Search results

1 – 10 of 16
Per page
102050
Citations:
Loading...
Access Restricted. View access options
Article
Publication date: 8 May 2018

Mohammed Ahmed Al-Bukhaiti, Ahmed Abouel Kasem Mohamad, Karam Mosa Emara and Shemy M. Ahmed

This paper aims to investigate the influence of slurry concentration on the erosion behavior of AISI 5117 steel and high-chromium white cast iron by using a whirling-arm rig. In…

126

Abstract

Purpose

This paper aims to investigate the influence of slurry concentration on the erosion behavior of AISI 5117 steel and high-chromium white cast iron by using a whirling-arm rig. In this study, the slurry erosion mechanism with particle concentration has been studied.

Design/methodology/approach

The tests were carried out with particle concentrations in the range of 1-7 Wt.%, and the impact velocity of slurry stream was 15 m/s. Silica sand with a nominal size range of 500-710 µm was used as an erodent. The study revealed that the failure mode was independent of concentration.

Findings

The results showed that the erosion rate decreases with the increase in particle concentration and the variation in the reduction depends on the material. It was found that the variation of fractal dimension calculated from slope of linearized power spectral density of eroded surface image for different concentrations can be used to characterize the slurry erosion intensity in a similar manner to the erosion rate. It was also found that the variation of fractal dimension versus concentration of sand has a general trend that does not depend on magnification factor.

Originality/value

Using the gravitational measurement and image analysis, the variation of the wear with slurry concentration has been analyzed to investigate the implicated mechanisms of erosion during the process.

Details

Industrial Lubrication and Tribology, vol. 70 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

Access Restricted. View access options
Article
Publication date: 7 August 2018

Yasser Abdelrhman, Ahmed Abouel-Kasem, Karam Emara and Shemy Ahmed

This paper aims to clarify the relationship between the slurry erosion and one of the case hardening treatments, i.e. boronizing in this study, for AISI-5117 steel alloy…

272

Abstract

Purpose

This paper aims to clarify the relationship between the slurry erosion and one of the case hardening treatments, i.e. boronizing in this study, for AISI-5117 steel alloy. AISI-5117 steel alloy was used because of its variety applications in the field of submarine equipment. Most of the slurry erosion factors such as velocity, impact angle and mechanism of erosion were studied at different impact angles.

Design/methodology/approach

At first, the samples were prepared and subjected to the boronizing treatment in controlled atmosphere. By using a slurry erosion test-rig, all experiments for studying the slurry erosion factors were carried out. Moreover, the studied specimens were investigated via scanning electron microscope, optical microscope and X-ray diffraction to study the erosion mechanism in the different conditions.

Findings

It was expected that the boronization of the AISI-5117 steel would increase its slurry erosion resistance due to its positive impact on the surface hardness. However, the results observed show the opposite, where the boronization of AISI-5117 steel decreased its slurry erosion resistance as implied by the increase of the mass loss percentage at all impact angles.

Originality/value

This research, for the first time, exhibits the effect of boronizing treatment on the slurry erosion in different impact factors accompanied by the erosion mechanism at each impact angle.

Details

Industrial Lubrication and Tribology, vol. 70 no. 7
Type: Research Article
ISSN: 0036-8792

Keywords

Access Restricted. View access options
Article
Publication date: 4 September 2017

Bahaa Saleh, A. Abouel-Kasem and Shemy Ahmed

This paper aimed to analyze removed particles from stationary specimen-aluminum (Al-99.92) produced by vibratory cavitation erosion tests in distilled water and glycerol-water…

164

Abstract

Purpose

This paper aimed to analyze removed particles from stationary specimen-aluminum (Al-99.92) produced by vibratory cavitation erosion tests in distilled water and glycerol-water mixtures.

Design/methodology/approach

The particle morphology which include particle surface topography, size distribution, particle size parameters and particle shape parameters were examined for distilled water and glycerol-water mixtures having different viscosities.

Findings

The results showed that the variation of size parameters with viscosity was very similar to the variation of weight loss with viscosity. Both the size parameters and weight losses show a monotonic decrease in going from distilled water to glycerol-water mixtures having viscosity about 10.1 cSt, beyond which the change is very small. On the other hand, the shape parameters were much less sensitive to distinguish between the particles produced in water and glycerol-water mixtures. The mechanism of cavitation erosion is investigated in detail through observations of the removed particles. The particle surfaces topography demonstrated that the mechanism in water and glycerol-water mixtures was fatigue failure.

Originality/value

Cavitation often occurs in almost all machines that handle liquids, especially at high speeds, leading to irreparable damage of the components of these machines. Elucidation of such complex phenomenon demands full characterization of the erosion mechanism and controlling parameters inherent to it, so that cavitation erosion can be prevented or at least be reduced through adequate information and collection of relevant data under different operating conditions. Very few studies have been made to approach the viscosity effect upon cavitation erosion from the particle analysis standpoint. The aim of the present work is to identify the effect of liquid viscosity on the size, shape characteristics of the erosion particles and their morphological features. The prevailed mechanisms of wear and particle generation have been proposed based on the acquired information from particle analysis.

Details

Industrial Lubrication and Tribology, vol. 69 no. 5
Type: Research Article
ISSN: 0036-8792

Keywords

Access Restricted. View access options
Article
Publication date: 20 October 2021

Neda Hassanpour, Ali Shaemi Barzoki, Mohammad Hossein Moshref Javadi and Ali Safari

This study aimed at developing and testing a model to evaluate employee performance in Isfahan municipality.

753

Abstract

Purpose

This study aimed at developing and testing a model to evaluate employee performance in Isfahan municipality.

Design/methodology/approach

A mixed-method design is applied in this study. To extract the model, a semi-structured interview based on the thematic analysis approach was employed. The qualitative data were obtained using a researcher-made questionnaire from a sample of 12 municipal experts selected based on purposive sampling. In the quantitative phase, the sample consisted of 76 managers and interim managers. The validity of the questionnaire was determined by the content validity index, while the structural validity was tested based on structural equation modeling using SmartPLS software. The reliability of the questionnaire was confirmed using Cronbach's alpha and composite reliability indices.

Findings

The factors obtained in the qualitative model included performance evaluation criteria, the desired time interval for performance evaluation, results announcement, performance evaluation approach, performance evaluation method and evaluator-related variables. There should have been an agreement between evaluators and those who were evaluated in all components of the model. In the quantitative section, performance evaluation criteria, evaluators, the evaluation method and time interval were confirmed with coefficients of 0.871, 0.815, 0.646 and 0.615, respectively.

Practical implications

The novelty of this study is that it uses a mixed-method research approach to extract a performance evaluation model that is specific to the Isfahan municipality.

Originality/value

The novelty of this study is that it uses a mixed-method research approach to extract a performance evaluation model that is specific to the Isfahan municipality.

Details

International Journal of Productivity and Performance Management, vol. 71 no. 6
Type: Research Article
ISSN: 1741-0401

Keywords

Access Restricted. View access options
Article
Publication date: 25 March 2024

Mostafa Abdel-Hamied, Ahmed A.M. Abdelhafez and Gomaa Abdel-Maksoud

This study aims to focus on the main materials used in consolidation processes of illuminated paper manuscripts and leather binding.

153

Abstract

Purpose

This study aims to focus on the main materials used in consolidation processes of illuminated paper manuscripts and leather binding.

Design/methodology/approach

For each material, chemical structure, chemical composition, molecular formula, solubility, advantages, disadvantages and its role in treatment process are presented.

Findings

This study concluded that carboxy methyl cellulose, hydroxy propyl cellulose, methyl cellulose, cellulose acetate, nanocrystalline cellulose, funori, sturgeon glue, poly vinyl alcohol, chitosan, chitosan nanoparticles (NPs), gelatin, aquazol, paraloid B72 and hydroxyapatite NPs were the most common and important materials used for the consolidation of illuminated paper manuscripts. For the leather bindings, hydroxy propyl cellulose, polyethylene glycol, oligomeric melamine-formaldehyde resin, acrylic wax SC6000, pliantex, paraloid B67 and B72, silicone oil and collagen NPs are the most consolidants used.

Originality/value

Illuminated paper manuscripts with leather binding are considered one of the most important objects in libraries, museums and storehouses. The uncontrolled conditions and other deterioration factors inside the libraries and storehouses lead to degradation of these artifacts. The brittleness, fragility and weakness are considered the most common deterioration aspects of illuminated paper manuscripts and leather binding. Therefore, the consolidation process became vital and important to solve this problem. This study presents the main materials used for consolidation process of illuminated paper manuscripts and leather bindings.

Details

Pigment & Resin Technology, vol. 54 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

Access Restricted. View access options
Article
Publication date: 20 October 2021

Gomaa Abdel-Maksoud, Mostafa Abdel-Hamied and Ahmed A.M. Abdelhafez

This paper aims to present the components' characterization and condition assessment of an important deteriorated Mamluk-illuminated paper manuscript housed in Al-Azhar Library…

550

Abstract

Purpose

This paper aims to present the components' characterization and condition assessment of an important deteriorated Mamluk-illuminated paper manuscript housed in Al-Azhar Library, Egypt.

Design/methodology/approach

Different analytical techniques used in this study were the portable digital optical microscope, stereomicroscope, scanning electron microscope with EDX (SEM.EDX), portable X-ray fluorescence (pXRF), X-ray diffraction (XRD), pH measurement and Fourier transform infrared spectroscopy (FTIR).

Findings

The results obtained by different microscopes showed that the gilding in the surface of illuminated paper sheets was performed with gold leaves. Additionally, these microscopes revealed that the illuminated paper manuscript has different aspects of deterioration such as adhered dirt, staining, some micro-cracks, cracks and detachment of some parts in some illuminated areas. The results of elemental analysis by EDX, portable XRF and XRD analysis showed that the orange red pigment is red lead (Pb3O4), blue pigment is azurite (2CuCo3.Cu (OH)2), and the gold layer is has consisted of brass alloy (Cu-Zn) with a small amount of gold element (Au). The pH measurement stated that the historical paper in the acidity level. The ATR-FTIR analysis also revealed the oxidation of cellulose. Moreover, it was found from ATR-FTIR that Arabic gum was used as a binder for the pigments.

Originality/value

This study presents the important results of analytical methods used for condition assessment and identification of the components of an important Mamluk-illuminated paper manuscript, where these results referred that the studied paper manuscript had different aspects of deterioration. The conservation steps either conservation treatment or preventive conservation are urgently needed in future studies.

Details

Pigment & Resin Technology, vol. 52 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

Access Restricted. View access options
Article
Publication date: 13 February 2024

Nagla Elshemy, Mona Ali and Reem Nofal

The purpose of this study is to successfully apply ultrasonic waves for the quick extraction of flax seed gum from flaxseed hull or whole seed and compare it to the standard…

74

Abstract

Purpose

The purpose of this study is to successfully apply ultrasonic waves for the quick extraction of flax seed gum from flaxseed hull or whole seed and compare it to the standard technique of extraction.

Design/methodology/approach

The effect of the heating source, extracted time, temperature and pH of extracted solution on the extraction was studied. The obtained gum is subsequently used for silk screen printing on cotton, linen and viscous fabrics. Rheological properties and viscosity of the printing paste were scrutinized in the current study to get a better insight into this important polysaccharide. The output of this effort aimed to specify the parameters of the processes for printing textiles to serve in women’s fashion clothes by applying innovated handmade combinations of Islamic art motives using a quick and affordable method. Seven designs are executed, and inspiring from them, seven fashion designs of ladies’ clothes were designed virtually by Clo 3D software.

Findings

The result recorded that the new gum has excellent printing properties. In addition, they have better rheological properties, viscosity, chromatic strength and fastness qualities, all of which could help them in commercial production.

Research limitations/implications

Flaxseed and three different fabric types (Cotton, Linen and Viscous) were used.

Practical implications

Synthesis of a new biodegradable thickener from a natural resource, namely, flaxseed, by applying new technology to save time, water and energy.

Originality/value

Synthesis of eco-friendly biodegradable thickener and used in textile printing alternative to the synthetic thickener.

Details

Research Journal of Textile and Apparel, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1560-6074

Keywords

Available. Open Access. Open Access
Article
Publication date: 15 April 2022

Seyedeh Zahra Zamani

This paper aims to map the influential concepts on technology adoption in Small and Medium Enterprises (SMEs) through conducting a systematic literature review and finding a…

26479

Abstract

Purpose

This paper aims to map the influential concepts on technology adoption in Small and Medium Enterprises (SMEs) through conducting a systematic literature review and finding a better understanding of the current body of knowledge.

Design/methodology/approach

A systematic literature review approach is taken here, which includes the following steps: Determination of keywords and strings, selection of databases, setting inclusion and exclusion criteria, conducting the search in chosen databases over a specific period of time. This process has led to the final count of 349 peer-reviewed articles being studied, and the results are analyzed quantitatively and qualitatively.

Findings

As a result of the study, 11 categories of influential concepts on technology adoption are identified by reviewing literature from the past decade. This article indicates how fragmented the literature is and how it concentrates on studying the impact of only a limited number of categories of concepts. The scatted frameworks (theoretical and conceptual) and weak application of the used theories found in this research also highlight the need for the development of a framework that looks into technology adoption as a dynamic process due to the dynamic nature of new technologies today.

Research limitations/implications

Based on the above findings, future research avenues are to look into technology adoption from a process perspective, to dig into less researched influencing concepts such as infrastructure, regulations, strategy and resources and their role in adoption of technology in SMEs as well as development of a framework for technology adoption that is aligned with these elements.

Practical implications

Practitioners and policymakers will benefit from finding a helicopter view of the barriers and supporting factors throughout their technology adoption journey. The knowledge they gain from this study will better prepare them in building tools they need for adopting technology in their organizations and provide an in-depth insight to what elements can affect their journey.

Originality/value

This review provides an insight into the current body of knowledge on the topic, which researchers can benefit from constructing an in-depth understanding of the state of research as well as influencing concepts of technology adoption in SMEs. Moreover, it adds value in building up the knowledge of technology adoption in today's dynamic world of digitalization.

Details

European Journal of Innovation Management, vol. 25 no. 6
Type: Research Article
ISSN: 1460-1060

Keywords

Access Restricted. View access options
Article
Publication date: 31 May 2024

Fareed ud din Qureshi

This study aims to investigate the impact of dissimilarity perceptions, specifically related to religious identity and socioeconomic class, on identity disclosure behavior within…

262

Abstract

Purpose

This study aims to investigate the impact of dissimilarity perceptions, specifically related to religious identity and socioeconomic class, on identity disclosure behavior within the workplace. It also explores the relationship between disclosure behavior and perceptions of workplace ostracism. The study further examines the moderating roles of psychological safety climate and diversity-focused human resource (HR) practices in these dynamics.

Design/methodology/approach

Using quantitative methods, this confirmatory study analyzes the relationships between dissimilarity perceptions, identity disclosure behavior, workplace ostracism perceptions, psychological safety climate and diversity-focused HR policies. Hypotheses are tested to understand the effects of these variables in the workplace context.

Findings

The findings reveal that subjective dissimilarity perceptions are negatively associated with identity disclosure behavior. In addition, disclosure behavior is positively linked to perceptions of workplace ostracism. Surprisingly, the study finds that the psychological safety climate moderates the relationship between dissimilarity perceptions and identity disclosure behavior, showing a positive relationship when psychological safety climate perceptions are high. Furthermore, perceptions of diversity-focused HR policies moderate the relationship between disclosure behavior and perceptions of workplace ostracism, indicating a weakened relationship when diversity-focused HR practices are perceived as stronger.

Originality/value

This study contributes to the understanding of workplace diversity, inclusion and management by emphasizing the role of subjective dissimilarity perceptions, identity disclosure behavior and workplace ostracism. It explores the moderating influence of psychological safety climate and diversity-focused HR practices, offering valuable insights for both theory and practical strategies in the context of diversity management.

Details

Journal of Asia Business Studies, vol. 18 no. 4
Type: Research Article
ISSN: 1558-7894

Keywords

Access Restricted. View access options
Article
Publication date: 14 December 2023

Prathamesh Gaikwad and Sandeep Sathe

The purpose of this paper is to study and analyze the effects of fly ash (FA) as a mineral admixture on compressive strength (CS), carbonation resistance and corrosion resistance…

233

Abstract

Purpose

The purpose of this paper is to study and analyze the effects of fly ash (FA) as a mineral admixture on compressive strength (CS), carbonation resistance and corrosion resistance of reinforced concrete (RC). In addition, the utilization of inexpensive and abundantly available FA as a cement replacement in concrete has several benefits including reduced OPC usage and elimination of the FA disposal problem.

Design/methodology/approach

Reinforcement corrosion and carbonation significantly affect the strength and durability of the RC structures. Also, the utilization of FA as green corrosion inhibitors, which are nontoxic and environmentally friendly alternatives. This review discusses the effects of FA on the mechanical characteristics of concrete. Also, this review analyzes the impact of FA as a partial replacement of cement in concrete and its effect on the depth of carbonation in concrete elements and the corrosion rate of embedded steel as well as the chemical composition and microstructure (X-ray diffraction analysis and scanning electron microscopy) of FA concrete were also reviewed.

Findings

This review provides a clear analysis of the available study, providing a thorough overview of the current state of knowledge on this topic. Regarding concrete CS, the findings indicate that the incorporation of FA often leads to a loss in early-age strength. However, as the curing period increased, the strength of fly ash concrete (FAC) increased with or even surpassed that of conventional concrete. Analysis of the accelerated carbonation test revealed that incorporating FA into the concrete mix led to a shallower carbonation depth and slower diffusion of carbon dioxide (CO2) into the concrete. Furthermore, the half-cell potential test shows that the inclusion of FA increases the durability of RC by slowing the rate of steel-reinforcement corrosion.

Originality/value

This systematic review analyzes a wide range of existing studies on the topic, providing a comprehensive overview of the research conducted so far. This review intends to critically assess the enhancements in mechanical and durability attributes (such as CS, carbonation and corrosion resistance) of FAC and FA-RC. This systematic review has practical implications for the construction and engineering industries. This can support engineers and designers in making informed decisions regarding the use of FA in concrete mixtures, considering both its benefits and potential drawbacks.

Details

World Journal of Engineering, vol. 22 no. 1
Type: Research Article
ISSN: 1708-5284

Keywords

1 – 10 of 16
Per page
102050