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Article
Publication date: 2 February 2023

Shanmugan Subramani and Mutharasu Devarajan

Polymer-based thermal interface materials (TIMs) are having pump out problem and could be resolved for reliable application. Solid-based interface materials have been suggested…

Abstract

Purpose

Polymer-based thermal interface materials (TIMs) are having pump out problem and could be resolved for reliable application. Solid-based interface materials have been suggested and reported. The purpose of this paper is suggesting thin film-based TIM to sustain the light-emiting diode (LED) performance and electronic device miniaturization.

Design/methodology/approach

Consequently, ZnO thin film at various thicknesses was prepared by chemical vapour deposition (CVD) method and tested their thermal behaviour using thermal transient analysis as solid TIM for high-power LED.

Findings

Low value in total thermal resistance (Rth-tot) was observed for ZnO thin film boundary condition than bare Al boundary condition. The measured interface (ZnO thin film) resistance {(Rth-bhs) thermal resistance of the interface layer (thin film) placed between metal core printed circuit board (MCPCB) board and Al substrates} was nearly equal to Ag paste boundary condition and showed low values for ZnO film prepared at 30 min process time measured at 700 mA. The TJ value of LED mounted on ZnO thin film (prepared at 30 min.) coated Al substrates was measured to be 74.8°C. High value in junction temperature difference (ΔTJ) of about 4.7°C was noticed with 30 min processed ZnO thin film when compared with Al boundary condition. Low correlated colour temperature and high luminous flux values of tested LED were also observed with ZnO thin film boundary condition (processed at 30 min) compared with both Al substrate and Ag paste boundary condition.

Originality/value

Overall, 30 min CVD processed ZnO thin film would be an alternative for commercial TIM to achieve efficient thermal management. This will increase the life span of the LED as the proposed material decreases the TJ values.

Details

Microelectronics International, vol. 41 no. 2
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 19 May 2023

Hasan Baş, Fatih Yapıcı and İbrahim İnanç

Binder jetting is one of the essential additive manufacturing methods because it is cost-effective, has no thermal stress problems and has a wide range of different materials…

Abstract

Purpose

Binder jetting is one of the essential additive manufacturing methods because it is cost-effective, has no thermal stress problems and has a wide range of different materials. Using binder jetting technology in the industry is becoming more common recently. However, it has disadvantages compared to traditional manufacturing methods regarding speed. This study aims to increase the manufacturing speed of binder jetting.

Design/methodology/approach

This study used adaptive slicing to increase the manufacturing speed of binder jetting. In addition, a variable binder amount algorithm has been developed to use adaptive slicing efficiently. Quarter-spherical shaped samples were manufactured using a variable binder amount algorithm and adaptive slicing method.

Findings

Samples were sintered at 1250°C for 2 h with 10°C/min heating and cooling ramp. Scanning electron microscope analysis, surface roughness tests, and density calculations were done. According to the results obtained from the analyzes, similar surface quality is achieved by using 38% fewer layers than uniform slicing.

Research limitations/implications

More work is needed to implement adaptive slicing to binder jetting. Because the software of commercial printers is very difficult to modify, an open-source printer was used. For this reason, it can be challenging to produce perfect samples. However, a good start has been made in this area.

Originality/value

To the best of the authors’ knowledge, the actual use of adaptive slicing in binder jetting was applied for the first time in this study. A variable binder amount algorithm has been developed to implement adaptive slicing in binder jetting.

Details

Rapid Prototyping Journal, vol. 29 no. 8
Type: Research Article
ISSN: 1355-2546

Keywords

Open Access
Article
Publication date: 4 May 2023

Md. Bokhtiar Hasan, Md Mamunur Rashid, Md. Naiem Hossain, Mir Mahmudur Rahman and Md. Ruhul Amin

This research explores the spillovers and portfolio implications for green bonds and environmental, social and governance (ESG) assets in the context of the rapidly expanding…

1438

Abstract

Purpose

This research explores the spillovers and portfolio implications for green bonds and environmental, social and governance (ESG) assets in the context of the rapidly expanding trend in green finance investments and the need for a green recovery in the post-COVID-19 era.

Design/methodology/approach

This study utilizes Diebold and Yilmaz’s (2014) spillover method and portfolio strategies (hedge ratio, optimal weights and hedging effectiveness) for the data starting from February 29, 2012, to March 14, 2022.

Findings

The study’s findings reveal that the lower volatility spillover is evidenced between the green bonds and ESG stocks during tranquil and turbulent periods (e.g. COVID-19 and Russia-Ukraine War). Furthermore, hedging costs are lower both in normal times and during economic slumps. Investing the bulk of the funds in green bonds makes it possible to achieve maximum hedging effectiveness between the S&P green bond (GB) and the S&P 500 ESG.

Practical implications

Both investors and policymakers may use these findings to make wise investment and policy choices to achieve post-COVID environmental sustainability.

Originality/value

Unlike previous research, this is the first to explore the interconnectedness among the major global and country-specific green bonds and ESG assets. The major findings of this study about the lower volatility spillovers and hedging costs between green bonds and ESG assets during the tranquil and turbulent periods may contribute to the post-COVID investment portfolio for environmental sustainability.

Details

Fulbright Review of Economics and Policy, vol. 3 no. 1
Type: Research Article
ISSN: 2635-0173

Keywords

Article
Publication date: 29 August 2023

Zaheer Abbas, Sabeeh Khaliq, Sana Usman and Muhammad Yousuf Rafiq

The coating process is broadly employed in the manufacturing of wallpapers, adhesive tapes, wrapping, protection of fabrics and metals, X-ray and photographic films…

Abstract

Purpose

The coating process is broadly employed in the manufacturing of wallpapers, adhesive tapes, wrapping, protection of fabrics and metals, X-ray and photographic films, beautification, books and magazines, film foils, magnetic records, coated paper, etc.

Design/methodology/approach

In this study, an incompressible flow of non-Newtonian fluid is modeled to inspect the rheological behavior of finite coating thickness in the reverse roll coating process. With the assistance of lubrication approximation theory (LAT), the dimensionless form of governing expressions is simplified. Exact solutions for distributions for velocity, flow rate, temperature and pressure gradient attained utilizing perturbation technique and their variation is presented as well as discussed in graphs. Meanwhile, some important factors from an engineering perspective including coating thickness and transition point were calculated mathematically and are displayed in a tabular manner. Also, streamlines are drawn to observe the flow pattern.

Findings

Prandtl fluid parameters provide a controlling factor to regulate the flow rate, velocity, coating thickness, and pressure gradient leading to an efficient coating process. Moreover, the Brinkman number and Prandtl fluid parameters significantly improve the temperature distribution.

Originality/value

In the literature, this study fills a gap in the theoretical prediction of coating thickness rheologically influenced by Prandtl fluid in reverse roll coating process.

Details

Multidiscipline Modeling in Materials and Structures, vol. 19 no. 6
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 4 August 2023

Argaw Gurmu and Pabasara Wijeratne Mudiyanselage

Most residential building owners often report problems associated with the plumbing systems. If identified at the early stages, plumbing-related defects can be easily repaired…

Abstract

Purpose

Most residential building owners often report problems associated with the plumbing systems. If identified at the early stages, plumbing-related defects can be easily repaired. However, if unnoticed for a long period of time, they could lead to major damages and incur a significant cost to repair. Despite the problems, studies investigating plumbing anomalies and their root causes in residential buildings are limited. This study aims to explore plumbing defects and their potential causes, diagnosis methods and repair techniques in residential buildings.

Design/methodology/approach

This research used data collected through an extensive survey of both academic and grey literature. Through the content analysis, plumbing defects and the associated causes have been identified and presented in tabular format.

Findings

The study investigated the anomalies and causes in the residential plumbing system under five key sub-systems: water supply system; sanitary plumbing system; roof drainage system; heating, ventilation, air conditioning and gas system; and swimming pool. Accordingly, some of the identified plumbing defects include leakages, corrosion, water penetration, slow drainage and cracks. Damaged pipes, faulty equipment and installations are some of the common causes of the anomalies. Visual inspection, hydrostatic pressure test, thermography, high-tech pipe cameras, infrared cameras, leak noise correlators and leak loggers are techniques used for diagnosing anomalies. Reactive, preventive, predictive and reliability-centred maintenance strategies are identified to control or prevent anomalies.

Originality/value

The findings of this research can be used as a useful tool or guideline for contractors, plumbers, facilities managers and building surveyors to identify and rectify plumbing system-related defects in residential buildings.

Details

Facilities , vol. 41 no. 13/14
Type: Research Article
ISSN: 0263-2772

Keywords

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…

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

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