Search results

1 – 8 of 8
To view the access options for this content please click here
Article
Publication date: 30 August 2013

Hassan Salah Aly Emira, Yosreya Mostafa Abu‐Ayana and Sanaa Mohammad El‐Sawy

The purpose of this paper is to study the corrosion protective properties of modified urea and/or thiourea formaldehyde resins for steel surface.

Abstract

Purpose

The purpose of this paper is to study the corrosion protective properties of modified urea and/or thiourea formaldehyde resins for steel surface.

Design/methodology/approach

Three butyl alcohol modified amino resins were laboratory prepared. The three modified resins were characterized using thermal gravimetric analysis and infrared; the solid content and refractive index of each were also measured.

Findings

The resins that contain both nitrogen and sulphur have excellent corrosion inhibitive activity compared with that containing nitrogen only.

Research limitations/implications

The modified resins were based on urea formaldehyde resin, mixed urea and thiourea formaldehyde resin and thiourea formaldehyde resin, respectively.

Practical implications

The prepared resins were introduced in different coating formulations based on short‐oil alkyd resin, medium‐oil alkyd resin and plasticized chlorinated rubber. They were then tested and evaluated for corrosion protection of steel surfaces.

Originality/value

All the prepared resins show promising results for corrosion protection of steel surfaces.

Details

Pigment & Resin Technology, vol. 42 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

To view the access options for this content please click here
Article
Publication date: 18 February 2019

Mohammed S. Gumaan, Rizk Mostafa Shalaby, Mustafa Kamal Mohammed Yousef, Esmail A.M. Ali and E. E. Abdel-Hady

This study aims to investigate the structural, mechanical, thermal and electrical properties of tin–silver–nickel (Sn-Ag-Ni) melt-spun solder alloys. So, it aims to…

Abstract

Purpose

This study aims to investigate the structural, mechanical, thermal and electrical properties of tin–silver–nickel (Sn-Ag-Ni) melt-spun solder alloys. So, it aims to improve the mechanical properties of the eutectic tin–silver (Sn-Ag) such as tensile strength, plasticity and creep resistance by adding different concentrations of Ni content.

Design/methodology/approach

Ternary melt-spun Sn-Ag-Ni alloys were investigated using x-ray diffractions, scanning electron microscope, dynamic resonance technique (DRT), Instron machine, Vickers hardness tester and differential scanning calorimetry.

Findings

The results revealed that the Ni additions 0.1, 0.3, 0.5, 0.7, 1, 3 and 5 Wt.% to the eutectic Sn-Ag melt-spun solder were added. The “0.3wt.%” of Ni was significantly improved its mechanical properties to efficiently serve under high strain rate applications. Moreover, the uniform distribution of Ag3Sn intermetallic compound with “0.3wt.%” of Ni offered the potential benefits, such as high strength, good plasticity consequently and good mechanical performance through a lack of dislocations and microvoids. The tensile results showed improvement in 17.63 per cent tensile strength (26 MPa), 21 per cent toughness (1001 J/m3), 22.83 per cent critical shear stress (25.074 MPa) and 11 per cent thermal diffusivity (2.065 × 10−7 m2/s) when compared with the tensile strength (21.416 MPa), toughness (790 J/m3), critical shear stress (19.348 MPa) and thermal diffusivity (1.487 × 10−7 m2/s) of the eutectic Sn-Ag. Slight increments have been shown for the melting temperature of Sn96.2-Ag3.5-Ni0.3 (222.62°C) and electrical resistivity to (1.612 × 10−7 Ω.m). It can be said that the eutectic Sn-Ag solder alloy has been mechanically improved with “0.3wt.%” of Ni to become a suitable alloy for high strain rate applications. The dislocation movement deformation mechanism (n = 4.5) without Ni additions changed to grain boundary sliding deformation mechanism (n = 3.5) with Ni additions. On the other hand, the elastic modulus, creep rate and strain rate sensitivity with “0.3wt.%” of Ni have been decreased. The optimum Ni-doped concentration is “0.7wt.%” of Ni in terms of refined microstructure, electrical resistivity, Young’s Modulus, bulk modulus, shear modulus, thermal diffusivity, maximum shear stress, tensile strength and average creep rate.

Originality/value

This study provides nickel effects on the structural of the eutectic Sn-Ag rapidly solidified by melt-spinning technique. In this paper, the authors have compared the elastic modulus of the melt-spun compositions which has been resulted from the tensile strength tester with these results from the DRT for the first time to best of the authors’ knowledge. This paper presents new improvements in mechanical and electrical performance.

Details

Soldering & Surface Mount Technology, vol. 31 no. 1
Type: Research Article
ISSN: 0954-0911

Keywords

To view the access options for this content please click here
Article
Publication date: 16 December 2019

Sanaa Razzaq Abbas, Mohammed S. Gumaan and Rizk Mostafa Shalaby

This study aims to investigate the chromium (Cr) effects on the microstructural, mechanical and thermal properties of melt-spun Sn-3.5Ag alloy.

Abstract

Purpose

This study aims to investigate the chromium (Cr) effects on the microstructural, mechanical and thermal properties of melt-spun Sn-3.5Ag alloy.

Design/methodology/approach

Ternary melt-spun Sn-Ag-Cr alloys were investigated using X-ray diffractions, scanning electron microscope, dynamic resonance technique, instron machine, Vickers hardness tester and differential scanning calorimetry.

Findings

The results revealed that the Ag3Sn intermetallic compound (IMC) and ß-Sn have been refined because of the hard inclusions’ (Cr atoms) effects, causing lattice distortion increasing these alloys. The tensile results of Sn96.4-Ag3.5-Cr0.1 alloy showed an improvement in Young’s modulus more than 100 per cent (42.16 GPa), ultimate tensile strength (UTS) by 9.4 per cent (23.9 MPa), compared with the eutectic Sn-Ag alloy due to the high concentration of Ag3Sn and their uniform distribution. Shortage in the internal friction (Q−1) of about 54 per cent (45.1) and increase in Vickers hardness of about 7.4 per cent (142.1 MPa) were also noted. Hexagonal Ag3Sn formation led to low toughness values compared to the eutectic Sn-Ag alloy, which may have resulted from the mismatching among hexagonal Ag3Sn phase with orthorhombic Ag3Sn and ß-Sn phases. Mechanically, the values of Young’s modulus have been increased, with increasing chromium content, whereas the UTS and toughness values have been decreased. The opposite of this trend appeared in Sn95.8-Ag3.5-Cr0.7 alloy, which may have been due to high lattice distortion (ƹ = 16.5 × 10−4) compared to the other alloys. Increase in the melting temperature Tm, ΔH, Cp and ΔT was because of Ag3Sn IMC formation. The low toughness of Sn96-Ag3.5-Cr0.5 and Sn95.8-Ag3.5-Cr0.7 (109.56 J/m3 and 35.66 J/m3), relatively high melting temperature Tm (223.22°C and 222.65°C) and low thermal conductivity and thermal diffusivity (32.651 w.m−1.k−1 and 0.314 m2/s) make them undesirable in the soldering process. The high UTS, high E, high thermal conductivity and diffusivity, low creep rate and low electrical resistivity, which have occurred with “0.1 Wt.%” of Cr, make this alloy desirable and reliable for soldering applications and electronic assembly.

Originality/value

This study provides chromium effects on the structure of the eutectic Sn-Ag rapidly solidified by melt-spinning technique. In this paper, the authors compared the elastic modulus of the melt-spun compositions, which have been resulted from the Static method with that have been resulted from the Dynamic method. This paper presents new improvements in mechanical and thermal performance.

Details

Soldering & Surface Mount Technology, vol. 32 no. 3
Type: Research Article
ISSN: 0954-0911

Keywords

To view the access options for this content please click here
Article
Publication date: 12 June 2017

Murad Mohammed Al-Nashmi and Abdulkarim Abdullah Almamary

In an effort to build a useful conceptual framework that enhances understanding and permits practical application of ethics, this paper aims to understand the relationship…

Abstract

Purpose

In an effort to build a useful conceptual framework that enhances understanding and permits practical application of ethics, this paper aims to understand the relationship and impact of Islamic marketing ethics on brand credibility. Nowadays, recognizing the ethical dilemmas associated with business is an important aspect of marketing strategy (Murphy et al. 2012). As known, the pharmaceutical industry has access to a deep pool of resources with the potential to maintain an esteemed reputation for offering innovative products that improve the public’s health and well-being (Kim and Ball, 2013). However, recent years have yielded several high-profile safety issues associated with particular medications along with a growing perception that pharmaceutical companies are unethical and drive up healthcare costs by prioritizing profits over consumer needs (USA Today/KFF/Harvard SPH, 2008). Therefore, the reputation of the pharmaceutical industry has been damaged with only 11 per cent of individuals considering pharmaceutical companies to be trustworthy (Harris Interactive Poll, 2010). Thus, the pharmaceutical industry in Yemen is the target of this paper and the relationship between its brands’ credibility and Islamic marketing ethics has been highlighted.

Design/methodology/approach

In a study of 106 respondents, exploratory and confirmatory factor analysis were conducted to understand the relationship, between brand credibility and Islamic marketing ethics. Correlation and regression analyses were performed to evaluate the hypothesized relationships between the variables.

Findings

Significant and positive relationships were confirmed between brand credibility and Islamic marketing ethics, namely, Annasihah, Al-Istiqamah, Al-E’etedal, Al-Ihsan, As-Sidq, Attaqwa and Al-Amanah. The eighth Islamic marketing ethic, Attasamoh, has been rejected.

Originality/value

The paper evaluates brand credibility in relation to Islamic marketing ethics in the pharmaceutical industry in Yemen. Islamic marketing ethics have been confirmed as a new variable that correlates with brand credibility and helps in boosting the level of credibility.

Details

Journal of Islamic Marketing, vol. 8 no. 2
Type: Research Article
ISSN: 1759-0833

Keywords

To view the access options for this content please click here
Article
Publication date: 27 May 2021

Rami Farouk Daher

The purpose of this paper is to attempt to provide a critical assessment of the trajectory and nature of the production of knowledge on cultural heritage on the Arab…

Abstract

Purpose

The purpose of this paper is to attempt to provide a critical assessment of the trajectory and nature of the production of knowledge on cultural heritage on the Arab world. This evaluation of the discipline or field of cultural heritage will focus on both a historic evolution and on current practices in order to understand the nature and politics of that evolution.

Design/methodology/approach

The approach and research methodology adopted for this paper depends primarily on a long-term critical literature review and content analysis that took place over the past 25 years concerning key reports, journal articles, books and other publications on cultural heritage on the Arab world.

Findings

The paper's main findings centers on presenting current practices/production on cultural heritage which are divided into two categories in terms of production of knowledge: an abundant engagement with a technical sphere dominated with concern for documentation and conservation technology of cultural heritage; and a scarce engagement with epistemological and theoretical spheres that delves into processes of cultural heritage definition, consumption and continuity in the Arab world.

Originality/value

The paper attempts to engage in and commence a much-needed wider discussion on the historical transformation concerning knowledge production on cultural heritage in the Arab world and its related practices and processes. The paper emphasizes the significance of this engagement with theoretical spheres of conservation and calls for an expansion of such engagement in order to elevate the discourse and debate on cultural heritage in the Arab world.

Details

Archnet-IJAR: International Journal of Architectural Research, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2631-6862

Keywords

To view the access options for this content please click here
Article
Publication date: 21 July 2020

Pierre Rostan and Alexandra Rostan

The purpose of the paper is to forecast economic indicators of the Saudi economy in the context of low oil prices which have taken a toll on the Saudi oil-dependent…

Abstract

Purpose

The purpose of the paper is to forecast economic indicators of the Saudi economy in the context of low oil prices which have taken a toll on the Saudi oil-dependent economy between 2014 and 2017. Trades and investments have plummeted, leading to significant budget deficits. In response, the government unveiled a plan called Saudi Vision 2030 in 2016 which has triggered structural economic reforms leading to an unprecedented strategy of transition from an oil-driven economy to a modern market economy.

Design/methodology/approach

This paper forecasts with spectral analysis economic indicators of the Saudi economy up to 2030 to provide a clearer picture of the future economy assuming that the effects of recent reforms have not yet been traced by most of the economic indicators.

Findings

2018–2030 forecasts are all bearish except West Texas Intermediate (WTI) oil price expected to average $64.40 during the period 2019–2030. Two additional exceptions are the Saudi population that should grow to 40 million in 2030 and the swelling gross domestic product (GDP) generated by the non-oil sector resulting from bold actions of the Saudi government who is willing to become less dependent on revenues generated by the oil sector.

Research limitations/implications

Government policymakers, economists and investors would have with spectral forecasts better insight and understanding of the Saudi economy dynamics at the early stage of major economic reforms implemented in the country. In 2020, the COVID-19 pandemic has brutally hurt the Saudi economy following a collapse in the global demand for oil and an oversupplied industry. The impact on the Saudi economy will depend on the optimal response brought by its government.

Social implications

Saudi Vision 2030 plan has already triggered a deep transformation of the Saudi society that is reviewed in this paper.

Originality/value

The forecast of Saudi economic indicators is a timely topic considering the challenges facing the economy and reforms being undertaken. Applying an original forecasting technique to economic indicators adds to the originality of the paper.

Details

International Journal of Emerging Markets, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1746-8809

Keywords

Content available
Article
Publication date: 1 October 1999

Abstract

Details

Disaster Prevention and Management: An International Journal, vol. 8 no. 4
Type: Research Article
ISSN: 0965-3562

Keywords

To view the access options for this content please click here
Article
Publication date: 3 November 2014

X.R. Zhang, L.Z. Liu, J.F. Li, W.W. Cui and L. Weng

The key purpose of this study was to investigate the effects of different ultrasonic irradiation times on the wettability and other properties of the resulting water-based…

Abstract

Purpose

The key purpose of this study was to investigate the effects of different ultrasonic irradiation times on the wettability and other properties of the resulting water-based coating. The subject water-based coating was prepared using water-soluble polyester and amino resins by ultrasonic oscillation.

Design/methodology/approach

The coating was prepared by polymerising polyester and amino resins in water using ultrasonic oscillation. The coating was baked for 40 seconds at 350°C to coalesce and solidify the film. The contact angle, thermal stability and mechanical properties of the film, as well as the molecular weight (MW) and structure of the polyester resin, were determined.

Findings

The contact angle of the coating was found to decrease with ultrasonic irradiation; the mechanical properties and thermal stability were not altered when the irradiation time was longer than 5 hours. The MW of the polyester initially decreased then increased and stabilized with ultrasonic irradiation. The structure of polyester molecule and aggregated state of the solidified coating were not changed by ultrasonic irradiation.

Research limitations/implications

In the study reported here, the effects of different ultrasonic irradiation times were investigated. Results of this research could benefit in-depth understanding of the influence of ultrasonic treatment on polyester resins and polyester coatings and could further promote the development of water-based coatings.

Originality/value

The contact angle of the water-based coating decreased by mechanical means. The effects of ultrasound on microstructure and properties of the coating and resin were discussed in detail.

Details

Pigment & Resin Technology, vol. 43 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

1 – 8 of 8