Chakraborty, Raviarun Arumugaraj Nadar and Aviral Tiwari

A major component in managing pandemic outbreaks involves testing the suspected individuals and isolating them to avoid transmission in the community. This requires setting up…

210

Abstract

Purpose

A major component in managing pandemic outbreaks involves testing the suspected individuals and isolating them to avoid transmission in the community. This requires setting up testing centres for diagnosis of the infected individuals, which usually involves movement of either patient from their residence to the testing centre or personnel visiting the patient, thus aggregating the risk of transmission to localities and testing centres. The purpose of this paper is to investigate and minimize such movements by developing a drone assisted sample collection and diagnostic system.

Design/methodology/approach

Effective control of an epidemic outbreak calls for a rapid response and involves testing suspected individuals and isolating them to avoid transmission in the community. This paper presents the problem in a two-phase manner by locating sample collection centres while assigning neighbourhoods to these collection centres and thereafter, assigning collection centres to nearest testing centres. To solve the mathematical model, this study develops a mixed-integer linear programming model and propose an integrated genetic algorithm with a local search-based approach (GA-LS) to solve the problem.

Findings

Proposed approach is demonstrated as a case problem in an Indian urban city named Kolkata. Computational results show that the integrated GA-LS approach is capable of producing good quality solutions within a short span of time, which aids to the practicality in the circumstance of a pandemic.

Social implications

The COVID-19 pandemic has shown that the large-scale outbreak of a transmissible disease may require a restriction of movement to take control of the exponential transmission. This paper proposes a system for the location of clinical sample collection centres in such a way that drones can be used for the transportation of samples from the neighbourhood to the testing centres.

Originality/value

Epidemic outbreaks have been a reason behind a major number of deaths across the world. The present study addresses the critical issue of identifying locations of temporary sample collection centres for drone assisted testing in major cities, which is by its nature unique and has not been considered by any other previous literature. The findings of this study will be of particular interest to the policy-makers to build a more robust epidemic resistance.

Details

Journal of Global Operations and Strategic Sourcing, vol. 15 no. 2
Type: Research Article
ISSN: 2398-5364

Keywords

Access Restricted. View access options
Article
Publication date: 19 May 2023

Akilimali Ndatabaye Ephrem and McEdward Murimbika

As good as existing measurements of entrepreneurial potential (EP) may appear in the literature, they are fragmented, suffer from the lack of theory integration and clarity, are…

401

Abstract

Purpose

As good as existing measurements of entrepreneurial potential (EP) may appear in the literature, they are fragmented, suffer from the lack of theory integration and clarity, are inadequately specified and assessed and the dimensions are unordered by importance. These limitations of EP metrics have hindered entrepreneurial practice and theory advancement. There is a risk of atomistic evolution of the topic among “siloed” scholars and room for repetitions without real progress. The purpose of this paper was to take stock of existing measurements from which the authors developed a new instrument that is brief and inclusive.

Design/methodology/approach

The authors followed several steps to develop and validate the new instrument, including construct domain name specification, literature review, structured interviews with entrepreneurs, face validation by experts, semantic validation and statistical validation after two waves of data collected on employee and entrepreneur samples.

Findings

A clear operational definition of EP is proposed and serves as a starting point towards a unified EP theory. The new EP instrument is made up of 34 items classified into seven dimensions, which in order of importance are proactive innovativeness, management skill, calculated risk-taking, social skill, financial literacy, entrepreneurial competencies prone to cognitive and heuristic biases and bricolage. The authors provide evidence for reliability and validity of the new instrument.

Research limitations/implications

Although a model is not the model, the authors discuss several ways in which the new measurement model can be used by different stakeholders to promote entrepreneurship.

Originality/value

The authors discuss the domain representativeness of the new scale and argue that the literature can meaningfully benefit from a non-fuzzy approach to what makes the EP of an individual. By developing a new EP instrument, the authors set an important pre-condition for advancing entrepreneurial theory and practice.

Details

Journal of Research in Marketing and Entrepreneurship, vol. 26 no. 1
Type: Research Article
ISSN: 1471-5201

Keywords

Available. Open Access. Open Access
Article
Publication date: 15 October 2024

Amira Sadik Elsayed, Rehab El Siedy and Islam Kamal Mustafa

This paper delves into the traditional ecological knowledge (TEK) and practices of Burj Rashid, an ancient historical city on Egypt’s northern coast, which stands at the meeting…

229

Abstract

Purpose

This paper delves into the traditional ecological knowledge (TEK) and practices of Burj Rashid, an ancient historical city on Egypt’s northern coast, which stands at the meeting point of the Nile’s western branch and the Mediterranean Sea. Burj Rashid boasts a strategic location and rich natural resources and has a long history of relationships between land, people, river, sea and climate change, serving as a model for residents’ adaptation to their ever-changing surroundings.

Design/methodology/approach

Climate studies have exposed the village’s vulnerability to climate and topographical hazards such as rising temperatures, shifting weather patterns, decreasing precipitation, encroaching seas due to sea level rise, coastal erosion and high soil salinization. These factors pose a high risk of water scarcity, crop failure in the medium term, potential famine in the long term and declining fish populations, threatening fishing communities. To address these challenges, the Net Zero: Heritage for Climate Action project - launched by the International Centre for the Study of the Preservation and Restoration of Cultural Property (ICCROM) and the First Aid and Resilience for Culture in Times of Crisis program, funded by Swedish Postcode - proposes a research and development methodology through a platform that weaves together heritage knowledge and climate science. The Egyptian Heritage Rescue Foundation has implemented a platform in Burj Rashid as an innovative site to study risks, vulnerabilities and capacities.

Findings

The project will explore root causes, identify risk scenarios and establish a stakeholder map to guide the development of mitigation strategies and resilience-building measures.

Originality/value

By harnessing the wisdom of TEK and integrating it with scientific knowledge, the project paves the way for innovative climate change adaptation strategies that ensure the long-term sustainability of Burj Rashid’s unique cultural heritage.

Details

Journal of Cultural Heritage Management and Sustainable Development, vol. 14 no. 5
Type: Research Article
ISSN: 2044-1266

Keywords

Access Restricted. View access options
Article
Publication date: 21 July 2022

Rehab El-Gamal, Khaled El-Nagar, Nagwa A. Tharwat and Gomaa Abdel-Maksoud

This study aims to use whiteness (WI) and yellowness indices (YI) that were calculated from the International Commission on Illumination (CIE) color parameter to evaluate the…

146

Abstract

Purpose

This study aims to use whiteness (WI) and yellowness indices (YI) that were calculated from the International Commission on Illumination (CIE) color parameter to evaluate the efficiency of some triazole fungicides [propiconazole (C15H17Cl2N3O2) and tebuconazole (C16H22ClN3O)] to protect wooden artifacts from fungal deterioration.

Design/methodology/approach

Archeological wooden samples were collected from some historical Islamic buildings in Cairo, Egypt. Three species of fungi were identified in previous work. Propiconazole and tebuconazole with different concentrations treated the infected wooden samples aged for different periods. WI and YI of studied samples were measured using UV spectrophotometer. Calibration and uncertainty estimation accompanied by color measurement were studied.

Findings

Studying the uncertainty sources of diffuse reflection of the standard white tiles revealed that the uncertainty of calibration for both the spectrophotometer and white tiles had the highest contribution. The treated samples with tebuconazole and propiconazole fungicides gave good resistance against fungal deterioration at 0.50% for WI and YI.

Originality/value

This study presents the importance of colorimetry in the conservation field because they are considered one of the most important criteria to evaluate conservation materials. From color measurements and their uncertainties, it became clear that triazole fungicides have good efficiency in the protection of wooden artifacts from fungal deterioration. The value of this study is that propiconazole and tebuconazole fungicides at 0.50% can be applied to archaeological wood that is endangered to improper conditions, especially in the case of high levels of relative humidity.

Details

Pigment & Resin Technology, vol. 53 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

Access Restricted. View access options
Article
Publication date: 16 June 2023

Gomaa Abdel-Maksoud, Hanaa Nasr, Sayed Hussein Samaha and Mahmoud Saad ELdeen Kassem

This study aims to evaluate the state of preservation of one of the most famous manuscripts dated back to the 15th century using some analytical techniques to identify the…

246

Abstract

Purpose

This study aims to evaluate the state of preservation of one of the most famous manuscripts dated back to the 15th century using some analytical techniques to identify the manuscript components, explain its deterioration mechanisms and produce some solutions for conservation processes in future studies.

Design/methodology/approach

The analytical techniques used were visual assessment, digital microscope, scanning electron microscope (SEM) with EDX, pH measurement, attenuated total reflection – Fourier transform infrared spectroscopy (ATR/FTIR) and cellulose crystallinity.

Findings

Stains, missed parts and scratching were the most common aspects of deterioration. Some insects were observed by digital microscope. The SEM showed that linen fibers and goat skin were used to manufacture paper sheets and leather binding. Energy dispersive X-ray analysis proved that niobium and tantalum were added during the manufacture of paper sheets. Carbon black ink was the main writing material. The other pigments used were cinnabar in red ink, gold color from brass and blue color from lapis lazuli. FTIR analysis proved that some chemical changes were noticed. Low crystallinity of the historical paper was obtained. There was a reduction in the pH value of the historical bookbinding.

Originality/value

The importance of the analytical techniques used to detect the main components, forms and mechanism of deterioration of the studied manuscript. The elements of niobium and tantalum were added to paper sheets, which protected them from deterioration. The insects such as house flies and Sitophilus granarius were found in the manuscripts.

Details

Pigment & Resin Technology, vol. 53 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

1 – 10 of 10
Per page
102050